Zantedeschia AETHIOPICA

Zantedeschia AETHIOPICA - Calla lily, Arum lily, Common arum lily, Richardia, Calla Lily.

Zantedeschia is a genus in the family Araceae comprising 8 recognized species distributed in central and southern Africa. Representatives of the genus are found in marshy and riparian habitats, wet meadows, along the banks of streams and water bodies, as well as in areas with pronounced seasonal moisture.

The genus is characterized by perennial herbaceous plants with stout underground rhizomes or thickened underground organs, forming dense clumps. The leaves are basal, on long fleshy petioles, most often sagittate or hastate, smooth, thick, and in some species spotted. The inflorescence is typical of aroids and consists of a spadix surrounded by a large spathe.

The flowers in Zantedeschia are small and located on the spadix, while the ornamental effect is created specifically by the spathe, which in various species can be white, cream, yellow, pink, or purple. After flowering, fleshy berries form, inside of which rounded or slightly angular seeds develop. Some species exhibit a pronounced alternation of active growth and a dormant period.

Calla lily is a rhizomatous perennial that forms large dense clumps usually 60-100 cm (24-39 in) tall, sometimes taller in shaded and very humid locations. In the wild, the species is distributed across South Africa, Eswatini, and Lesotho, where it occurs along the shores of water bodies, in swampy depressions, wet meadows, and moist mountain habitats. The leaves are large, dark green, glossy, sagittate, on long thick petioles.

Main flowering usually occurs in spring and summer, although under favorable conditions individual flower stalks can appear at other times. The spathe is large, pure white, funnel-shaped, surrounding a yellow spadix. After pollination, the spathe gradually turns green, concealing the maturing berries, which later turn yellow and become soft.

In cultivation, this species is prized as an ornamental, container, and cut-flower plant. It is used to landscape moist garden areas, edges of decorative ponds, semi-shady flowerbeds, and winter gardens, as well as an eye-catching pot plant with large foliage and recognizable white inflorescences.

Seeds form inside fleshy berries maturing beneath the greened spathe, and after cleaning usually have a grayish or gray-brown coloration, a dense coat, and a rounded or slightly angular shape. Fruit pulp is completely removed before sowing. Scarification and stratification are generally not required. Before sowing, brief soaking can be conducted first in warm water at 50-60 °C (122-140 °F) for several minutes, then in a 1% potassium permanganate solution for 1-2 hours. Growth stimulants can additionally be used, such as SUPERthrive, HB-101, Aminozol, Epin, or Zircon.

Sowing is carried out in spring. A clean, loose seedling substrate with addition of perlite or fine sand is used. Seeds are sown sparsely, since seedlings form fleshy roots early, and are covered with a light layer of soil. Moistening is performed from a spray bottle or with careful watering. The container is kept in a greenhouse or under film at a temperature of about 21 °C (70 °F), in bright diffused light, with regular ventilation. Waterlogging and complete desiccation of the sowings are impermissible.

First sprouts usually appear in 2-3 weeks. The most typical germination period is several weeks. The maximum germination period can reach 4-6 weeks. After sprouts appear, the cover is removed gradually, and seedlings are provided with stable moisture and good lighting without overheating. Pricking out is carried out once the plants become large enough for safe transplantation, taking into account that their young root system is fleshy and sensitive to damage.

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For most Zantedeschia species, bright lighting with protection from scorching midday sun is used, especially in indoor culture and in hot regions. Placement on eastern, western, or southeastern windows is considered best, and in the garden - in spots with morning sun or light partial shade. With insufficient light, flowering weakens, petioles stretch, and leaves become less dense.

During the active season, a temperature of about 18-25 °C (64-77 °F) is maintained. In winter for indoor plants, maintenance within 10-16 °C (50-61 °F) is desirable if the species enters relative dormancy, although with stable moisture and mild conditions Calla lily can retain foliage longer. Temperatures below 5 °C (41 °F) are undesirable because leaf and rhizome tissues are damaged by cold.

Watering during the growth period is abundant, as the plant prefers consistently slightly moist soil and tolerates complete drying out poorly. Soft or settled water is used. When growing in a pot, stagnant water without air access must not be permitted, although brief very wet conditions are tolerated better than overdrying. In dry air, leaves may lose turgor and dry out along the edges, so increased air humidity is tolerated well. The leaf surface is periodically cleaned of dust.

For planting, a nutritious, moisture-retentive yet breathable substrate is used with additions of perlite, leaf mold, humus, and a small amount of coarse sand. Drainage is necessarily placed on the bottom. Spacious pots are used, as rhizomes expand quickly. Repotting is carried out as the container fills, usually once every 1-2 years. During active growth, fertilizer solutions focused on flowering crops are applied once every 2 weeks. Spent flower stalks and old leaves are promptly removed.

In addition to rhizome division, which is used very often for the genus, Zantedeschia can also be propagated by seeds. When dividing, sections with renewal buds are slightly dried and then planted into moderately moist soil.