# # # PIANTA SPECIALE # # # (Esemplare selezionato)
Diametro 8 cm; innestato su Opuntia humifusa.
Family: Cactaceae (Cactus Family)
Scientific name: Astrophytum myriostigma Lemaire cv. ONZUKA f. quadricostatum (4 ribs form)
Original description: Cactacearum Genera nova Speciesque novae et omnium in Horto Monvillano cultarum: 4-6 1839
Conservation status: Listed in CITES appendix 2.
Origin: Japan, Garden origin (Nursery produced cultivar)
Astrophytum myriostigma f. quadricostatum.
Description: Astrophytum myriostigma cv Onzuka "quadricostatum" with only four ribs - is one of the most sought after cacti, that have fabulous markings much like the ‘kabuto’ asterias. There is a variety of variations in ribs shape and in stems markings.
This cultivar tends to be unstable, and some of the four ribbed specimens develop additional ribs as they age. Old and big plants which maintain the typical four ribbed shape are very prized. If you are so inclined you can pay large sums of money for some of the best Japanese forms.
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: 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). Water sparingly from March till October and keep perfectly dry in winter at temperatures from 5 to 15 degrees centigrade. (but it is Hardy to -7°C for short periods) In the rest period no high atmospheric humidity!! Sun Exposure: Light shade to full sun.
Be careful: The epidermis of ONZUKA is harder than in the normal myriostigmas and cracks easily if plants are overwatered.
Propagation: By seeds, remembering that seedlingsdislike strong light and dry conditions and need to be repotted frequently. Eventually, as they become mature, they attain a maximum size of 8-10 cm (20) cm in diameter. However, old plants become senile and have a tendency to succumb to disease and a weak root system. At this stage, as is well known, they die suddenly. So, after they reach 10 cm in diameter grow them slowly, and adopt a new repotting period, using intervals of every 2 - 3 years. Additionally grow them under drier conditions or with stronger sunlight.
But plants are often grafted to accelerate growth as they would generally take at least a five years to reach maturity on their own, but the grafted plants are typical rather tall growing, compared with plants on their own roots that are usually more flat to the ground.