Cacti and Succulents Handbook, Expanded 2nd Edition E-Book

Gideon F Smith

• Herausgeber: CompanionHouse Books
• Kategorie: Lebensstil
• Sprache: Englisch
• Veröffentlichungsjahr: 2022

Seitenzahl: 432

Beschreibung

Learn everything there is to know about cacti and succulent care in this newly updated, easy-to-use volume! Jam-packed with insight on more than 300 types of succulents and cacti, each plant profile contains gorgeous photography, botanical and common names, must-know advice, and more. Also included are simple instructions on choosing the right plants and helping them thrive, plus tips on how to propagate succulents and cacti, repotting, grooming, and pest control. This updated edition features all new photography, updates to scientific names of original plants based on current standards, 70 new cacti species, and 100 new succulent species. Author and award-winning researcher Gideon F. Smith previously served as president for the International Organization of Succulent Plant Study and has published over 500 scientific and popular papers on the taxonomy, biology, and evolution of succulent plants.

Leseprobe

Aloe arborescens ‘Estelle Potgieter’ in full bloom.

A dense stand of a dark-leaved form of Sempervivum tectorum, a species perfectly suited to growing on environmentally friendly green roofs.

Cacti and Succulents Handbook, Expanded 2nd Edition

CompanionHouse Books™ is an imprint of Fox Chapel Publishing.

Project Team

Managing Editor: Gretchen Bacon

Editor: Sherry Vitolo

Design: Wendy Reynolds

Index: Jay Kreider

Proofreader: Nancy Arndt

Copyright © 2018, 2022 by Fox Chapel Publishing Company, Inc.

Cacti and Succulents Handbook, Expanded 2nd Edition (2022) is a revised edition of Cacti and Succulents Handbook (2018), published by Fox Chapel Publishing Company, Inc. Revisions include new cacti and succulent entries and new photographs.

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of Fox Chapel Publishing, except for the inclusion of brief quotations in an acknowledged review.

Print ISBN: 9781620084052eSIBN: 9781637410806

Library of Congress Control Number: 2021953345

This book has been published with the intent to provide accurate and authoritative information in regard to the subject matter within. While every precaution has been taken in the preparation of this book, the author and publisher expressly disclaim any responsibility for any errors, omissions, or adverse effects arising from the use or application of the information contained herein.

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Contents

FOREWORD by Urs Eggli, PhD

PREFACE TO THE NEW EDITION

1. CULTIVATING CACTI AND SUCCULENTS

WHAT ARE CACTI AND SUCCULENTS?

- DIFFERENCES BETWEEN CACTI AND SUCCULENTS

- BOTANICAL IDENTIFICATION FEATURES

- PLANT SHAPES AND FORMS

- NATURAL HABITATS AND DISTRIBUTION

CACTUS AND SUCCULENT DISTRIBUTION

- WORLDWIDE DISTRIBUTION IN THEIR NATURAL HABITAT

CULTIVATING CACTI AND SUCCULENTS

- PROPAGATION THROUGH TAKING CUTTINGS AND SOWING SEEDS

CARING FOR CACTI AND SUCCULENTS

- WATER, LIGHT, AND NUTRIENT REQUIREMENTS

- SEASONAL GARDENING CALENDAR

GARDENING AND LANDSCAPING

- SELECTING THE RIGHT SPECIES FOR THE LOCATION

- URBAN DESIGN TRENDS

- PLANTING FOR COLOR

HOW TO USE THE DIRECTORY

2 COMMON SPECIES OF CACTUS

- 130 CACTUS SPECIES SUITABLE FOR HOME AND GARDEN CULTIVATION

- PHYSICAL DESCRIPTION, IDEAL LOCATION, NATURAL HABITAT, AND GROWING NOTES

3 CACTUS AND SUCCULENT COLLECTIONS

4 COMPANION SUCCULENTS

- DISCUSSION OF 187 EASY-TO-GROW SUCCULENT SPECIES IN 12 FAMILIES

COMMON PESTS AND DISEASES

- SCALE INSECTS, APHIDS, SNOUT WEEVILS, NEMATODES, FUNGAL INFECTIONS

- CACTI AS INVASIVE ALIENS

FURTHER READING

PHOTO CREDITS

ABOUT THE AUTHOR

Foreword

Most books that deal with succulents from a horticultural point of view deliberately focus on plants suitable for indoor collections (from windowsills to greenhouses) in the northern hemisphere—it is a simple fact that the majority of the cactus and succulent plant hobby communities live in those parts of the world. In contrast, the vast majority of succulent plant species hail from essentially frost-free subtropical, tropical, and temperate regions, and growing them in gardens in those areas, or using them for garden and landscape design in suitable climates, should be at least as popular as growing them indoors in adverse climates. While succulents clearly enjoy popularity in public and private collections in milder climates, the literature on how to successfully grow them under garden conditions is surprisingly almost completely nonexistent.

Gideon F. Smith, the author of the present tome, has ventured to fill this gap when he shared his experience and knowledge for an earlier incarnation of this work published back in 2006. His book refreshingly addressed both audiences: those who have to protect their plants from the elements, as well as those who can grow them anywhere out of doors. The need for an updated and expanded edition testifies that the book indeed filled a long-standing void in the literature available in the field. This new and updated edition is thus to be highly welcomed.

But why is it that succulents with their remarkable combination of attractive and simultaneously repulsive characteristics have developed into cherished and sought-after garden plants? Perhaps it is just this enigmatic mixture as shown by fierce spination, or threateningly toothed leaf margins, in combination with colorful and varied inflorescences and flowers that is responsible for their popularity. In addition, succulents are perfect examples of the wonders of plant survival under sometimes extreme and adverse climatic conditions; remarkably, at the same time, they will readily thrive in a garden, regardless of its shape and size. Even a degree of horticultural neglect—a feature certainly welcomed by busy gardeners—will do them no harm.

Crassula ovata “Lady Fingers.”

Gideon, a professional botanist with a long-standing interest in all aspects of succulent plant biology, is to be congratulated for firstly having written this book, and secondly for updating it in the form of this improved new edition. He has successfully amalgamated his botanical knowledge with personal horticultural experience, and presents a prime example of how scientists should not keep exclusively to their laboratories, herbaria, and offices, but should step out and bridge the gap between science on the one hand, and popular horticulture and the hobby community on the other hand.

Johann Wolfgang von Goethe (August 28, 1749–March 22, 1832), the celebrated German author and statesman, was fascinated by a succulent plant, namely what we today know as Kalanchoe pinnata, and its capacity to grow new plants from the leaf margins. While exactly this property makes the plant a problematic invasive weed in many places, it is also a good example of how succulents fascinate people around the world. Gideon has endeavored to enhance this fascination, and I am sure that this revised and updated book will again achieve this goal.

Sukkulenten-Sammlung Zürich

Zürich, Switzerland

June 13, 2017

Urs Eggli, PhD

Crassula ovata “Lady Fingers.”

Preface to the New Edition

The first edition of Cacti and Succulents was published in 2006 by New Holland Publishers Ltd, and in 2018 it was republished by Fox Chapel Publishing, updated and renamed as Cacti and Succulents Handbook. This new second edition of the popular Cacti and Succulents Handbook not only has been updated, but is presented as a considerably expanded book, now with 130 cacti treated—up from the 60 previously included, all of which have been retained in this new edition—as well as an additional more than 100 succulents complementing the 85 included in the previous edition of the book. The number of cacti and succulents included in this edition has more than doubled to over 300. The main purpose of Cacti and Succulents Handbook remains to familiarize readers with a broad selection of cactus and succulent species, as found in the wild and in cultivation.

As before, an important further aim of the book is to present an accessible, user-friendly guide to the identification and cultivation of a selection of cacti and succulents that are common in collections, as well as, tantalizingly, some that are not so common. All the species covered are portrayed with color photographs, and characteristics according to which they can be identified are provided in the accompanying text. One aim of the work therefore remains to offer information that will have wide appeal both among the gardening public and naturalists who want to know more about these fascinating plants.

A further aim is to excite succulent-plant collectors, gardeners, tourists, and natural historians in general about the magnificent global succulent flora—including both cacti and succulents. In this regard, a selection of easy-to-grow and other succulent species, spread across 12 families, is discussed, with, additionally, a large number of cacti, all of which are included in the family Cactaceae, being treated.

To keep the book accessible to beginners, non-technical language is used as far as possible. Given the popularity of the earlier versions of the book, this approach clearly appeals to amateur collectors and professional botanists alike.

Succulence is found in the leaves, stems, and roots—or a combination of these organs—of about 10,000 plant species globally. These species that often, but not always, occur in regions where rainfall is low or erratic are spread across about 80 flowering plant families. Even in high-rainfall regions, locally dry sites, such as sheer cliff faces or the well-drained forks of tree branches, abound; in these positions, succulents often also grow in large numbers. Succulents occur in most arid, subtropical, Mediterranean, and tropical regions of the world, but perhaps the best known of these are southern Africa, which is host to well over 4,700 such species, and Mexico and the southern United States.

Since many readers have become familiar with recent developments in the circumscription of families and genera that include the succulents treated here, family concepts presented are as far as possible retained from the previous edition. Therefore, in this new edition of Cacti and Succulents Handbook the cacti and succulents are again discussed under the families in which they are included. Family concepts are increasingly well-known, and it will be easy to locate plants with similar characteristics. As before, introductory pages are provided to each of the families dealt with. These introductory texts give some basic and interesting background information about the families and illustrate typical representatives as well as some of their characteristic features. The family introductions are followed by the species treatments.

A multicolored selection of Aloe cultivars.

Over the past few years there have been a number of developments regarding small- and large-scale domestic and corporate gardening:

•Planting indigenous no longer means planting material from your country. The scope has been narrowed: select plants from your immediate region. This makes sense as material from the winter rainfall region of a country planted in the summer rainfall region of that country means an investment in environmentally expensive irrigation at a time of year when plants should typically be in a resting phase.

•Water-wise gardening, too, has been tightened, and many people are now developing no-irrigation gardens that rely exclusively on rainfall.

•The negative impact that humans can have on the health of our planet is not only appreciated—environmental health has become a way of life.

With these developments no longer negotiable, cacti and succulents have taken their rightful place as popular gardening subjects. They furthermore come in a large variety of shapes and sizes, with some being low-growing miniature soil huggers that look like the rocks and pebbles among which they grow while others are trees of over 65 ft. (20 m) tall. Regardless of where you garden, there will be succulents to suit your taste and style, and the space you have available.

A further recent development has contributed to the popularity of succulents and the smaller-growing cactus species:

•Over the past 10 years these plants have become very popular in the sustainable succulent arts and crafts trade.

Small plants—especially those with their leaves variously arranged in a rosette—are being used in creating a wide range of foliage and floral assemblages that can be put to a wide range of uses as truly living decorations for indoor and outdoor domestic spaces, in the office, at private and corporate events, as personal adornments, and much more.

Given the popularity that succulents have attained in specialist collections and horticulture in general, this book is intended to further inspire gardeners who prefer low-maintenance and water-wise plants for cultivation. Fortunately, the variety of succulents available in nursery and plant centers today range from mature specimen trees suitable for estate and ranch gardens, to tiny ones that will thrive in windowsill pots or in hanging baskets.

I hope you will derive much pleasure from this expanded and updated book.

August 2021

Gideon F. Smith

Kalanchoe luciae in full bloom.

CULTIVATING CACTI AND SUCCULENTS

Cacti and succulents invoke a response in anyone who lays eyes on them. They are simply too dramatic and diverse for them not to be noticed. They might be stared at in bewilderment, or dismissed as bizarre, but they can never be ignored, for they are fascinating and, to many plant collectors, highly attractive and desirable.

Their magnificent architectural and sculptural shapes will enhance most garden settings. Columnar and treelike types look like sentries standing silent guard outside a house or beside a swimming pool.

Cacti and succulent flowers are exceptionally decorative, even though some tend to be short-lived. Flowering is not just another routine of nature; it is a real event.

Yucca brevifolia, the Joshua Tree, (center) in the Mojave Desert, Nevada.

Agave utahensis var. eborispina.

What are Cacti and Succulents?

In cultivation, cacti and succulents generally have globular, columnar, leaflike, or wiry, rosulate, or treelike bodies that are fat and swollen. They are variously adorned with spots, fissures, and ridges and, of course, often rather rapier-like teeth and spines.

In their natural habitats, numerous species alter their appearance with the seasons: from seemingly lifeless at the height of the arid season to exploding with vigorous growth when the rains finally arrive, after which they usually flower, sending forth spectacular large-scale, almost overgrown, clustered or single blooms.

Even when very young, as developing buds, cactus and succulent flowers hold the promise of striking beauty. They take their time to reach maturity then, all of a sudden, they burst into vivid color, often fading within a few days. This is, of course, part of their charisma and contributes to turning each flowering into a real happening.

During the rainy season, cacti and succulents absorb moisture that must last them until the next, often unpredictable, showers arrive. The ridges and grooves of their fluted stems and leaves expand as they absorb life-giving water.

This precious cargo is then slowly and carefully used to sustain the plants through the next dry season (sometimes through multiple dry seasons), until they can once again replenish their water-storage organs.

Thus the cycle continues and the plants keep on surviving in an endlessly arid environment.

Cactus and succulent species differ vastly in shape and size. Some, such as the well-known saguaro or “cowboy cactus” (Carnegiea gigantea), or the giant yuccas (Yucca filifera and Yucca aloifolia) and tree aloes (Aloidendron barberae and Aloidendron dichotomum), can reach a height of over 65 ft. (20 m), while others are no taller than a few stacked coins.

Some cacti and succulent plant bodies remain underground, exposing only their flowers to pollinators; others take the form of bougainvillea-like scramblers, shrubby trees, climbers with angled stems, spiny, rounded barrels, or are spindly and thin-stemmed with massive, tuber-like underground storage organs—the list is almost endless and offers an embarrassingly rich variety from which to choose plants to cultivate.

This diversity is echoed in the habitats that they occupy. These range from high-rainfall tropical rainforests, to some of the hottest and most arid deserts on earth, and from sea level, where they are exposed to desiccating salt spray, to high mountains where they may be seasonally covered by snow.

As horticultural objects to admire, collect, and grow, cacti and succulents find favor among modern city dwellers, regardless of whether they have large, sprawling, landscaped gardens or postage stamp–sized balconies or rooftop gardens with space for a few choice plants only. This popularity can be attributed to a number of factors:

• Most cacti and succulent species tolerate extreme horticultural abuse. Indeed, most species are not precious, princess-like plants requiring undue pampering. Plants will easily stay firm and green, even if somewhat deprived of water and nutrients. Container-grown plants do not require regular repotting, and grow quite happily, even when their roots are pot-bound.

• Most species are not fussy about climate and growing conditions and, with some attention to a few basic rules, will survive as easily indoors as outside. There will always be a selection of species that will thrive in your local conditions, so you don’t need to manipulate the micro-climate to have a group of plants to boast about. They require little attention to look their best, which is handy if you don’t have much time available for gardening.

• Furthermore, although most species are fairly slow-growing, they will give years of pleasure. This contrasts sharply with garden annuals that often require labor-intensive horticultural care.

• The juice-filled bodies of most cacti and succulents are exceedingly resistant to attacks by pests. If they are subject to insect infestations, these can generally be treated with great ease.

BOTANICAL CLASSIFICATION

Botanical, indeed biological, classification is most commonly done according to a so-called hierarchical system. This means that each higher rank (such as an order or a family) includes a number of subordinate groups that share certain characteristics. A family, for example, consists of one or more genera, each of which has more in common with one another than with genera of other families. With genera it’s the same, but they comprise one or more related species, of course.

For collectors of succulent plants, the genus and species ranks tend to be the most important categories, as collectors often become interested in species with a similar appearance and then, once the collecting bug has bitten, expand their collections with similar-looking entities. And, of course, species included in a single genus often exhibit numerous essentially similar characteristics. However, there should be discontinuities among the characteristics of species as, without them, classification would be impossible. In addition, a reproductive barrier is sometimes encountered between different species. In the plant kingdom, however, this reproductive barrier is usually absent as hybrids between even distantly related species can sometimes be fully fertile. In contrast, interspecific hybrids in the animal kingdom are usually completely infertile.

See How to Use The Directory on page 36 for more explanation of how scientific names are used and displayed in the directory.

SCIENTIFIC VERSUS COMMON NAMES

Strictly speaking, all plants have a single, unique Latin or Latinized scientific name. This is the ideal situation, but it does not always apply, as some plants are known by different names, often depending on which authority is asked to supply a name for a plant.

At the species rank, a scientific name consists of a combination of a genus name and a specific epithet, which together constitute the species name (e.g., Yucca filifera).

Not all species have common names. Although these are often very interesting and descriptive, they tend to be poorly known and are not that widely used. Furthermore, a single species can have many common names, which can create confusion, especially if the names are only of limited regional use.

DEFINING CACTI

The broadly defined group of about 10,000 water-storing species that is distributed worldwide and is generally referred to as “succulents” belongs to as many as 80 different, often unrelated, plant families. Of these, about 1,800 are species of cactus but, in vivid contrast to the rest of the succulents, all cacti belong to only a single family of flowering plants, the Cactaceae. All cacti are therefore succulent in that they store water in at least one of their organs—the stems, leaves, or roots. Even the leaves of the bougainvillea-like Pereskia species, which are large, flat, and persistent, are somewhat fleshy.

Fortunately, it is quite easy to distinguish cacti from succulent plants because they have certain characteristics that set them apart from all other plants, including the non-cactoid succulents, some of which, such as the euphorbias, closely resemble cacti, especially from a distance. Although flower characteristics are the most useful indicator when plants are identified, it is not necessary to have flowers available when trying to decide whether one is dealing with a species of cactus.

The following, easy-to-observe characteristics make it simple to recognize a cactus, even when it is not in flower.

1. Without exception, cacti are characterized by the presence of small, cushion-like structures on the plant bodies called areoles (seen here as white, furry “spots” on Parodia horstii). These are specialized structures from which all cactus growth occurs and include new stem segments (also called pads), flowers, and spines. The spines of species of the milkweed family, the Euphorbiaceae, do not arise from areoles; a clear indication that the cactus-lookalike euphorbias are not cacti at all.

2. Representatives of the cactus family, such as this columnar Pachycereus marginatus, are mostly, but not exclusively, stem succulents; that is, the inner tissues of their stems serve as storage organs. This indicates clearly that many species are naturally distributed in areas of low rainfall. Cacti that occur in high-rainfall tropical areas are restricted to locally dry sites, such as the well-drained humus pockets accumulating in forked branches of trees or small pockets of soil against cliff faces.

3. The plant bodies of many cactus species, such as the opuntias or prickly pears, consist of leafless flattened stem segments (also referred to as pads, paddles, or joints), depicted here for Opuntia phaeacantha, commonly known as the tulip prickly pear. These segments can also be angled, cylindrical, or leaflike. The pads are various shades of green and have taken over photosynthetic (food-producing) activities performed by the leaves of conventional plants.

4. Most, but not all, cactus species are armed with spines, as here on the ribs of Pachycereus pringlei, the Elephant cactus or Mexican giant cardon. These vary tremendously in terms of shape, size, and rigidity, and clear distinctions can be made between the different types of spines carried on the areoles of cacti, that is, whether they are positioned centrally or radially. The spines always serve one or more functions, such as protecting plants from grazing animals, or against excessive solar radiation, or assisting some species with the dispersal of stem segments when they get hooked onto the coats of roving animals.

For the purpose of simplification, no distinction is made in this book between the different types of central or radial spines of cacti.

5. The areoles of some species, such as this Opuntia microdasys, are adorned with tufts of small, bristly hairs called glochids. To the layperson these miniature structures are only a variation on the theme of “spines” as they can cause immense irritation to exposed skin. The glochids of most species are barbed, like fish hooks or harpoons, and difficult to dislodge once they have become established in one’s flesh.

6. In many species of cactus, the flowers are produced from a so-called cephalium. This refers to a densely woolly or bristly “head,” which may occur at the apex of a globular cactus or on one side of a columnar cactus. In the latter case, they are usually referred to as lateral or pseudo-cephalia, as seen here on Cephalocereus columna-trajani.

7. The bodies and flowers of cacti come in a bewildering diversity of shape, size, and color. However, cactus flowers are generally fairly large and brightly colored, like this Echinopsis vatteri, unless the species is night-flowering, in which case its flowers are usually a muted white or creamish color. This, along with the marvelously variable shapes and sizes of their stems contributes significantly to their allure for the collector. The flowers can be broadly regarded as funnel-shaped, starting out thin at their points of attachment to the areoles on the stems, then broadening considerably toward their tips, exposing the reproductive organs (pollen-bearing stamens and receptive stigmas) to animal and insect visitors that effect pollination.

8. Plant shape is a very constant character within a particular species of cactus. However, it is not uncommon to find vastly divergent body shapes in a particular genus. The architecture of cactus plant bodies, which results in their definitive shapes, can be divided into a number of very distinct types that facilitate plant identification.

IDENTIFYING CACTUS PLANT SHAPES

Mammillaria muehlenpfordtii

Globular or spherical cacti with small to medium-sized, globular to spherically rounded plant bodies are the most popular among collectors, especially those with only limited space for a few pots. Many species with this growth-form remain solitary, while others tend to sprout offshoots from the base, resulting in anything from small to large clumps of very attractive cushion-shaped plants.

Harrisia martinii

Climbing cacti. Species of cactus belonging to this group have comparatively weak, ropelike stems that will rapidly climb onto any nearby supporting structure.

Stenocereus thurberi

Columnar. These species tend to be large-growing, with their stems often reaching a height of several meters. Some species produce single stems or “columns,” while others branch from the base, or higher up the stem, to produce sparse to dense candelabra-like clumps, with a rather bushy collection of cactus stems.

Schlumbergera truncata

Hanging cacti. Hanging cacti have either thin, pencil-, or ropelike stems, or fairly broad leaflike, sometimes flattened stems, which invariably dangle downward as they cannot support themselves. They generally make perfect subjects for cultivation in hanging baskets.

DEFINING SUCCULENTS

To even attempt to provide a list of defining characteristics for succulents would be futile, short of stating that they do not have areoles, as cacti do. Succulents are simply too diverse and distributed among too many families to define them in a few paragraphs. The approach followed here is to briefly mention a selection of some of the more easily recognizable characteristics of the families that include succulents where their representatives are discussed in the book.

Lengthwise, along the margins, the leaves of Echeveria runyonii ‘Topsy Turvy’ curve down to give the rosettes an upside-down appearance. Inset photo. The bright orange flowers are very large and carried in fiddlehead-like coiled inflorescences.

Succulents in the snow. The thick-leaved Claytonia megarhiza, the alpine springbeauty, on the Rocky Mountains near Denver, Colorado.

Cactus and Succulent Distribution

Cacti and succulents are well-adapted to an arid life, having developed a host of water-saving mechanisms in order to survive. However, “arid areas” should not only be equated to deserts. Contrary to popular belief, extreme desert areas are not rich in cactus species. By far the largest number of cacti occur in dry, savanna-like areas where they evade the scorching sun by seeking out the protection provided by associated shrubs or grasses.

WHERE ARE CACTI FOUND?

In their geographical distribution, cacti are more or less restricted to the Americas. Only a single subspecies, mauritiana, of a variable species of hanging forest cactus, Rhipsalis baccifera, occurs widely in Africa, with this and other subspecies of the same species inhabiting the islands of Madagascar and Sri Lanka in the Indian Ocean.

The largest diversity of cacti occurs in Mexico and the southern USA, but significant numbers come from northern Argentina, southern Bolivia, Peru, Brazil, and Paraguay. In these countries, cacti are not restricted to arid desert-like parts only. They also occur in extremely cold climates, with some even tolerating the low winter temperatures of the East Coast of the USA. Still other species grow on some of the highest mountain ranges of South America.

Surprisingly, a significant number of cacti species are native to humid tropical rainforests, while other species are found along the Pacific coastlines of Mexico and California, where they are subjected to salt spray and fog drifting in from the ocean.

Given these widely divergent natural habitats of cacti, plus the phenomenal resilience of most species from a horticultural point of view, there are species suitable for cultivation in almost any environment and location, from a small windowsill collection to a large, natural outdoor xerophytic (cactus-strewn) landscape.

WHERE ARE SUCCULENTS FOUND?

Succulents occur on all the continents, with the exception of the poles. They have a vast distribution range and inhabit both hemispheres, from northern continental Europe southward to Australia, and even to some of New Zealand’s islands.

Admittedly, at their northern and southern extremes, succulent diversity is low, with the majority of species concentrated much closer to the equator.

The highest natural concentration of succulents is in southern Africa, where an astonishing 47 percent-plus of all the world’s succulents occur in an area that amounts to less than 10 percent of the global land surface.

Mexico and the southern United States are also home to large numbers of succulents.

HOW DO CACTUS PLANTS SURVIVE?

By reducing, virtually to zero, the amount of leaf surface exposed to an arid, desiccating atmosphere, cacti avoid losing moisture via their leaf stomata (microscopic “breathing” apertures on the leaves of most plants that allow them to partially regulate their temperatures through evaporative cooling).

Unlike cacti, many species of succulent plants do have leaves. In certain cases, such as the aloes and agaves, the leaves are thick and fleshy, and accumulate large quantities of water when it rains. The leaves then remain fat and turgid for long periods, as the moisture is slowly released to maintain essential physiological processes in the plant’s body—until the next downpour starts the process all over again.

Two succulent species, Euphorbia ledienii var. ledienii (foreground) and Aloe ferox (background), growing together in the Eastern Cape, South Africa.

The broad natural geographical dispersion of cactus and succulent species is depicted on the map, although some species may occur outside these areas. Cultivated plants can be found throughout the world, provided the growing conditions are suitable.

Six-month-old seedlings of Kalanchoe nyikae.

Cultivating Cacti and Succulents

Cactus plants are some of the most desirable species to cultivate as they are so tolerant of a variety of different growing conditions. Most species, regardless of their climatic preferences, thrive both indoors and outdoors, and most flower annually.

Many cactus species can be grown from cuttings that root easily, making it possible to quickly obtain large plants that will proliferate and flower. Apart from being grown in open garden beds, a wide selection of species is also suitable for long-term container gardening, requiring comparatively little aftercare once they become established in pots.

There are almost as many opinions about the successful cultivation of cacti as there are collectors of these plants. Some species are more difficult to grow than others, but the following guidelines should work for most species.

SELECTING THE RIGHT PLANT

Although young cacti are available from nurseries and specialist growers, part of the challenge is to grow your own from scratch. Cultivating plants is not for everyone, as it takes time and dedication but, for an avid gardener, it offers many rewards. The first step is to select the “parents” of your future cacti.

TAKING CUTTINGS

A cutting is essentially a section of a larger plant that is identical in genetic composition to the plant from which it has been removed. Cuttings range in size and length from a little globule only a few millimeters long to ones that can be quite large and several centimeters in length. “Cuttings” longer than 3 ft. (1 m) are sometimes called truncheons.

The cacti and succulent species that are best suited to propagation from cuttings are typically those that grow as branched shrubs or produce basal sprouts. Conversely, if the species you want to propagate remain as single-bodied, unbranched specimens for the duration of their life cycles, you may not have any other option but to raise the next generation from seed.

Cuttings should, ideally, be taken from healthy, strongly growing plants. As a rule of thumb, propagation is best at the onset of the growing season, that is, in spring for summer growers and in autumn for winter growers. However, many experienced growers claim that, short of a few hard-to-grow species, propagation of most cacti and succulents can be attempted throughout the year, especially in mild climates.

However, if you are in doubt about the possible success of your propagation efforts, or fear that you may end up with a badly mutilated, highly prized specimen and no rooted cuttings to show for it, then wait for the onset of the next growing season. Otherwise, if availability of material is not a problem, give it a try at any time of the year.

Generally speaking, it is safest to attempt propagation from pieces of a parent plant that have attained a reasonable degree of maturity. It is much easier to lose material if it is of insufficient girth and/or length. Remember, the cutting has to sustain itself for a few days, weeks, or even months on accumulated water and nutrition reserves, before it produces its own roots.

Although many species are not too fussy when it comes to the medium used for rooting cuttings, a mixture consisting of equal parts of gritty sand and sifted potting mix generally works well for many cacti and succulents.

Freshly planted cuttings should be given some protection against severe sunlight, at least until the cutting has rooted. The soil mixture should be kept moist, not wet throughout. However, cuttings generally do not need to be fed. At this early stage in the life of a new, rooted plant, emphasis is on its survival (that is, striking root), rather than on producing fat, new growth.

The newly rooted material can be kept in the rooting mixture for a long time, provided the size of the container used conforms to that of the cutting.

However, if you deliberately used a very small saucer or seedling tray in which to root cuttings, the plant material can be transplanted as soon as it shows signs of active growth.

The cuttings will usually show new growth within a matter of weeks (even days, in the case of some species).

HOW TO TAKE A CUTTING

Use a sharp knife or pair of pruners (secateurs) to remove a section of the cactus plant body, preferably at the point where the stem segments (pads) join together.

This is usually the thinnest part of the cactus stem and, in most species, it is quite easy to cut through the joints. In the case of suckering species, or globular ones that proliferate through forming small plantlets, the suckers or miniature plants should be removed carefully with a sharp knife, as close to the main stem as possible.

Leave the removed parts in a shady position for a few days, to allow them to dry before they are planted.

To root these cuttings, dip them into commercially available rooting hormone powder and insert them into a friable, well-drained soil mixture containing coarse (sharp) sand or gravel (grit).

The length to which a cutting should be inserted into the soil depends on the size and length of the cutting. Generally, a good insertion length for a small to medium-size cutting is one that will allow the rootless plant material to remain erect in the soil mixture. Large cuttings should be staked to provide support and prevent them from toppling over.

To take a cutting, use pruners (secateurs) or a sharp knife to remove a section of the cactus plant.

To root cuttings, dip them into rooting hormone powder.

Insert the cutting into the soil at sufficient depth to allow it to take.

SOWING SEEDS

Cacti seeds are generally borne in the juice-laden, fleshy fruit. The best germination results are usually obtained from seeds that are freshly collected as soon as the fruits are ripe and burst open.

To prepare the seeds for sowing, the sugary pulp in which they are embedded should be removed. Seeds can be manually picked out of the sugary pulp, or the pulp can be washed off with water, and the seeds left to dry. Once they are dry, wash the seeds with a weak solution of household bleach, and leave them to dry again, before sowing.

Sow the seeds sparingly in large, flat seed trays that have been filled with a soil mixture consisting of one-third coarse (sharp) river sand (ideally not quarried sand, which is too fine), one-third well-rotted and sieved compost, and one-third garden soil.

To promote germination, seedling trays should be provided with adequate air circulation, reasonable warmth, and high humidity.

Ventilation is particularly important once the first seedlings appear, as it promotes the cyclic drying out of the soil, but take care that the soil never becomes bone-dry, as this could kill the seedlings. To keep the soil in a seedling tray moist, but not wet, stand the tray in a larger container of water and remove it as soon as water appears on the soil surface. Seedlings have very weak root systems, and watering them from below also prevents the seedlings from being washed out of the soil by a careless jet of water. Young seedlings generally don’t need additional feeding, as the sifted compost mixture contains all the required nutrients.

High humidity can be created by inserting a seed tray into a transparent plastic bag and closing it with a piece of thin wire. To prevent fungal spores from ruining newly germinated seedlings, add a commercially available fungicide to the first watering of the tray, before placing it in the bag.

Once the seedlings are about the size of an adult person’s pinky fingernail, they can be removed from the seedling tray and potted into small, individual pots. Although they can be potted out when smaller, the risk of losing them is much greater, as their root systems are very small and fragile at this early stage of their development.

GERMINATING TEMPERATURES

A temperature of between 59°F and 77°F (15°C and 25°C) is ideal for germinating cactus seeds. Temperatures that drop below or rise above these levels can delay germination or halt it altogether.

Plants of Echinocactus grusonii (yellow, ball-shaped plants in the foreground) and Pachycereus pringlei (green, columnar plants in the middle ground) have been planted out into raised beds.

OTHER METHODS OF CULTIVATION

When the pads of some species, especially opuntias, are simply severed and left on the ground, they will spontaneously root and form small plants at some of the areoles.

Other species, especially tree-dwelling epiphytic cacti, such as species of Schlumbergera, will form aerial roots that facilitate the formation of a healthy rootstock once they have been removed from the mother plant and planted in the desired spot or container.

Advanced growers may attempt to graft the more difficult-to-grow species onto rootstock plants that grow easily. The challenge is to ensure that the vascular (transport) tissue of the material is aligned and that the two plants are securely attached to one another. This takes some practice and beginners should not be discouraged if their early grafting efforts fail.

COMMERCIALLY AVAILABLE SEED

Packets of seed for cacti and succulents can occasionally be found at nurseries and garden centers. These seeds have usually been washed and dried and can be sown directly into seedling trays.

Specialist nurseries or horticultural societies sometimes offer seed that can be ordered from their annually distributed seed catalogs. These can be sown upon receipt.

DEADHEADING

This is the process through which the fading flowers of a perennial shrub or annual herb are removed to prevent the formation of fruit and seed. Seed production is a high-energy process, so plants in this stage of their life cycle are unlikely to produce more flowers. However, if the spent flowers are pinched out (deadheaded), many plants will be stimulated to produce a second crop of flowers.

Not many cacti or succulent species require deadheading, but some companion plants, such as the profusely flowering daisy shrubs (including the white-purple flowered Dimorphotheca fruticosa of which the first crop of flowers are fading), may be enticed into another burst of color if they are given this treatment in midsummer.

HANDLING CACTI

Handling ferociously spined cactus plants, especially medium- to large-sized ones, can be tricky.

When planting or transplanting, an easy method is to wrap thick layers of newspaper around the plants before moving them. Another option is to wear heavy protective gloves that will not be readily pierced by the spines.

Spring-loaded wooden tongs (of the type used for turning barbecued meat) can be useful when handling smaller cactus specimens.

The easiest way of propagating Echinopsis huascha is by taking stem cuttings that will root very rapidly and soon give rise to identical plants. The reddish orange flowering form is depicted here.

It will take a bit of experimentation to find the right combination of light, water, and nutrients to have healthy plants, but the wait is always worthwhile. For this specimen of Ferocactus wislizeni subsp. herrerae, the perfect balance has been found.

Caring for Cacti and Succulents

All plants, including cacti and succulents, have three basic requirements to ensure healthy growth: water, light, and nutrients. Successful cultivation of these fat-bodied plants depends on knowing how these three requirements should be regulated.

Healthy, well-cared-for cacti provide the grower with years of pleasure, but at least as many plants die from under-watering and inadequate nourishment as from overwatering and excessive feeding. Cacti are truly tough plants, although they do require attention if you want to keep and develop a desirable and flourishing collection.

When it comes to gardening, cacti and succulents cater to individuals with a wide range of needs and skills, from those with not-so-green thumbs to gardeners and horticulturists who thrive on the challenge of bringing hard-to-grow species to flowering maturity.

To achieve success with growing cacti, remember the following:

Give plants too little water rather than too much.

Bright light rather than deep shade is best.

Give sufficient fertilizer, especially when the plants are in flower.

WATER

Although it is not difficult to master the art of watering cacti, it requires some experimentation and careful observation. The golden rule should be “less is more”; that is, err on the low side until you are accustomed to your plants’ needs. They may suffer from water stress at first, but you are less likely to lose them.

WATERING OUTDOOR PLANTS

While most cacti and succulents can survive on comparatively little water, if you want them to flourish, they should receive adequate water. This is especially true if you want healthy plants, even in times of drought.

Water should not be withheld during the growing and flowering seasons, when plants actively recycle organic carboniferous material and inorganic nutrients as part of the process of increasing their body mass, and accumulate resources to eventually produce their magnificent blooms.

However, once a plant begins to enter its resting phase, which could be in winter or summer, depending on the species, it is usually advisable to limit watering to the occasional spraying.

Plants grown in open beds obtain their water mainly from rainfall. If this is insufficient, then additional irrigation should be provided from time to time to enable them to absorb a sufficient amount of water.

Fortunately, many cactus and succulent species have a means of demonstrating when they need water: their ribbed stems contract like the fins of a concertina, or their leaves become flat. When these plant organs contract, it is a sure sign that the plant is in dire need of water. But do not wait for the first signs of stress before you give water.

Plants that always suffer from water stress (cacti with ribs closely packed rather than expanded), are more prone to succumb to attacks from a variety of pests. To keep your plants healthy, do not allow them to go without water.

Cacti and succulents do not like “cold, wet feet,” meaning they prefer not to spend long periods in cold, water-logged soil. This is less of a concern if the plants are grown in open beds or unsheltered spots where water rapidly drains away or the sun naturally dries out the soil. Plants grown in such positions are less prone to rotting, even if at times they receive too much rain from unseasonably high downpours.

WATERING INDOOR PLANTS

Container plants kept indoors or away from the direct effects of the elements depend on the gardener to regulate their watering regimes wisely. One way of doing this is to grow your plants in soil mixtures that retain moisture to varying degrees. For example, if you have a heavy hand with the watering can or hose, make sure that the soil mixture is friable and open, making for good drainage.

Another way to regulate soil moisture in containers is to grow cacti in different types of pots. Plastic pots are popular and affordable but they tend not to breathe, and therefore retain water. On the other hand, clay and ceramic pots lose water through evaporation, so plants grown in them should be watered more frequently than those in plastic containers.

Ideally, potted plants should be watered in the morning, to allow the foliage to dry off before nightfall (this is particularly relevant when nighttime temperatures are low).

In a cold climate, it can be detrimental to give container plants, regardless of whether they are kept indoors or in a greenhouse, tap water that is only a few degrees above zero, as the plants may go into shock.

Before watering, make a point of allowing the water to reach room temperature (± 60°F/15°C). This can be done by filling a few buckets or watering cans and leaving them to stand indoors for a few hours before watering the plants.

Although succulents are not overly susceptible to cold-water stress, they will benefit from an application of water that has reached room temperature.

Plants that are kept outdoors are generally more likely to become progressively acclimatized to the cold weather, and therefore also the lower temperatures of the tap water.

With suitable protection against the elements, particularly very low temperatures and excessive rainfall, some cacti, such as Opuntia humifusa can be grown outdoors. This specimen is cultivated in climatically severe Zürich, Switzerland, in an open bed.

SUMMER AND WINTER WATERING

There is no simple recipe for advising on the right amount, or frequency, of watering, as there are so many environmental and other factors that determine a plant’s needs. This includes the climate, type of soil, ambient air temperature, and local wind conditions.

However, bear in mind that, regardless of any other preference of the species for summer or winter rainfall, neither cacti nor succulents appreciate standing in wet ground, where soil moisture does not drain away.

Crassula capitellasubsp.capitella‘Campfire Plant’ has bright red leaves and narrow, erect, white-flowered inflorescences.

LIGHT

If it is difficult to advise on the exact watering needs of your plants then, by comparison, the question of exact light conditions is much easier to answer. If cacti and succulents receive too little light, they will etiolate (become thin and whitened) unnaturally. If they receive too much light, they will become sunburnt. This usually manifests as unsightly spots on the surface, where the tissue was damaged.

Plants that prefer full sun but have been kept in the shade for a while should be acclimatized slowly, otherwise there is a good chance that they will be badly scorched, or even die, as a result. Remember that even though some cacti and succulents grow in desert conditions, they often survive in the shade of nurse plants where they are protected from the damaging rays of the harsh desert sun.

Although it is difficult to be absolute, cacti species with prominent spines generally need high levels of sunlight to retain their shapes and sizes. Species with flattened, leaflike stems require good, but filtered, light. This can be done very easily at home by growing these plants in dappled shade or on a patio in full shade.

NUTRIENTS

Most plants obtain the life-giving inorganic nutrients necessary to sustain growth and development from the medium in which they grow.

This also applies to cacti, even those that grow in very small rock crevices or as epiphytes in the forks of trees. In both cases, nutrients are obtained from the small amount of windblown soil or organic leaf-litter that accumulates over the years in these microhabitats.

In open garden beds, plants benefit from a regular inflow of nutrients as part of the normal cycle of life. But, even so, it is occasionally necessary to dig decaying organic matter (compost) into the ground to replenish depleted nutrient sources. Plants that are regularly fed in this way stay healthy and are far less prone to fall victim to insect infestations and other detrimental pests and diseases.

Although special feeds are sometimes offered for cacti and succulents, most species tend to respond well to commercially available plant feeds. Liquid and foliar feeds are easy to apply and work very well.

Feeding is usually done at the onset of a species’ growing season, and regularly (monthly) thereafter, up to the end of the growing season for that species.

SEASONAL GARDENING CALENDAR

Once established, most cacti and succulents require very little aftercare and maintenance, other than the normal tasks required by horticulturally tolerant plants. Some seasonal gardening hints and suggestions are given below, but the priority tasks will naturally differ according to where you live and what sort of plants you have, and whether they are grown outdoors all year round, or spend all or part of the year indoors, either in a hothouse or in some other form of shelter.

The division of the gardening year into seasons depends on the climate in your area. If you are a new gardener, a good tip is to use a notebook to record what you do, from planting, to pruning, weeding, feeding, and how often you water. By including day-to-day details, such as the rainfall or whether it was sunny or overcast, you will soon build up an invaluable “personal almanac” to refer to year after year.

FIRST MONTH OF HIGH SUMMER

High summer does not mean the planting season is over. If planted now, most cacti and succulent species will still root quickly enough to ensure they can withstand the cold winter months.

• Cut back Pelargonium species (for example, Pelargonium peltatum), that have completed their first flowering of the season. This does not apply to the usually leafless, succulent-stemmed Pelargonium tetragonum, for which pruning should hardly be required.

• Plant out Portulaca seedlings now, but be sure to provide them with initial protection against the midday sun, and water them regularly. This species does well if you require small plants to grow in the crevices between paving bricks.

• Frangipani trees are now in flower.

• For patient gardeners who planted Agave wercklei about eight years ago, the long wait is finally over. In midsummer, this magnificent species produces a towering inflorescence at least 13 ft. (4 m) tall. The upper parts of the flowering pole, or stalk, of this non-suckering species are covered in large clusters of bright yellow flowers.

SECOND MONTH OF HIGH SUMMER

The weather is still very warm and most plants will benefit from an occasional, thorough drenching, ideally with collected rainwater. If you live in a summer rainfall region, make sure the soil is well mulched, especially around shrubs and trees, to promote the absorption and retention of moisture.

•Portulaca cultivars perform well and will provide some color, regardless of whether your garden combines various plants with succulents, or is a near-exclusive succulent one.

• The very drought-tolerant, bottle-trunked Australian flame tree, Brachychiton acerifolius, now produces spectacular masses of crimson red flowers.

A plant container densely planted with a selection of succulents, including a purple-flowered mesemb, an aloe, and ×Graptoveria‘Fantome’ (the gray rosettes in the center).

FIRST MONTH OF LATE SUMMER

The late summer days are often still exceptionally warm; in some areas, the temperatures are only peaking, and winter rainfall areas are now usually quite dry. Slowly but surely, it is time to say goodbye to summer, at least in terms of planning for the year ahead, and start preparing your garden for autumn and winter, even for spring.

• Do not feed established, summer-growing succulents and non-succulents if your area experiences very cold winters. Feeding will stimulate new growth, which will be destroyed by the first frosts. It is too early to awaken winter-growing succulents from their required and essential summer slumber.

• If the summer rains were good, then thin out and prune climbers, such as the cactus Quiabentia verticillata, that have become overgrown. Stake, trim, or tie down creepers (such as the succulent-leaved canary creeper Senecio tamoides) that have grown too vigorously during the high summer.

• Plants looking very good at this time of year include frangipani (Plumeria species and cultivars) and portulaca (Portulaca grandiflora cultivars).

SECOND MONTH OF LATE SUMMER

• Remove the spent inflorescences of summer-flowering succulents, unless you want to collect the seed.

•Pests: Be on the lookout for red spider-mite infestations, especially on species of aloe. This pest comes out in force in warm and dry conditions and, in summer rainfall areas, plants produce softer growth, making them highly susceptible to attack. Spray infested plants with a commercially available miticide.

FIRST MONTH OF AUTUMN

As days get shorter and temperatures begin to drop, plant growth is noticeably slowing down. Now is the time for a garden cleanup as leaves begin to change color and are shed.

• Stop feeding container plants and give them less water.

• Cut back the succulent-leaved Plectranthus neochilus (poor man’s lavender), if flowering is finished, but flowers need not be removed. It will resprout quickly.

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