GROWING CACTI AND SUCCULENTS

Succulents have many virtues. They are able to withstand a dry atmosphere, do not demand constant attention, and can certainly be left on their own for a week or two. But best of all they are delightfully attractive. Their beauty does not depend solely on their flowers – albeit often short-lived – but also on their attractive shapes and spines. Cacti belong to the Cactaceae family, which is only one of several groups of succulents, and are succulents as much as any of the others. But many enthusiasts tend to give the cacti special rank and talk of cacti ‘and other succulents’.

Succulent plants can be considered to be the camels of the plant world – for they are able to store water to help survive periods of droughts. The water is stored in large cells in the stems and leaves. Having stored the water it is important not to lose it by excessive transpiration.

and therefore many succulents are leafless. The thickened stems are often able to photosynthesize and produce plant-building materials: and the plant exposes the minimum surface to the drying effects of wind and sun. Some succulent plants have leaves which are relatively small and very thick; those with more delicate leaves shed them in the dry season. The stems and leaves of succulents often have a waterproof, waxy coating to reduce water loss. It is not necessary to travel to foreign places to find succulents. Some grow in temperate climates, and Britain has a few. such as the stonecrop (Sedum angli-cum, and glasswort (Salieornla europaea). The stonecrop grows chiefly on dry, stone walls and the glasswort in salt marshes. where there is a shortage of fresh-water. Only plants with efficient water storage systems could survive under these conditions. However, succulents cultivated

as houscplants originate from the warmer, arid regions of America and the Old World.

Succulent plants do not grow in absolute deserts where there is no water. However. some will survive arid regions where the rainy season lasts for only a kw weeks or even days in the entire year. Many more succulents are found in semi-arid grasslands, where the surrounding vegetation affords shelter from the burning sun. Others grow on cliffs and the rocky slopes of mountains, where any rain quickly drains away or evaporates. There are even succulents growing on the debris which collects on trees in tropical forests. Such plants are called epiphytes, using the tree only as a support, not obtaining water from it.

SUCCULENTS FOR THE HOME

The range of succulent plants in cultivation suitable for home decoration is vast, and would burst the bindings of even the largest tome. Therefore the plants described here have been selected for their suitability for most homes. However, do not be discouraged from attempting to grow a plant not mentioned. as success can be assured if the general principles described under cultivation are followed. The more difficult and rarer plants are unlikely to be found except in specialist nurseries, so there is to some extent a safeguard against attempting the almost impossible!

The Aizoaceae family

This is an immense family of plants whose members show varying degrees of succulence. All of them are leaf succulents – water being stored in thickened leaves – and the flowers superlicially resemble daisies.

Some of the hardier species have been introduced into Europe. In Cornwall and the Isles of Scilly the shrubby lampran-thus makes brilliant patches of colour in local gardens. Carpobrotus (the Hottentot ligs) are found growing on the cliffs of South Wales and Cornwall. The long, prostrate stems are covered with large sabre-shaped leaves, and they

have large, purplish flowers. I lovvever, it is the smaller, more highly succulent species which are best indoors. One of the interesting characteristics of members of the Aizoaccac family is their ‘ancestral memory’. They may be raised from seed in this country, but their growing period will be the same as their African relatives. If the rainy season in their homeland is from November to March, they will grow in the English winter. Certain species have never ever (lowered in cultivation here because the light intensity in winter is never sufficient to stimulate bud formation. Two very good species are Faucaria brit-tenae and Glottiphyllwn arrectum. These are compact little plants with fleshy leaves on short stems. Both have deep golden flowers. I’aucarias grow in the summer and flower in late summer and early autumn. They are commonly called tiger’s jaws, since the leaves have soft, tooth-like projections along their edges. C.lottiphyllums grow in late summer and flower in autumn or early winter. Outside their growing period these plants should receive little or no water.

Slightly more difficult to grow are the stone-mimicry plants, the lithops. These consist of two thick leaves pressed closely together to form a com pad.

circular or oval head. The flattened tops of the leaves vary in colour – grey. brown or fawn – and are often attractively mottled and spotted, closely resembling the stones among which they grow in their native habitat. Their growing period is our summer and the yellow or white flowers are produced in autumn. Among many attractive species are /.. aucampiae, /.. bella, and /.. helmutii.

Another group of stemlcss plants is the conophytums. growing and flowering in late summer and autumn. They have compact green heads, often prettily speckled, and a range of flower colours. Good species are C. frutescens (orange) and C. tischeri (purple). Both conophytums and lithops are plants of the more extreme deserts, and must have the maximum light possible. They need to be positioned in a south-facing window and should, preferably, spend some time out of doors during the summer. During the resting period (that is when not in growth), the plants should be kept dry. The old leaves will shrivel and new ones will develop, obtaining their moisture from the old ones. When the old leaves have completely shrivelled, revealing the bright new leaves, it is time to start watering the plants. After flowering, water less.

The Stapeliads

The family Asclepiadaceae is widely distributed over temperate and tropical regions of the world, and they are by no means all succulents. The succulent species are collectively called stapeliads. and in their native habitats are found from Spain to India. But the greatest number of species come from Africa. Stapeliads are stem succulents – the thickened stems have taken over the process of photosynthesis. Minute awllike leaves arise on the new growth of some species, soon shrivelling and falling as the stem matures. Stapeliads are found in areas where there are no bees, the flowers being pollinated by flies and have an appearance and odour to attract these insects. They are frequently of a brownish or purple colour, sometimes hairy and in some species have a decided smell of decay – hence the common name of carrion flowers. In Britain, however, few species seem to attract flies, and most have little or no odour obnoxious to human noses.

The five-petalled flowers of stapeliads have a starfish-like appearance, and some may reach a considerable size.

Stapeliads need a warm, dry atmosphere and a winter temperature of 10 deg C (50 deg F). or more. This makes many of them ideal houscplants and, indeed, some specialist growers with greenhouses will bring their stapeliads indoors in winter in order to save on heating costs. They do, however, need rather special care in watering as they have a tendency to rot if over-watered, and particular care should be taken never to allow the compost to become soggy. Huernias are small stapeliads. They are short-stemmed plants, producing smallish flowers from the base of young stems. Good species are the red-flowered H. aspera and the striped H. zebrina. Both are quite easy, but H. aspera must be the easiest stapeliad in cultivation – it appears to be almost indestructible. Stapelias themselves are probably the best known of this group and if watered carefully and not allowed to become too cold in winter they should cause little trouble. They are mostly larger than the huernias, with larger and more showy flowers. S, hirsuta (so named because of its hairy flowers) is frequently seen in cultivation. Another good plant is.V. variegata’, the spotted flowers are very striking, but it must be admitted that these in particular do have a somewhat unpleasant odour.

The Cacti

The outstanding popularity of cacti among succulent plants is to be understood, if only because of the fascination of their spiny appearance and brilliantly coloured flowers. There are over 2,000 species of these stem succulents, all native to the American continent, although some have been introduced to other warm regions of the world, where they have been growing outside for many years. Large specimens of prickly pears (Opimtin species) are familiar plants along the Mediterranean coast and Spain. Cacti may be distinguished from all other succulent plants by the presence of the areole. This is a small, cushion-like structure found on the stems and from which appear the spines and flowers. The areole is characteristic of the family, although it is not always easy to see, particularly in those species which have no spines. These spineless species, however, are in the minority, and most cacti are spined. A few of these species are so fiercely armed that handling them must be undertaken with caution. Others have only soft bristles. In general they have no leaves; some opun-tias have tiny awl-like ones on new growth, which eventually drop off. There are one or two exceptions and one rather uncommon cactus, Pereskia, has persistent leaves resembling those of a wild rose.

The flowers of cacti are usually of an open bell shape and they are always stemless (unsuitable as cut flowers!). coming in all colours except blue. Many of the night-flowering species, including most echinopsis. have white flowers with a sweet, lily-like perfume. Most cacti flower in the early summer, and although individual blooms do not last for long, a plant may remain in flower for weeks or months. There are many myths about cacti, the most persistent one being that they flower only once in seven years. This is nonsense – a mature cactus flowers annually, if well treated. But when selecting a cactus, it is important to select one which reaches maturity in a few years, not a species that does not do so until it is about 15m (50ft) tall and 50 years old. For horticultural purposes, cacti may be divided into two classes; those which grow in tropical forests, supported by trees, and the desert and semi-desert plants.

Forest cacti. These make ideal house-plants, as they grow naturally in places with partial shade. In forests they are found in pockets of leaf debris trapped in tree branches. These cacti are less succulent than those of the desert and usually have flattened stems, often segmented.

These segments are often erroneously called leaves, but they are true stems -the plants have no leaves. Very popular plants in this group are the rhipsaliclopsis and schlumbergeras. They consist of a large number of small segments. Their brightly coloured red or pink flowers are carried at the ends of segments. Rhipsalidopsis bloom in spring. R.gaertneri is popularly known as the Master cactus.

Christmas cacti are a familiar sight in florists’ shops in December, and the common name covers a number of hybrids of these winter-llowering cacti. True species are not grown, except by some specialists, but they all belong to the genus Schlumbergera. The most usual (lower colour is cerise, but hybrids exist with pink. red. and even white blooms. The most spectacular epiphytes are the epiphyllums. or orchid cacti. They have long, strap-shaped stems. At their edges.

large, brilliant flowers appear, usually during early summer. Again, true species are rarely cultivated, but there are many beautiful hybrids with flowers in shades of red. white, orange, and pink. Most of these hybrids have been given cultivar names, but it is usually necessary to visit a specialist nursery to buy named plants. The ones most commonly seen are the so-called Ackermannii hybrids. with brilliant-red flowers. These are among the easiest to grow and flower. Although the word epiphyllum literally means on the leaf, these cacti also have no leaves, only stems. All these forest cacti need more warmth and water in the winter than those of the desert types.

Desert cacti. Among the smaller-growing desert cacti which flower easily in pots are the echinopsis. They are nearly globular plants with long, tubed flowers, often sweetly scented. Good

species are the night-flowering B. eyriesii and the day-flowering E. polyancistra. Both of these have white flowers, but there are a number of horticultural hybrids with flowers in vivid shades of yellow, orange, pink, and red. Most of the echinopsis readily form offsets from around their bases.

Many of the gymnocalyciums make suitable houseplants because of their comparatively small size. G. bruchti is a genuine miniature cactus which flowers when 2.5cm (1 inch) across, producing small, pink blooms. The plant itself quickly forms a small clump, and when all the heads are in bloom it is a most attractive sight. This cactus is sometimes encountered under its older name of G. lafaldense.

The mammillarias. with their circlets of small flowers around the tops of the plants, have always been popular cacti in cultivation. There are over

species, and a ’cv specialist collectors grow no other plants. Their flowers are usually red, pink, or whitish. As a general rule, the red-flowered plants are more difficult to flower, but one exception to this is the exceedingly beautiful XL zi’ilnutnnhma, which will flower when about 2.5cm (1 inch) in diameter, and rapidly forms a clump. A good, white-flowered species is M. trichacantha. But most of these cacti are well worth trying indoors. One point to remember with them is that they always flower from the previous year’s new growth, so that if they have not grown well one year fhey will not bloom the next. Notocacti are globular-shaped and carry their usually yellow flowers on the top of the plant’s body. Most of them are quite hardy and can survive the British winter, provided they are dry during this period. Nevertheless, they can certainly be grown as houseplants. ,. nwinniu-losus, one of the best-known, is very attractively spined. and N. crassicjiblnis must have the largest flowers of any in this genus.

Ifspace is limited, the miniature rcbutias will give great pleasure. These plants will often flower in their second year from seed, when less than 2.5cm (1 inch) across. The flowers, sometimes forming a complete ring, are produced from around the base, and one of the most beautiful is the orange-flowered R. cal-Uantha var. krainz’uma. The salmon-pink flowered R. haagei, with its finger-like stems, is also very desirable. But any

rebutia is well worth growing and there are plenty to choose from. One cannot leave the cacti without at least mentioning the prickly pears, or opuntias. Most species rapidly become too large to make satisfactory house-plants. but the popular O. microdasys and its varietiesalbispina and rufida make attractive specimens when young. They may be re-started from cuttings when they become too large or straggly. The small O. spegazzinii, a species with long cylindrical stems, will flower freely in a 7.5cm (3in) pot but it does not have the elegant form of a well-grown O. microdasys. All opuntias need care in their handling because of the glochids (minute, barbed bristles) growing from the areoles. These can be particularly troublesome in the case of O. microdasys, as being spineless it appears harmless, but it is not.

The Crassulas

The Crassulaceae family is distributed world-wide, but the half-hardy specimens grown in collections come mainly from Mexico and Africa. In areas where there is little danger of frost, such as the Isles of Scilly, aeoniums can be cultivated in gardens. The Crassulaceae are leaf succulents: the thickened leaves of many species are covered with short hairs, giving them an almost furry appearance; others have a waxy coating or a white meal. The ones with a meal-like appearance often have highly coloured leaves — the colour showing through the layer of white powder – and need to be handled with great care otherwise the coating will rub oil’, leaving a permanent bare patch on the leaf. Crassulaceae

flowers are either small bells or star-shaped and arranged in clusters. The colours are mainly red. yellow, orange. pink or white.

Most crassula species in cultivation come from South Africa, but they are easy to grow and flower even under the grey skies of northern Kurope. A few. such as C. arborescens, are small shrubs. This makes a very attractive pot plant. but does need space. On a smaller scale. C. falcata with its large head of scarlet flowers has always been a popular florist’s plant. The cultivar ‘Morgan’s Beauty’ is a hybrid between C. falcata and another species. It is a true miniature and in the spring almost stemless pink flowers are formed in the centre of the rosette of leaves. The most beautiful of the Crassulaceae are the echeverias: the plants in cultivation are all Mexican. The miniature C. derenbergii or painted lady makes a delightful pot plant and is very free-flowering. A more recent introduction C. shaviana, also grows and flowers readily in cultivation. One hybrid which is not too large is ‘Doris Taylor’. This plant has beautiful furry leaves and pretty orange flowers in spring. A delightful species for a hanging-basket (although it may also be grown as an ordinary pot plant) is Kalanchoe pumila. This little specimen comes from Madagascar, and like many kalanchoes it grows and flowers during our winter and needs the heat of a living-room at this time. The whole plant, leaf and stems, is covered with a dense white meal, which makes an attractive background for the pink flowers which appear in late winter. Another plant.

really needing a hanging-basket, is the Japanese Scdum sieboldii. This has trailing stems and pink flowers, but these are produced in autumn. Possibly the most beautiful of the sedums is S. hin-tonii, with tiny egg-shaped leaves covered with white hairs, giving the whole plant a furry appearance. It also has the added bonus of flowering in the winter. This is one plant that should be watered with caution: while flowering it needs to be left dry, since this is the time when it is prone to rot. This is. of course, only a small selection of the many attractive houseplants in the family Crassulaceae.

The Euphorbias

The family Kuphorbiaceae is vast, and has world-wide distribution. There are over 400 succulent species found in the warmer parts of the world, particularly the African continent. Euphorbias are stem succulents, but they are not necessarily devoid of leaves. Some species have quite large, non-succulent leaves during the growing period; these usually fall during our winter. Those plants with fleshy, spiny columns closely resemble the taller cacti. This is an interesting example of parallel evolution. It is, however, easy to distinguish a euphorbia from a cactus-the euphorbia has no areoles, and where there are spines they are more like rose thorns. Also, all euphorbias have a milky sap which exudes from the slightest cut or prick. The resemblance to milk is only superficial – great care must be taken not to get it near the mouth or eyes, as it causes a severe burning sensation.

Euphorbia flowers are tiny, often no more than 5mm (J,in) across and usually greenish in colour, although some species have vividly coloured bracts around the flowers, giving the impression of large petals. The non-succulent poinsettia (E, pulcliemma) is a good example of this. Although many euphorbias form shrubs or even reach treelike proportions in their native state. they are slow-growing and may be kept as pot plants for many years. The crown of thorns. E. millii (formerly E. splendens), is a popular florists’ plant. and although it is scarcely succulent, it is by tradition included in collections of succulent plants. It is one of the species with highly coloured bracts, usually red but there is also a yellow form. If kept warm in winter it will keep its quite large leaves throughout the year. Two of the smaller cactus-like euphorbias are /:’. aggregate and E. submam-millaris, both South African plants. Their stems are attractively spined.

The Lily family

The Liliaceae includes many well-known garden plants, such as hyacinths, lilies and tulips, yet there are also succulent members from the drier regions of Africa. The most popular genera in cultivation are Aloe. Gasteria and Haworthia. None possess a bulb, and they are all leaf succulents. Aloe flowers are tubular, usually on long stalks and in nature are mostly pollinated by birds. The leaves, arranged in rosettes, exude a thick juice when cut. Aloe jacunda is a freely-growing dwarf plant. The best-known is undoubtedly A.

variegata, the partridge breast aloe. Aloes occur in partial shade among bushes and therefore adapt very readily to room cultivation.

Gasterias make ideal houseplants. They are small and like the shade, turning an unpleasant red colour if exposed to too much sun. The thick, shiny leaves are usually arranged in two rows. The flowers are very small (shaped like a miniature stomach, hence the name gasteria) and carried on longish stems. The plants are grown for their attractively mottled leaves and one of the prettiest is G. macuhita, with white spots. llaworthias are also small plants, most of which like partial shade. The thickened leaves are usually arranged around the stem in a rosette and the small, white flowers are carried on long. thin stems, but add little to the beauty of the plants. Many haworthias are winter-growing and these should be kept moist at that time. If haworthias are repotted during their resting period it may be found that the roots have dried and shrivelled. This is quite normal: the plant will produce new roots when it starts into growth again.

With over 160 species of haworthias. it is difficult to choose only a small number, but H. margaritifera, It. rein-wurdtii. and H. tesselata are good.

HOW TO GROW SUCCULENTS

The successful cultivation of succulent plants in the home is not very different from that of other houseplants. although for some reason they have attracted a number of myths and misconceptions about their cultivation. The poor, dried-up. half-dead specimens often to be seen on window-ledges have given rise to the idea that they are dull. ugly, and difficult plants. Nothing could be further from the truth, and if given reasonable attention they will thrive and flower well, and continue to do so for many years.

Composts

While any old, hard soil will not do. succulent plants are, in general, quite tolerant about their compost. The main essential is that it should be well-drained and never waterlogged – but this applies to most houseplants. There is no need to buy special compost for succulents. John Innes potting compost No. 2. or a peat-based loamless type are suitable for most plants, including succulents. A few succulent enthusiasts like to mix about one-third of sharp sand or grit into the standard compost to improve the drainage, and this is an advantage if it is convenient to do so, but is by no means essential.

Potting and potting-on

Florists sometimes sell cacti and other succulents in what are somewhat unnecessarily called cactus pots. The feature of these is that they are small. Any plant bought in a pot less than 5cm (2in) in diameter should be potted-on at once into one of at least this size, since the very small pots dry out too quickly and give virtually no root room. The most popular pots are plastics, but clay pots are quite suitable, the main difference being that plants in plastic pots need less frequent watering than those in clay ones. Although it is possible to grow succulents in decorative pots with no drainage holes, it is not advisable unless the grower is very experienced and careful with watering. If decorative pots are required it is better to use them as outer containers for conventional pots. One piece of broken pot over the drainage hole is all that is needed for a clay pot. Nothing is needed for a modern plastic type, which normally has a number of small holes.

When to pot-on

A vigorously-growing plant will need potting-on annually, others can spend two years or so in the same pot. [f there is any doubt, it is merely necessary to remove the plant from its present pot and examine its roots. If tightly packed around the sides, the plant should be replaced in a size larger pot. and fresh compost added. Otherwise, as much old compost should be shaken from the roots as possible, without damage, the pot thoroughly cleaned and the plant replaced. again with fresh compost added as necessary. Spiny plants, such as most cacti, can be gently held in a folded strip of newspaper whilst handling for potting.

Watering succulents

The successful watering of succulent plants is much the same as for other houscplants. In spring and summer. soak thoroughly and do not water again until the compost has almost dried out. and never allow the pot to remain standing in water. The difference is that these plants will usually survive even if watering has been neglected. But they will not grow and thrive under such treatment if prolonged. It is impossible to say just how often water is needed, as this will depend upon the conditions in the room. Generally, much less water is needed as winter approaches. Most cacti prefer to rest during winter and their pots should not be soaked at this time. Instead, just dip the pot in water every few weeks to prevent the compost completely drying out. If this happens, the line root hairs will be destroyed, delaying growth in spring. Exceptions here are the Christmas cacti and other forest cacti (rhipsalidopsis and epiphyllums) which need to be reasonably moist at all times. Other succulent plants can be given a little water in winter, particularly if the room is warm and the plant appears to be still in growth.

The rather specialized watering of the lithops and conophytums is mentioned under their section of the Aizoaceae family.

The best way to water all these plants is to stand the pot in water until the compost is quite wetted, and then remove and allow to drain. With a large collection, this is not practicable and plants will have to be watered from above, taking care not to wet the leaves.

Situation

just where in the room to keep succulent plants is important. Apart from aloes, gasterias and haworthias. and the forest cacti, which all prefer some shade from

the summer sun. they should be put in the sunniest window possible, which means that north-facing windows are really not suitable, except for the plants just mentioned. Because window light is one-sided, the plants should be turned every few days to prevent them showing one-sided growth. If possible, put your plants outside in the open during late spring and summer, as direct sunlight is beneficial – but still remember those with a preference for shade. Plants should never be placed near a radiator.

Temperature

Normal room temperatures during spring and summer will suit succulent plants if they are kept inside at this time. During winter, however, most cacti prefer a colder rest and if they can be transferred to an unheated room they are likely to flower better the following year. But. if no cold room is available or. as is quite natural, you want to keep all your plants in the living-room to cheer you in the winter, it would be unreasonable to suggest otherwise. But if a cactus which should flower well fails to perform, it is worth trying a colder situation the following winter. The forest cacti, together with the rest of the succulents, can certainly be kept in the living-room in winter.

Feeding

All succulent plants will appreciate a fortnightly feed while in active growth. and those growing in a loamless compost will need regular feeding, since the soil nutrients are quickly exhausted. Liquid feeds should be high in potassium, such as those used for tomatoes.

Pests and diseases

There are really no pests specific to succulent plants, but any pest affecting other houseplants can also affect them. The most common are mealy bugs and root mealy bugs. These can be controlled most effectively by proprietary systemic insecticides, used strictly according to instructions.

The most common disease is rotting of the stems or roots, usually due to over-watering or poorly-drained soil.

Propagation

Cuttings and offsets. Most succulents can be propagated from cuttings, although some root more readily than others. One general principle which must be observed with cuttings of all these plants is not to pot up immediately. but to allow the cut end to dry for a period of a few days to a week, depending on the area of the cut. to allow a callus to form – otherwise there is risk of rot. They

can then be potted up in a sandy compost or a peat and sand mixture, and kept slightly moist.

Once new growth starts, it can be assumed that the cutting has rooted. The best time to pot it is during the active growing period of the plant, usually spring and summer. The actual method of cutting obviously depends upon the type of plant. Usually a piece of stem 5-10cm (2-4in) long is about the right length. Long stems, such as those of epiphyllums, can be cut into smaller portions, each of which should root and send up fresh shoots.

In the case of segmented stems of plants. like the Christmas cacti, a portion consisting of one or two segments is chosen. One segment or pad of an opuntia will usually root.

Succulent leaves, such as those of eche-verias. will often take root if gently pressed into the compost, or even laid upon it. Luphorbias. with their milky latex, are rather difficult – the cut ends should be dipped into water to clear the latex before the usual drying-olT. Many cacti, notably echinopsis and mammillarias. readily produce offsets which can be carefully removed, if overcrowded, and used for propagation. If the offset can be pulled away, without actually cutting, it can be potted into a pot of compost straight away.

Raising from seed. Seeds of succulent plants are often available and should be sown in a seed compost. Most seeds are small and should be scattered over the surface of the compost – larger ones are pressed into the surface. A glass or plastic cover is needed until germination starts. The seed container is best watered from below, the compost being kept moist, but never waterlogged. A temperature of’21-25 deg C (70-77oI;) is necessary for good germination and if this can be maintained. March or April is the best time. Alternatively. it is advisable to wait until June. Light is not needed for germination but as soon as the young seedlings appear, in about 10-14 days, they must be exposed to diffused light, but not direct sunlight. The glass or plastic cover should be removed.

Young succulents can usually spend a year in the seed container before being transplanted. Do not expect all of the seeds to germinate. Commercial seed is not always fresh, and stale seed germinates badly or not at all. However. usually at least some plants will result and raising these plants from seed is so fascinating and economical that it is well worth the effort.

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