Othonna PROTECTA

Othonna PROTECTA - Protected othonna, Crassothonna protecta.

Othonna is a genus in the Asteraceae family, comprising about 85 recognized species distributed mainly in southern Africa, from Angola and Namibia to the Cape Provinces, Lesotho, Eswatini, KwaZulu-Natal, Free State, Northern Provinces, and Zimbabwe. Representatives of the genus are found in dry shrubland communities, on sandy and rocky slopes, in rock crevices, on plains, and in seasonally arid subtropical habitats.

The genus is characterized by tuberous or thickened underground organs, sometimes a pronounced caudex, as well as succulent or semi-succulent shoots. Growth forms vary from small tuberous herbs to subshrubs and dwarf shrubs. Leaves in different species can be entire, lobed, or dissected, sessile or petiolate, often fleshy, adapted to seasonal moisture deficiency.

Inflorescences in Othonna are flower heads (capitula), most often yellow, solitary or gathered in small groups. The fruits are single-seeded achenes, usually very light, equipped with a pappus of bristles that aids wind dispersal. Many species are characterized by seasonal growth, in which leaves develop during the cooler and wetter period of the year.

Othonna protecta is a relatively cold-hardy species, growing up to 30 cm (12 in) in height and up to 5 cm (2 in) in caudex diameter. Alternate succulent cylindrical green leaves up to 3 cm (1.2 in) long and about 3 mm (0.12 in) in diameter can turn reddish-purple in the hot and dry season when growth slows down. The leaves have longitudinal grooves. Flowers are yellow, sometimes with a greenish tint.

The seeds are small, enclosed in light single-seeded fruits equipped with a white pappus of bristles. Before sowing, the achenes are cleaned of inflorescence remnants. Scarification and stratification are usually not required. To prevent fungal infections, a brief soaking can be carried out first in warm water at 50-60 °C (122-140 °F) for a few minutes, then in a 1% potassium permanganate solution for 1-2 hours. Additionally, the use of stimulants is permitted, such as SUPERthrive, HB-101, Aminosol, Epin, or Zircon.

Sowing is preferably done in autumn, corresponding to the natural cycle of the species, although under controlled conditions it is possible at other times of the year. An air- and water-permeable substrate based on coarse sand, fine perlite, and a small organic fraction is used. Seeds are spread on the surface or covered with a very thin layer of sifted sand. Moistening is done from a spray bottle. The container is kept in a mini-greenhouse or under film at a temperature of about 15-22 °C (59-72 °F), in bright diffuse light, with daily airing. Waterlogging and complete drying out of the sowings are impermissible.

The first sprouts usually appear in about 10-14 days. The most typical germination period is 2-3 weeks. The maximum germination period can reach 4-6 weeks. After sprouts emerge, the covering is removed gradually, lighting is increased, and watering is shifted to a very careful regime. Pricking out is carried out after several true leaves have developed, when the seedlings are strong enough to endure transplantation without damaging the young tuberous base.

© Greeniverse. All rights reserved.

For most cultivated Othonna species, the brightest possible lighting is used. The best placement is south, southeast, or southwest-facing windows, providing several hours of direct sun. In insufficient light, shoots stretch, internodes elongate, and flowering diminishes. Supplemental lighting can be used during overcast seasons.

During the active growth period, which in tuberous South African species usually occurs in autumn, winter, and spring, a cool-temperate regime of around 12-22 °C (54-72 °F) is maintained. Summer dormancy is best spent at 20-28 °C (68-82 °F) in dry and well-ventilated conditions. A brief drop in temperature is possible only when kept nearly dry, while prolonged chilling below 5 °C (41 °F) is undesirable, especially in wet substrate.

Watering is carried out moderately during the active growth period, after the top layer of soil dries out. Soft or settled water is used, avoiding waterlogging of the root zone. Excess water from the drip tray must be drained. In summer, when the plant enters semi-dormancy, watering is sharply reduced and an almost dry regime is maintained. Overwatering quickly leads to rotting of the tuber and the base of the shoots, while prolonged complete drying out during the active season halts growth and bud formation. Misting is usually not required, but dust is gently cleaned from the leaves.

A very loose mineral-organic substrate with a high content of perlite, coarse sand, and fine drainage is used for planting. Shallow pots with drainage holes are suitable. Repotting is carried out as the volume is filled, usually once every 2-3 years, before active growth begins. The plant is fed infrequently, once every 3-4 weeks during the growing season, with a weak solution of succulent fertilizer. Heavy pruning is usually not required; only dry or weakened shoots are removed.

Stem cuttings are not always possible for the genus and have limited application in tuberous forms, so seed sowing often remains the primary method for renewing collections. In species with elongated stems, rooting is possible only in very light mineral soil and under strict moisture control.