The Ampyx Cactus Centre

The Cactus of the Month feature is brought to you from Ampyx's own greenhouse, and tries to illustrate the wide variety of cacti that may be cultivated in very modest surroundings. The images are (where possible) topical for the month. Ampyx has been growing cacti since the late sixties, but does not pretend to be an expert - just someone for whom some cacti will grow and flower................

Mammilaria microhelia
Mammilaria microhelia
Where to grow cacti?
A sunny windowsill is the place where most collections start. Take care that your poor little plant isn't scorched by the hot sunshine - behind glass and without ventilation it can get really fierce. Apart from the taller-growing 'organ-pipes' and 'barrels', few grow away from the protection of other plants or grasses. So long as there is some broken shade for some of the day your south-westerly windowsill will be OK. Make sure that it won't freeze in Winter.

The major drawback is the curtains. My mother soon started to complain about the spines which got caught up and transferred to her person, and the complaint was echoed some years later by my girlfriend. Try a small staging at the end of your greenhouse, among the tomatoes. They won't mind, honestly......

During the frost-free months a cold frame can be an ideal solution. Cacti are not especially fond of heat, so leave the lights open in fine weather, and use them just to keep off the rain in wet weather. The all-round illumination will give much better results than the windowsill.

Which cacti to grow?
Ampyx's first plant, over 30 years ago came from Woolworths and cost 1/11d (that's less than 10p). It was pretty, prickly, hairy and was quite happy until it was stolen in 1975, along with most of the collection. For windowsill or casual culture, I would avoid any plant whose name ends with -cereus. Mostly those are the kind that grow to the stature of slim trees in the wild, and will fairly rapidly outgrow your windowsill, if given a chance. Under 'windowsill' conditions, most will become 'bonsai' subjects constrained by the lack of space to spread their roots and reach out for the big time. For the same reason, avoid the sort which have rounded pads covered in more-or-less-detachable, tenacious (and intensely irritating) spines. Neither of these groups will flower under such conditions.

Stick to the blobby sort. The globular varieties tend to be smaller, happier, less likely to attach themselves to the curtains (with exceptions, of course) and more likely to flower. Most of the plants pictured are very undemanding, tidy specimens and growing them isn't rocket-science. Try Mammilaria, Rebutia and Notocactus for starters......Visit the gallery to see examples that have appeared on these pages, and notes on their cultivation.

Gymnocalycium bruchii
Gymnocalycium bruchii
Rat-tail hybrid
Aporophyllum 'Sussex Pink'
What funny names they have!
Cacti, which all originate in the New World, were fairly recently discovered by Europeans, and mostly they were described by botanists who used the 'Latin' systematic names of the Linnaean system. If the native Americans had individual species names for the plants, I do not know. My guess is that they were much of a muchness to them, seldom being of any value or interest. Those that were psychoactive (for example) certainly had names! Some good descriptive names are applied to certain notable species, such as the Jumping Cholla whose detachable joints will cling magically to any unfortunate animal that brushes past. On the other hand, Claret Cup Cactus doesn't help anyone.

Gardeners can be perfectly at home with Impatiens (Bizzy Lizzie), or Fuchsia, or even Berberis atropurpurea nana, so the cactus names are not so bad. Think of the first name (always capitalised) as the family name, and the second (never capitalised) as the personal name i.e. Smith john. Some names have a third, extra part to describe unusual forms, colours or hybrid origin. That was easy! Sadly, plant names are often missing or incorrect, even in good garden centres......

When do I water them?
Cacti do not live in deserts, but in areas with sporadic or seasonal rainfall. Many live in grassland or among other drought-tolerant shrubs. Some even live in the canopy of moist forest - the epiphytic types (including the famous Christmas Cactus). They most certainly need water, but are happy to go without for more or less extended periods. What is of paramount importance is never to allow them to be waterlogged, for then they will surely start to rot, lose their roots and die.

Ideally the compost in which they are planted should be freely-draining, which means that it will hold water but will not become sodden. Gritty, peat-based composts are ideal, and well formulated soil-based compost such as John Innes number 2 will work well with an extra dose of gritty sand. Regular multi-purpose composts are too moisture-retentive for the modest requirements of most cacti.

The trick is to ensure that the compost is on the dry side before watering again, and that will depend upon the time of year. In our dark, damp, cold winter the plant will become inactive, and needs only enough water to keep its roots alive - so reduce the watering drastically. In Spring the plant will wake up with the lengthening days, take up water into its shrivelled tissues and resume growth. If you are lucky, it will also start to produce flower buds and do its best to reproduce before the the drought returns......

Weingartia hediniana
Weingartia hediniana