Argyroderma AUREUM

Argyroderma AUREUM - Golden argyroderma, Argyroderma aureum.

"Living Stones" seed series.

Argyroderma is a genus of supersucculents with silvery-green smooth leaves in the ice plant family (Aizoaceae). From the Greek words argyro (silver) and derma (skin) - silver-skinned. Dwarf succulents 3-5 cm (1.2-2.0 in) tall, with rosettes of 2-4 very fleshy leaves, usually growing in clumps, but some species (A. pearsonii, A. ringens, A. testiculare) - always solitary. They are found in the Cape Province of South Africa, south of the Orange River and further south in the Karoo Desert, in the Vanrhynsdorp district, on rocky and sandy soils, occasionally burying themselves in the sand during hot dry months.

The plants are very variable in nature; even in individual populations of a single species flower coloration can vary. Previously, more than 50 species were counted in the genus, but according to modern data the genus contains only 11 species and 1 subspecies, without varieties. From other "living stones" argyrodermas differ in completely plain leaves, without any markings. In nature, in the habitats of argyrodermas, precipitation falls mainly in winter (from May to September) and averages 50-70 mm (2.0-2.8 in) per year. In summer it is dry and very hot - up to 40 °C (104 °F). Winters are cool, especially at night, but during the day the air warms up substantially, and if frosts occur, they are short-lived, and the temperature drops only slightly below 0 °C (32 °F).

Golden argyroderma is a miniature supersucculent resembling an egg in shape, up to 3 cm (1.2 in) tall. It consists of a pair of fleshy leaves. The leaves are silvery-blue in color, separated by a transverse fissure and fused at the base. Each season the leaves are renewed. It blooms in autumn. The flowers are large, up to 5 cm (2.0 in) in diameter.

Usually argyrodermas germinate without difficulty, but sometimes sowings still fail. It is better not to sow all available seeds at once, but to divide them at least into two batches - sow one portion and after about 15 days assess germination energy. If the seeds showed good germination, sow the second portion using the same technique. If seedlings did not appear, the second portion can be kept dry for 25-30 days in a refrigerator at +5 °C (41 °F), and before sowing soaked for 5-6 hours in a weak (light-pink) solution of potassium permanganate KMnO4. Sometimes soaking in potassium permanganate alone is sufficient. Soaking seeds for 4-5 hours in gibberellic acid GA3 - 1 g per 1 L of distilled water significantly increases the germination percentage. Treatment with gibberellin "forces" light-sensitive argyroderma seeds to germinate even in the dark.

Many specialists advise sowing argyrodermas before winter, in October-November, but in this case lighting issues for the sowings will have to be addressed. It is much simpler to sow seeds in late February to early March - in this case supplementary lighting is not required, and young seedlings will have time to strengthen sufficiently before winter. In the first months of life it is desirable not to transplant seedlings, so to a substrate consisting, for example, of sand and perlite, about 30% leaf soil should be added. The substrate must be steamed, and sprinkled on top with a layer of baked fine quartz sand.

Seeds are not buried in the soil, but spaced at a distance of about 0.5 cm (0.2 in) so that future seedlings do not crowd each other. Seeds can be sown in rows (which is much simpler) and lightly dusted with sand. Watering from above is undesirable, as fine seeds can be washed away by water; it is better to lower the bottom of the dish into water and hold until the substrate is moistened. The sowing is covered with glass or cellophane and kept at a temperature not above 25 °C (77 °F). Optimal germination temperature: 15-17 °C (59-63 °F) at night and 20-22 °C (68-72 °F) during the day. Under optimal conditions, the first seedlings appear on days 7-8, and total germination continues for 30-40 days.

The cover from the sowing dish does not need to be removed for up to six months, but when temperatures rise in summer, seedlings should be ventilated after 2-3 weeks already. Even better, from the moment sprouts emerge, remove the cover glass daily for 1-2 minutes for airing, and after a month ventilate for 5-10 minutes several times a day. Air circulation is very important for seedlings, so after 2 months it is best to remove the cover completely.

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Excellent plants for indoor culture - they take up little space, are unpretentious in care, and winter under apartment conditions without issues. It requires a loose mineral substrate, good drainage. It does not tolerate overwatering. In summer, the plant should receive plenty of direct sunlight and limited watering. In winter, it is kept dry at a temperature of 12-15 °C (54-59 °F).

Seedlings require sufficient light, but during the first months they must be shaded from direct sunlight. It is best to water from below, as with sowings, ensuring that the soil remains only moist, not wet. They are watered occasionally, but more abundantly than adult plants - over-drying is harmful to seedlings. Daily misting is very beneficial. It is best to repot young argyrodermas after a year, unless, of course, the substrate becomes covered with algae and mold. When grown in a small group, the plants feel better than alone. They also get along wonderfully together with lithops, conophytums, and aloinopsis. Roots in argyrodermas (unlike, for example, lithops) are thread-like, so shallower containers suit them. After repotting, plants should not be watered for a week so that root wounds have time to heal.

The soil required is slightly acidic, consisting, for example, of leaf soil and sand (2:3) or a mixture of leaf soil, turf soil, and coarse sand (1:0.5:1). Adult plants are repotted once every 2-3 years. Argyrodermas are watered very carefully, beginning in April and until late autumn. Excess moisture leads to unsightly cracking on the leaves that can destroy the "living stones". During flowering, plants can be fed with a weak solution of cactus fertilizer. In summer they feel comfortable in light partial shade at temperatures above 30 °C (86 °F). In winter and early spring, argyrodermas are kept dry at a minimum temperature of 8 °C (46 °F) (preferably 12-15 °C (54-59 °F)). At this time light is not essential for them, and plants can overwinter somewhere in a dark spot on a wardrobe or on a shelf far from a window.

With proper care, argyrodermas in collections live for a very long time and bloom regularly. Seedlings usually begin blooming after 3-4 years, but cases are known where plants opened their first flowers in the second year after sowing. Solitary buds appear between the leaves on a short pedicel. Yellow, pink, purple-red, or more rarely white, flowers with a diameter from 1.25 to 3.2 cm (0.5 to 1.3 in) open in the middle of the day or closer to evening, and close at night. Flowers last up to 10 days. Unpollinated ones - even longer. In their homeland, argyrodermas bloom in autumn and early winter (from April to June). In the Northern Hemisphere, the flowering period also falls in autumn and early winter (usually from October to December).

The flowers are bisexual; cross-pollination is required to obtain seeds. In nature, "living stones" are pollinated by various insects. In culture, accidental hybridization is not excluded, so if you are certain of the "purity" of your plants, during flowering they should be screened in some way from other species and pollinated "manually".