Stapelia LEENDERTZIAE

Stapelia LEENDERTZIAE - Leendertz's stapelia, Stapelia leendertziae.

Stapelia is a genus of succulent plants in the dogbane family (Apocynaceae), belonging to the stapeliad succulent group and including several dozen species distributed primarily in Southern Africa and adjacent arid regions. Members of the genus are found in dry shrubland communities, savannas, stony places, and among grasses and low vegetation, where they receive bright light, good ventilation, and rapid soil drying.

The plants develop as low-growing perennial succulents with fleshy branching shoots. The stems are usually four-angled or multi-angled, green, grayish-green, brownish-green, or slightly reddening in the sun, with toothed ribs and reduced leaves in the form of minute scales. The root system is comparatively shallow, which makes stapelias particularly sensitive to heavy, wet soil.

The flowers of stapelias are large or medium-sized, star-shaped, fleshy, often with spots, stripes, wrinkles, hairs, and an intricate velvety surface. In many species, the flowers possess a specific scent that attracts pollinating flies. After pollination, paired follicles form with numerous flat seeds equipped with a silky plume for wind dispersal.

Stapelia leendertziae is a succulent. The stems are pale green or reddish, 4-ribbed, and succulent. The flowers are deeply cup- or bell-shaped or more open star-shaped, about 8 cm (3.1 in) in diameter and 7-8 cm (2.8-3.1 in) long. They are purplish-brown or dark maroon, folded inside the cup, densely velvety, and malodorous.

Stapelia seeds are flat, brown or dark brown, equipped with a long silky plume that is carefully removed before sowing.

Before sowing, seeds can be soaked for 2-4 hours in a weak solution of potassium permanganate or biofungicide with the addition of a growth stimulant: SUPERthrive, HB-101, Aminosol, Epin, or Zircon. A sterile mineral sowing substrate based on cactus soil, fine perlite, and washed sand is used. Seeds are spread over the surface, lightly pressed, and sprinkled with a thin layer of sand or sifted substrate about 1-2 mm (0.04-0.08 in).

The sowing is gently moistened with a spray bottle, covered with a transparent lid, or placed in a mini-greenhouse. Temperature is maintained at 22-26 °C (72-79 °F); bright diffused light without direct overheating is required. Aeration is carried out daily for 10-15 minutes, condensation is wiped away, and the substrate surface is kept slightly moist but not wet.

The first seedlings may appear within 7-14 days; germination usually takes 2-4 weeks, and under cool conditions can extend to 6-8 weeks. After emergence, the cover is gradually opened; seedlings are kept under bright diffused light, moderate warmth, and cautious watering. Pricking out is performed after the seedlings strengthen and small fleshy shoots begin to grow, when the plants can be easily moved with a small clod of substrate.

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Bright diffused lighting with soft morning or evening sun is used for stapelia. East, southeast, and well-lit west windows are best suited, while on a southern window in summer protection from overheating and direct midday rays is required. In case of light deficit, shoots stretch out, become thin, and set buds poorly, and during sudden overheating they may suffer burns.

During active growth, temperatures of 20-28 °C (68-82 °F) are maintained; with good ventilation, the plant tolerates summer heat. Overwintering is preferably bright and cool, at 10-15 °C (50-59 °F), with very infrequent watering. The minimum safe temperature for a container plant is about 10 °C (50 °F) when kept dry. Cold damp soil quickly causes rot of roots and the base of shoots.

Watering is carried out cautiously, after the soil dries out completely. During the warm season, the plant is watered moderately, but without permanent dampness, and excess water from the drip tray must be drained after 15-20 minutes. During the cool dormant period, watering is sharply reduced and done only upon noticeable wrinkling of the shoots. Water must not linger at the base of the stems, and misting is generally not required.

The soil used is very loose, mineral, and quick-drying: a ready-made cactus and succulent mix, coarse sand, fine gravel, pumice, zeolite, crushed brick, perlite, and a small amount of leaf mold. A drainage layer must be placed at the bottom. Pots are chosen shallow, wide, stable, and with drainage holes, as stapelia roots are generally shallow and especially sensitive to waterlogging.

Repotting is carried out in spring, usually once every 2-3 years or after significant expansion of the clump. Careful potting on is used, removing old, damaged, or rotted shoots. After repotting, the plant is kept for 5-7 days without watering. Fertilizer is applied only during active growth, once every 4-6 weeks with a weak solution of cactus and succulent fertilizer low in nitrogen. Excess nitrogen is undesirable because it causes soft watery growth and increases the risk of rot.

Propagation in cultivation is most often done by stem cuttings. Cuttings are taken from mature shoots, dried in the shade for at least several days, and with large cut surfaces - up to 1-2 weeks, until the cut is completely dry. Then the cuttings are planted in a dry or barely moist mineral substrate, and initial waterings are done very cautiously, only after rooting begins.