How to Look After Cacti and Succulents
Cacti may be planted out in beds from June to September. If they are removed from their pots it may be quite impossible to put them back in the same sized pots in the late summer or autumn. They may be left in their pots, but thehole must be freed from when they are removed. A few cacti may stand the cold of winter out of doors, but a very severe winter would probably kill them. If the grower wishes to experiment, he should make sure that any cacti left out during the winter are those which can be parted with, and not specimen plants.
All the spiny types of cacti can stand plenty of sunshine as long as there is plenty of air available in a greenhouse. The epiphytes benefit from shade during the hotter months of the year, and may be stood outside the greenhouse provided no frosts are forecast. Cacti kept in windows of the house must be where they can get the maximum amount of light and they will not flower well unless they can get a fair amount of sunshine.
Most cacti flower in spring, summer or autumn, and it will be found that many flower on new growth only. If theare pollinated many colourful seed pods can be formed. On the mammiliarias these pods can look very attractive.
Pests that Affect Cacti
If cacti are grown well they suffer little disease but there are a few pests which may attack a sick plant. The most frequent is the mealy bug. This appears in a small tuft of wool or powder. Scale may also attack some cacti and looks like a small scab. Red spider may be a nuisance if the atmosphere is too dry. All these pests can be killed with malathion, used as directed on the bottle.
Cultivating other succulents
Most succulents thrive in the same conditions as given for cacti, so it is only necessary to give the few exceptions special treatment to be able to grow them all in one greenhouse. Those which may present some difficulty in a mixed collection are the ‘mimicry’ types which are found in South Africa. Many of these have a particular resting period and unless this is copied in cultivation it is probable that the plants will grow out of character. Those mimicry plants of the mesembryanthemum group, such as lithops and conophyturns, are better placed by themselves in the greenhouse where they can be given specially required treatment with regard to watering, etc. Some succulents do not require as much direct sunshine as others. It may be possible to site these in the greenhouse where they are able to get partial shade, perhaps from taller-growing plants.
Some of the plants which do not do too well in direct sunshine are the gasterias and haworthias. These turn very red or bronzed and may cease to grow in too much sunshine. In their native habitats they do not grow in the hot, dry season. It is only when the rains come that they make any new growth and flower. It is probable that in some regions where many succulents grow there may be no rainfall for a year or two. Some types of succulents grow among coarse grasses or low shrubs, where they get a certain amount of shade.
If the natural conditions of their native habitats are understood it will be easier to provide the necessary treatment for the successful growth of succulents. However, although these plants grow in so many different climatic regions, and in spite of the special treatment required by some types, it is possible to grow most kinds quite successfully by the same method of treatment, and in the same soils. Soil and compost Most succulents are not at all particular as to the type of soil they are grown in provided it is porous. Many can be grown in almost pure sand, while some grow better in a fairly rich compost as long as the surplus water can drain away fairly quickly.
It is sometimes recommended that a special soil is used for each genus, but it is possible to grow a varied collection by using one soil only. If you have a large number of plants to pot up, you will no doubt like to mix your own soil, but where a few plants only are to be dealt with it is far easier to buy a reliable potting compost and add a little extra roughage to make up a suitable compost, or make your own as given previously for cacti.
The standard commercial potting composts have a larger proportion of loam and peat to sand than has the mixture recommended previously. Although this is excellent for ordinary plants it will be found that it holds too much moisture to be suitable for the succulents. Some need a more porous soil than others, but by adding the necessary roughage, such as grit, broken brick or charcoal, it is possible to use commercial composts for all types.
By adding the extra roughage the proportion of fertilisers will be lessened; but few succulents require a rich compost. If a compost is used which is too rich in added fertilisers it is probable that the plants will grow out of character. They may then become soft and sappy and succumb to cold, wintry conditions.
The time for repotting succulents depends on the type. As with the cacti, other kinds that have a resting period should not be repotted until growth has begun. Normally March would be the time for this task but the genus may be resting then and so must wait for a few months before being repotted. Most succulents will probably benefit from a repotting at least every two years. Any plant in a small pot which is watered occasionally will have used up most of the nourishment in the soil and so will need a change. Some of those that grow more rapidly can be repotted once a year. If the plant growth reaches the side of the pot a larger pot is needed. It is important to be able to inspect the actual soil in the pot to make certain whether the plant needs watering. All the old soil must be discarded. A good crock should almost cover the drainage hole of the pot, the larger it is the easier it will be to remove the plant when repotting again becomes necessary. The compost should be crumbly moist when potting is done, and then, as with cacti, no water need be given for a week or so.
Once watering is begun in the early part of the year enough should be given each time to ensure that all the soil in the pot is well damped. It may be necessary to go over all plants again to ensure that enough has been given.
The secret of watering all succulents is to refrain from giving any more water until the soil has dried out. Remember succulents will not survive for long in asoil, so adequate drainage is essential.
Some succulents can be raised from seed and soon make sizable plants, others can be propagated by division or by taking cuttings. Many of the succulent-leaved types can be increased by taking off the leaves and rooting them in sharp sand. Where this is done the leaves should be just laid on the surface of the sand. If leaves or cuttings are pushed into the sand too deeply rot may set in causing failure to root.
Summer and winter treatment
Some of the succulents which do not like excessive summer heat in the greenhouse may be placed out of doors from June to early September. They must be protected from slugs, etc. Water them occasionally during dry weather. If these plants are bedded out for the summer it will be difficult to repot them into the same sized pot when they will be removed.
Most succulents can be kept at 40-45 °F (4-7°C) through the winter provided the soil is dry and they can stand any temperature they are likely to encounter during the summer.
Miniature succulent gardens
Cacti and other succulents are very suitable for miniature gardens. For impact, they will depend mainly on dwarf plants, some of which may be miniature replicas of their taller counterparts while others will display their own individual characteristics.
A good way of getting horticultural quarts into pint pots is to garden in sinks and troughs. Several of these plant containers, each with its separate planting scheme, can be accommodated in a minimum of space. Many a town forecourt, backyard or balcony could benefit from the inclusion of a feature of this kind.
Unfortunately, genuine stone troughs and sinks are fast becoming collectors’ items and, in consequence, increasingly difficult and expensive to come by. The stone sinks of Victorian kitchens and sculleries have long ago been replaced by vitreous enamel and stainless steel, while the larger troughs, formerly used for watering cattle and horses, have given place to galvanised iron tanks.
The occasional specimen still turns up at country sales and in junk yards, but dealers are aware of their value and prices have risen astronomically. As an alternative, concrete or old glazed sinks can be adapted for the purpose. But neither of these will have the charm of the genuine article which, if it has been out-of-doors for any length of time, will be weathered and decorated with mosses and lichens.
Particular attention must be paid to drainage before planting up any of these containers. A piece of perforated zinc should cover the existing drainage hole and the base of the trough or sink should be covered with broken crocks or stone chippings to a depth of 2-3 inches. On top of this goes a layer of peat moss or chopped turves, the latter grass side down.
The planting mixture should consist of the same compost as given above for repotting. Only half fill, then when the plants are in position the rest of the soil may be added and firmed. If the soil under a flat stone, pressed into the top of the soil, is clamp do not water.