The way to success with succulents

Press, 20 November 1981, Page 10

The way to success with succulents

GARDENER’S 1 W DIARY

Derrick Rooney

One of the most rewarding groups of plants this year has been the succulents, including cacti, of which I have a very small but to me very interesting collection, not chosen in any systematic way but simply an assemblage of plants that I have liked for their form, texture, or flowers. Often, I wonder why more people do not grow them, for there can be no group of plants more easy to please and more difficult to kill by neglect. It can’t be because of the prickles, because roses have nasty thorns too, and roses are the world’s most popular flower. It can’t be because of lack of flower power either; when people complain that their cacti never flower it is because they have been trying to grow the wrong ones. My experience has been that there are numerous small cacti that are very easy to grow and flower; some of the lobivias and rebutias will flower in their second or third year from seed. They have showy, brightly coloured flowers, and there is plenty of contrast in them, even though the range is effectively restricted to variations on red and yellow. Rebutias especially are easy to flower, do so very early in the season, are fairly hardy, and grow well in pots. My specimens live year-round in a cold frame which is freely watered in early and late summer, but kept dryish in midsummer and completely dry from April to September. The only additional protection they get is an old carpet which is flung over the lid on cold nights, and sometimes even with this protection the soil in their pots is frozen solid on really frostv nights. But losses are generally light, and last winter I didn’t lose anything. You can get plenty of complicated advice out of books on watering and fertilising cacti, but I don’t have time to go round watering and feeding my multiplicity of potted plants individually,

and I do all watering by sprinkler, which is completely contrary to the ad-' vice given in my cactus books. Obviously the plants have not read the books, because a variety of succulents — by no means all cacti — is • thriving, so much so that their frame, which is 2m square, is in danger of severe over-population. , The pots, most of them not much bigger across than the plants they contain, are plunged, to keep the roots cool, in rotten sawdust, which is not, the ideal medium (grit or sand would be better) but has the advantage of being easily obtainable and costing nothing, whereas for me grit isn’t, and doesn’t. The advantage of a plunge — whether it be sawdust, grit, or any other porous material — applies equally to all plants in pots: it insulates the pots against sudden fluctuations of temperature which can damage, even destroy, roots. It also conserves moisture and reduces the amount of repot- ’ ting that has to be done — roots work their way out of the drainage holes and spread widely through the plunge material, so that they have much more tolerance of drought. Of course, it is heretical to say you should let this happen, because most of the books say you shouldn’t, but in practice I have found it the only way to maintain my succulents in good health. Their’ frame is about 80cm high at the front, rising higher at the back, and the sawdust plunge occupies about 50cm of this depth, so they have plenty of room to run about — some plants root themselves so, firmly into the sawdust that I can’t lift the pots out.

I give my succulents shade, too. The association of cacti and deserts is deeply embedded in the public mind, but it is fallacious to believe that all cacti need sun and drought. Some of them come from rain forests. True, the large species, such as the giant saguaro of Arizona, spend their mature years basking in the desert sun, but small cacti and seedlings almost without, exception need shade. They do mostly grow in arid or semiafid areas, but even the wild plants will seek out whatever shade is to be found beneath scrub, or grasses. I learned this the hard way when part of my collection (maybe the best, part) was cooked one hot day. Even the corrugated fibreglass material with which I now cover my frames (glass is too vulnerable) has to be shaded; it looks semi-opaque, but light transmission through it is high enough to scorch. The old method of dealing with this problem was to put on a thin coat of whitewash in spring; by the time the autumn rains had washed it off the sun was weaker and shade was no longer needed. Whitewash is not so easy to come by now, .but white acrylic paint , makes a good substitute. Seven or eight parts of water to one of paint is my mixture, arrived at by trial and error; it works well. It is not at all messy to handle, it spreads easily, and if you have a big area to cover you can slop it on with a soft broom. This seems to provide just the right amount of shade, and nearly all my succulents look healthy, flower freely, and colour well. They get no special treatment, other than having their own house, and I gave up making special potting mixes fbr them years ago. Some weird and wonderful mixtures have been propounded by experts — with such ingredients as old cowdung and crushed mortar — but my succulents grow in the same mix as all my

other potted plants, whether they be rhododendrons, alpines, or bulbs; equal parts of sand, peat, and my old friend rotted sawdust, plus a dash of dolomite and, if I’m in a good mood, some trace elements. All the major nutrients are provided by a proprietary slow-release fertiliser that I add to the mix — it remains effective for months. I have never been able quite to come to terms with plastic pots, and I still use mostly unglazed clay ones, and water frequently in hot weather. A couple of experts who visited my garden recently told me I am doing everything wrongly, but my answer to them was that the plants look : healthy, flower well, and obviously haven’t read the rules. I do not even, as some people do and many experts urge you to do, waste space in the bottom of the pots on drainage material. A single piece of broken crock, or a flat stone over the drainage hole, is all that I use. It is only there to stop the soil from falling out; the drainage is in your compost, and if your mix is badly drained no amount of crocking will help. A number of cacti, thus erroneously cultivated, are in flower in my frame now. Some spectacular notocacti and echinocereus are in fat bud, but the most prominent at present is the tiny Rebutia icthyacantha, a pool of. molten orange. Sulcorebutia breviflora, bronze-bodied and even smaller, is a wash of chrome yellow flowers, shading on the exterior to hot pink. Rebutia senilis is coming out red all over and Echinnocereus melanocentra has had two huge pink flowers already, and more are to come. The star performer last week was a lobivia, with glossy fuchsia pink and red flowers, each with a white eye and a boss of yellow stamens. This was supplied as Lobivia pentlandii, which it is not — the true thing has orange-red flowers. But that is not surprising because most of the rebutias in cultivation are not true to name, and many are hybrids. The genus has very low morals and if there is another plant nearby with which a lobivia can hybridise it will do so. There was great excitement one day when I acquired a plant of the rare Lobivia emmae, which has cool orange flowers — and corresponding disappointment later when the flowers opened: bright red.