How to Propagate Conophytum by Division and from Seed

Three routes, and how they compare

Conophytum offer more options than most of the stone-plant group because a healthy plant naturally builds into a clump of many heads over the years, and that clump can be split. Division gives you a flowering-size plant immediately and is the method most growers use. Seed is slow but cheap and produces far more plants than you will have room for. Detached heads without roots are possible but unreliable, and there is no leaf-cutting route at all.

Timing is the same for all of them and follows the plant's own calendar: everything happens at the wake-up and through the cool growing months. Nothing useful happens during the hot rest, and attempting any of these in the heat wastes both the material and the season.

Dividing a clump

A clump that has filled its pot is ready. Do the work dry, at the wake-up when the new heads are beginning to swell, so that the divisions root away immediately rather than sitting inert. The aim is pieces of three to five heads, each with its own share of the root system and a bit of the woody base holding them together.

Turn the plant out and comb the mix away until you can see how the branches of the old stem connect. Most clumps come apart along natural lines with gentle pressure, and where they do not, a clean cut through the woody base is fine. Keep the blade sterile and cut through wood rather than through anything green.

Let the divisions dry in open air for two or three days so the cut surfaces seal, then pot each one into a gritty mix at the same depth it grew before, with the base of the heads at the surface. Hold them dry in bright shade for another week, then water normally for the season. Expect a little shriveling for a fortnight; it passes as the roots take hold.

Pieces that came away with no roots at all should be treated as detached heads rather than divisions. Sit them on the surface of a barely damp gritty mix, do not bury them, and keep them shaded and out of direct sun. Some root within a few weeks in the cool season, and the ones that do not simply dry up and are no loss.

Never divide a clump in flower or during the hot rest. In flower you lose the display and the plant drops buds; in rest the pieces have no root activity to heal with and most of them rot before the season turns.

Getting and sowing seed

Most of these plants need pollen from a genetically different plant to set seed, so a single specimen on a windowsill will flower year after year and produce nothing. If you have two unrelated plants flowering at once, move pollen between the open flowers with a fine brush on two or three consecutive days and you will usually get capsules. Flowers of many kinds in this group open in the evening and are scented then, which is a useful hint about when to do the work.

Capsules ripen and dry on the plant, and the seed inside is extremely fine, closer to dust than to a seed you can count out. Collect the dried capsules, break them open over paper, and store the seed dry and cool until sowing time. Seed keeps well for a year or two.

Sow as the weather cools at the start of the growing season, which gives the seedlings the whole cool stretch to establish before their first hot rest. That first summer is the dangerous one, and a seedling with only a few weeks of growth behind it rarely survives it.

1. Prepare a fine-surfaced pot Fill a small pot with the usual gritty mix and top it with a quarter inch (6 mm) of finer sieved material so the dust-fine seed has something to sit on. Soak the pot thoroughly from below and let it drain before sowing.
2. Scatter the seed on the surface Sprinkle the seed thinly across the top and do not cover it at all. These need light to germinate, and any covering at all will stop most of the seed. Thin sowing matters more than it seems, because crowded seedlings damp off together.
3. Keep it humid and shaded until germination Cover with a clear lid or a bag with a gap for air, and keep the pot in bright shade at around 60 to 70F (15 to 21C). Keep the surface constantly slightly damp. Germination usually starts within a week or two and continues over several weeks.
4. Ventilate progressively Once most seedlings are up, open the cover a little more each week over about a month until it comes off entirely. Sudden exposure to dry air kills seedlings that have never known it; gradual exposure toughens them.
5. Keep seedlings growing through their first summer Unlike adults, first-year seedlings are not given a completely dry rest. Keep them lightly and occasionally moist through the first hot season, in shade and good airflow, so they are large enough to survive the second one on adult treatment.

The first years, and what to record

Seedlings are single heads the size of a pinhead in their first months and look like nothing at all. By the end of the second growing season they will be recognizable small bodies, and somewhere in the third to fifth year they begin to divide into clumps and to flower. Prick them out into their own pots at the end of the first year or leave the pot as a communal one for two years; both work, and the communal pot dries more evenly.

Give seedlings less light than adults. The bright but softened light that suits mature plants is still too much for a first-year seedling, which burns easily. Shade them more heavily and step the light up over the second and third years.

Keep a record of the sowing date, the germination date and how many came up, along with the date you first reduced water for a seedling batch. The gap between sowing and the first flowering is measured in years, and without notes it is impossible to reconstruct which batch a given plant came from or what treatment produced the ones that survived. For divisions, note the parent plant and the date of the split, since divisions that struggle usually trace back to being taken too small or too late in the season.