Astrophytum Myriostigma Tricostatum Description: Astrophytum myriostigma var. tricostatum is a strikingly pretty, old cultivar with only three ribs with light or dense white flecks that cover the stem. Nude plants (see) are also known and very appreciated. This cultivar tends to be unstable, and some of the three ribbed specimens develop additional ribs as they age. Old and big plants which maintain the typical three ribbed shape are very very prized.
Flowers: arise from the areole at the tip of the stem on mature plant (at least 4-5 years old) they are large, funnel-shaped, yellow, 5-7 cm wide. Blooming intermittently throughout the warm months from spring to autumn.
Cultivation and Propagation: Although regarded as a choice and difficult plant in cultivation it is relatively easy to grow. It is sometime seen as a grafted plant but grows very well on its own roots too. Use mineral well permeable substratum with little organic matter (peat, humus). The Astrophytum myriostigma grows much faster with a low nitrogen content fertilizer in spring and summer. Water sparingly from March till October, the thin, fibrous roots suffer if there is humidity, therefore the plant should be watered only when the surrounding terrain is dry. Keep dry as soon as the temperature starts dropping in October and keep it perfectly dry in winter at temperatures from 5 to 15 degrees centigrade. (but it is Hardy to -7°C for short periods) Although it is one of the easier Astrophytum to grow, they tend to rot at that time of the year, if kept wet. In the rest period no high atmospheric humidity!! Sun Exposure: Light shade to full sun, its colour tends to richer and darker when grown in light shade.
Propagation: They can be propagated easily from seed or graft. Seed Collecting: Allow unblemished fruit to ripen; clean and dry seeds. Properly cleaned, seed can be successfully stored. Plants are sometimes grafted onto column-shaped cacti. Cutting scions from a flourishing plant is almost a crime because the scions do not root easily.