[Ebook Việt Hoá] The Instant Guide to Healthy Houseplants: Aporocactus (Rat’s tail cactus)

English

There are some half-dozen species of this genus of hanging cactus. The most common of these, Aprorocactus flagelliformis, has been grown on windowsills for many years. It produces flowers all along its stems in early spring and is popularly known as the rat’s tail cactus from the form of its limp, 

hanging stems. Of the other species, A. flagriformis and A. conzzatti are the most likely to be seen. There are also some very attractive flowering hybrids – crosses between Aprorocactus species and Epiphyllums (known as aporophyllums) – and other related large-flowered species that have flowers ranging from pure pink to deep reel. These make springy-stemmed, semi-pendant, freely flowering plants that are also very suitable for hanging baskets. 

Light 

Grows best when on a sunny windowsill indoors or when hung from the upper part of the window frame, so that its stems can hang in the light. If grown in a greenhouse, shade lightly in summer, as strong sun through glass may scorch the stems. 

Temperature 

Minimum during the winter, 40-50°F (4-10°C); maximum during the summer (when plant needs fresh air continually), 100°F (38°C).

Repotting 

Repot each spring into pot next size larger until in 6-in (15-cm) pot. After this, repot in same-sized container each year with fresh potting soil after shaking off as much of the old soil as possible. After repotting, leave dry for 2 weeks. 

Feeding 

Feed once a month in spring and summer with a low-nitrogen fertilizer (5-10-10). 

Soil 

Use soilless mix with no grit. 

Water 

Water weekly in spring and summer so that soil just dries out between waterings. Water just enough in winter to stop plant from drying out completely; once every 3-4 weeks is probably enough. Mist once a week in spring and summer and once every 6-8 weeks in winter. 

Cleaning and pest control 

Spray with water weekly in spring and summer to keep the dust off. In winter spray about once every 6-8 weeks. Use pesticides as needed and in accordance with label directions. 

Taking cuttings 

• 1. After flowering is finished, cut lengths of stem 2-3 inches (5-8 cm) long with sharp knife, cutting at an angle. 
• 2. Dust ends of both cutting and stem with hormone rooting powder containing fungicide. Leave cutting to dry for at least 2 days. 
• 3. Prepare a 2- or 3-in (5- or 8-cm) pot with potting soil and place cutting on surface. 
• 4. Cover just enough to hold it upright or rest tip against side of pot. Keep in light (not sunny) place for 2-3 weeks until roots develop. Then start watering. Repot when roots fill pot. 

What Goes Wrong 

• Soft brown or black patches at the of the plant or on stems above the soil: Rots of various kinds. Generally a result of cooler temperatures and overwatering. Cut back all infected areas to solid, healthy tissue with a sharp knife. Let dry for 2 or 3 days to heal cut surfaces; then repropagate. Grow in proper temperature; do not overwater or overfertilize. 
• Skin turns brown; fine webs between spines and ridges; tiny red-brown insects seen under a magnifying lens: Red spider mite. Spray with a contact insecticide or use either insecticidal soap or denatured alcohol on a cotton swab. Isolate infected plant from healthy plants until insect is controlled. Repeat applications every 10 to 14 days, or as indicated on the insecticide label, until insects are controlled. 
• Plant does not seem to grow when repotted; cottonlike tufts containing sausage-shaped bugs appear on roots.: Root mealy bug. Remove from pot, wash off soil and swirl roots in a solution of pyrethrum or insecticidal soap. Allow roots to dry for several days before repotting in a clean pot with fresh potting soil. 
• Brown marks on side of plant facing the light; marks larger than shown above: Scorch of tender growth exposed to bright sunshine. Such injury is common in the spring. Accustom plants to stronger light by moving them into strongly lighted areas gradually. Damage is irreparable, but plant itself will usually recover if growing point has not been injured.
• Brown spots and blotches appear on skin, especially after the winter: Cold marks made by keeping the plant in too Iowa temperature during the winter. Do not place on windowsill between curtains and glass on frosty nights. Maintain temperature at 50- 55°F (10-13°C). 
• New growth elongated, narrower than old growth; fewer flowers: Lack of light. Place in better light. For first 2 or 3 weeks, shade with white paper or curtain to accustom plant to stronger light. 
• White woolly tufts appear: Mealy bug. Dislodge using cotton swab dipped in 35-percent denatured alcohol. Or spray with insecticidal soap or malathion preparation applied according to manufacturer’s instructions. If the infestation is severe, use E a pyrethrum-rotenone spray near an open window or outdoors. 
• Skin wrinkles, shrinks and looks  dull: If during dry period in winter, natural contraction. If in growing season, plant is too dry or (if watering correctly) root loss. If dried out, water (in winter, watering too much or too often will kill plant). Shade during hottest times of day or year. If roots have rotted, water less often.