Blossfeldia liliputana
| Light | Bright, indirect light; protect from scorching direct sun |
|---|---|
| Water | Very sparingly; keep dry in winter, water carefully in growth |
| Soil | Fast-draining, mostly mineral mix (see Soil and potting mix) |
| Temperature | Keep above freezing; frost-tender, USDA zones 9b–11 |
| Propagation | Seed (primary); grafting to speed and ease cultivation |
| Toxicity | Non-toxic to cats and dogs |
Blossfeldia liliputana is the smallest known cactus in the world, a tiny spineless button that seldom exceeds about 12 mm across and grows wedged into cracks and crevices on rock faces in the Andes of South America. Its minute size and unusual biology make it a prized curiosity among collectors, and because it is so slow and demanding on its own roots, it is very often grafted in cultivation. It is the sole and defining species of the genus Blossfeldia.
Description
Blossfeldia liliputana forms a soft, flattened, greyish-green disc without ribs, spines or obvious tubercles — a smooth little button pressed against the rock. Individual heads are usually only a few millimetres to just over a centimetre wide, and older plants slowly clump into small cushions of many crowded bodies. The areoles are tiny and woolly, arranged in a loose spiral over the surface, and a slightly sunken growing point sits at the centre.
The plant is remarkable botanically as well as visually. It is one of the most desiccation-tolerant of all flowering plants, able to shrink down and dry almost completely during drought, then rehydrate when moisture returns. Small whitish to pale-yellow flowers, only a few millimetres across, open from near the crown and are followed by tiny fruit and dust-fine seed.
Distribution and habitat
The species is native to the Andean regions of northern Argentina and Bolivia, where it grows at moderate to high elevations. It is a true crevice dweller, rooting in narrow cracks on cliffs and rock outcrops with almost no soil, often on steep or vertical faces where rain drains away instantly and moisture arrives mainly as mist, dew and brief runoff. There it endures intense light, wide temperature swings and long dry spells, surviving by drying down to a shrivelled disc between rains.
Cultivation
Blossfeldia liliputana has a reputation as a challenging plant on its own roots, largely because it is extremely slow and intolerant of stale, wet compost. Grow it in a very free-draining, mostly mineral mix in a small pot, give it bright light with some protection from the harshest midday sun, and water sparingly — a light watering once the mix has dried, then patience. Keep it completely dry and cool through winter to avoid rot.
Because seedlings are so tiny and grow so slowly, many growers graft them onto a vigorous rootstock such as a Pereskiopsis or column cactus; grafted plants grow far faster, clump readily and flower more freely, though they take on a plumper, less natural look than wild-collected specimens. See Watering and Repotting for general technique, and take special care never to bury the little bodies too deeply.
Propagation
Seed is the standard method, but the seed is exceptionally fine and the seedlings minuscule, so germination and early growth demand patience, warmth, humidity and a very careful hand with watering. Some growers sow onto a mineral surface and keep humidity high under cover until the tiny plants establish. Established clumps can also be divided, and individual heads are frequently used as grafting scions to bypass the slow seedling stage. See Propagation — seed for a full walkthrough.
Common problems
- Rot — by far the biggest risk; overwatering or a slow-draining mix quickly kills these crevice plants, which softens and browns at the base.
- Loss of tiny seedlings — seedlings are so small that they dry out or damp off easily; steady humidity and gentle watering are essential in the early stages.
- Pests — mealybugs (white fluff in the areoles and among clustered heads) and root mealybugs can hide in the tight cushions; watch also for red spider mites in hot, dry conditions.
See also
- Blossfeldia — the genus overview
- Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting