Indoor plants
Calathea
Calathea
The genus name comes from the ancient Greek "kalathos" - basket: the leaves of some Calathea species were used for weaving baskets.
Calatheas are grown for their attractive patterned leaves, whose designs are exceptionally diverse. But there are exceptions: the ornamental-flowering Calathea crocata and Calathea warscewiczii.
This perennial herbaceous plant is decorative because of its leaves, which grow on upright petioles with leaf blades turned into a horizontal plane and always oriented toward the sun. Calathea has no stem. The blades of the elliptically elongated leaves usually have a striped coloration in various shades of green, sometimes with pinkish veins. The underside, however, is colored purple. Only one Calathea species — Calathea crocata — has uniformly colored leaves.
Calathea crocata (Calathea crocata) — a compact, attractively flowering but very demanding plant. It can be grown only under greenhouse or terrarium conditions, as it quickly drops its leaves in dry air. The leaves are rather unremarkable; it is valued for its striking orange-red bracts surrounding the inflorescences on erect flower stalks.
Calathea picta (Calathea picta) — with oblong leaves up to 20 cm long. On the upper side of the leaf there is a dark center with symmetrical stripes, a light band along the margin and a light central vein.
Calathea makoyana (Calathea makoyana) without doubt looks the most spectacular. It has paper-thin oval leaves up to 30 cm long on straight long petioles. From above the leaves are silvery with dark green edges, dark-green spots of varying sizes and a venation pattern. The underside of the leaves is dark purple. The petioles are pubescent, lilac-colored. Each rosette bears one photosynthetic leaf, surrounded at the base by several small scale-like leaves.
Calathea lancifolia or "remarkable" (lance-leaved) (Calathea lancifolia = C. insignis) also has a single leaf in each rosette. Its leaves are opaque, lance-shaped with wavy margins. On a light green background there are regularly alternating small and large ovals. The underside of the leaf is purple, the petiole green. A very graceful and at the moment rather rare plant in cultivation.
Calathea warscewiczii (Calathea warscewiczii) has large dark green velvety leaves with a light green pattern along the central vein. The underside of the leaves is dark purple. Before flowering it produces long jointed shoots that require support, so the plant needs plenty of space. The bracts are cream-colored; it blooms decoratively with white, cream or pink flowers. It is rather fussy and demanding of humidity. Misting is not allowed, as salt marks remain on the leaves that cannot be removed.
Calathea zebrina or zebra-like (Calathea zebrina) — a plant 40-60 cm tall with lance-shaped leaves up to 45 cm long and 16 cm wide. The leaves of Calathea zebrina are bright green with dark wide stripes along the lateral veins. The leaf surface is velvety, the underside purple. Flowers are gathered in dense, almost round or ovoid, spike-like inflorescences, white or lilac, on a short stalk.
Temperature: Calatheas are warmth-loving plants; in winter they are kept at no less than 18-20°C, and do not tolerate drafts or sharp temperature fluctuations.
Lighting: Good light, light shade, protected from direct sunlight. With insufficient light the leaf coloration is lost and becomes uniformly green, and the patterns merge into the overall leaf background. Conversely, under intense sun leaves turn brownish-red and burns appear. Calathea is often considered a shade-loving plant, however with insufficient light the plant will not become dense and large. They most often suffer from lack of light in winter.
Fertilizer: From April to August feed with a liquid complete fertilizer for indoor decorative-leaved plants every two weeks; Calathea crocata is fed with fertilizer for flowering houseplants. Calatheas are sensitive to excess or overfeeding with fertilizers.
Air humidity: Likes humid air up to 90%. Regular misting of the leaves is necessary. The pot is placed in moist peat or an aquarium. Leaves are periodically wiped with a sponge — especially those Calathea species that have stiff glossy leaves; varieties with thin, velvety leaves are better not wiped, but they need humid air no less.
Repotting: Annually in spring into a loose, light soil consisting of 2-3 parts leaf mold, 1 part peat, 1 part humus soil, 1 part coniferous soil with some sand. Pieces of charcoal are added to the soil mix. Calathea does not tolerate lime in the soil. The container for these plants should not be deep. For successful indoor cultivation, rhizomes are covered with damp sphagnum moss. If you cannot prepare the potting mix yourself, you can use a commercial soil for Marantaceae, azalea soil will also do.
Propagation: By dividing the rhizome when repotting in spring. Propagation by seed is also possible.