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Astrophytum asterias cv. Rensei

Family: CACTACEAE · Cultivar of Astrophytum asterias

Publication: ( = Line Areoles )

Description

“Rensei” means ”Chain of areoles”. The areoles on the ribs are very close and forms an unbroken line, a chain of areoles.

Origin and Habitat

Japan, Garden origin (Nursery produced cultivar)

Cultivation and Propagation

Astrophytum asterias is a summer grower plant relatively easy to grow. It is sometime seen as a grafted plant but grows well on its own roots too. It is not too difficult in a greenhouse, although grows slowly.

Soil: Use mineral well permeable substratum with little organic matter (peat, humus), plants may become too elongated if compost is too rich.

Repotting: It needs to be repotted frequently. Eventually, as it becomes mature, it attain a maximum size of 8-10 cm (20) cm. 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. Use pot with good drainage.

Fertilization: It grows much faster with a low nitrogen content fertilizer in spring and summer. Potassium helps maintaining the plants compact and healthy.

Watering: Requires careful watering to keep plant compact. 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.

Hardiness: They need to be kept in a cool place during winter rest and are somewhat resistant to frost if kept on the dry side prior to, and during, cold weather (due to the altitude they are hardy to -5 C ° C, or less for short periods). It tends to rot in winter during the resting phase, if kept wet. In the rest period no high atmospheric humidity!!

Sun Exposure: It needs a good amount of light. Light shade to full sun, its colour tends to richer and darker when grown in light shade.

Uses: It is an excellent plant for container growing. It always looks good and stays small.

Pests & diseases: It may be attractive to a variety of insects, but plants in good condition should be nearly pest-free, particularly if they are grown in a mineral potting-mix, with good exposure and ventilation. Nonetheless, there are several pests to watch for:

- Red spiders: Red spiders may be effectively rubbed up by watering the infested plants from above.

- Mealy bugs: Mealy bugs occasionally develop aerial into the new growth among the wool with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.

- Scales: Scales are rarely a problem.

- Rot: Rot is only a minor problem with cacti if the plants are watered and “aired” correctly. If they are not, fungicides won’t help all that much. To prevent rottenness it is also advisable to surround its root neck by very rough sand or grit, this help a fast water drainage.

Propagation: By seeds, remembering that seedlings dislike strong light and dry conditions and need to be repotted frequently. 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.

Bibliography

Major reference and further lectures

  1. Hadley Nation “Super Kabuto and Rare Astrophytum: Limited Edition Collector’s Guide” Little Quin Publishing, 2007

  2. http://www.astrobase.de/Asterias/Artikel/esuperkap.html

  3. Sato, T., “J.C.P Color Hand Book Series No. 2, Volume 1, Hand Book Asterias Family” page 1-65, Japan Cactus Planning Co. Press. 03/25/1973

  4. Benadom, D., “Cacti & Succulents for the Amateur” in: Cact. Succ. Journ. (US), volume: 70 No. (6), page 314-315, 1998

  5. Kleszewski, K. P., “Verein der Kakteenfreunde Mainz/Wiesb. u. Umgebung, OG, Astrophytum asterias (ZUCC.) LEM. Am Standort in Mexiko…und in Kultur” in: Kaktusblüte, volume: No., page 25-28, 1998

  6. Kibayashi, A., “Cacti and succulents in Japan, part 1” in: Cact. Succ. Journ. (US), volume: 65 No. (3), page 126-127, 1993

  7. Kobayashi, A., “Cacti and succulents in Japan, part 3” in: Cact. Succ. Journ. (US), volume: 68 No. (5), page 245-249, 1996

  8. Sato, T., “Astrophytum asterias varieties” In : A Quarterly Cactus & Succulent Journal of Japan, volume: 1 No. (1), page 22-34, 1978

  9. Sato, T., “Astrophytum asterias” in: Cactus & Succulent Journal of Japan, volume: 9 No. 7, page 10-14, 1995

10 ) Sato, T., “Astrophytum asterias” in: Cactus & Succulent Journal of Japan, No. 3, page 10-14, Japan Cactus Planning Co. Press, 1995

  1. Sato, T., “Contest of Cactus & Succulent plant in Kyoto 1998” in: Cactus & Succulent Journal of Japan, No. 11, page 2-7, Japan Cactus Planning Co. Press, 1998

  2. Sato, T., “Contest of Cactus & Succulent plant in Saitama 1998” in: Cactus & Succulent Journal of Japan, No. 12, page 2-4, Japan Cactus Planning Co. Press, 1998

  3. Sato, T., Cactus & Succulent Journal of Japan, No. 6, page 2, 7, Japan Cactus Planning Co. Press, (unknown) 1999

  4. Sato, T., Cactus & Succulent Journal of Japan, No. 7, page 9, 10, 15, Japan Cactus Planning Co. Press, (unknown) 1999

  5. Sato, T., 1999 “The report of the grand meeting to celbrate the 20th anniversary of ‘KYOSENKAI’” in Cactus & Succulent Journal of Japan, No. 9, page 2-11, Japan Cactus Planning Co. Press,

  6. Anderson, M., “Grafting succulents” in: Cact. Succ. Journ. (US), volume: 69 No. (1), page 17-25, 1997

Gallery

Astrophytum asterias cv. Rensei
Astrophytum asterias cv. Rensei© Valentino Vallicelli · source · CC-BY-SA
Astrophytum asterias cv. Rensei
Astrophytum asterias cv. Rensei© Valentino Vallicelli · source · CC-BY-SA