Costus

Family. Zingiberaceae.

Origin. India, Brazil.

Description. Costus is a relatively large genus containing about 100 tropical perennial herbaceous plants with large leaves, up to 20 cm long, arranged around the stem. Costus shoots have smooth, reddish bark. The leaves are oblong-lanceolate, green, may have velvety pubescence, and when damaged they emit a ginger smell. Variegated varieties have white or red longitudinal stripes along the entire length of the leaf blade. During the flowering period, large cone-shaped inflorescences resembling cones appear at the tops of the stems. The bright, showy flowers bloom in turns and remain open for a short time, have ruffled petals and resemble irises in appearance. Flower shades include white, pink, crimson, orange, and some plants produce flowers with petals in 2 or even 3 different shades.

Height. Depending on the species, the height in the natural environment can vary from 30 cm to 3 m. Indoor plants usually do not exceed 60 cm.

Care at home

Flower growing temperature

Keep the costus at a temperature of 20 - 22 ° C for almost the entire year. However, after flowering, the plant goes into a dormant state and for several weeks the temperature should be lowered to 16 - 18 ° C. The minimum permissible temperature at this time is about 13 ° C. 

Propagation 

The rhizomes of large adult specimens are divided in spring and summer. It is also propagated by leaf and apical stem cuttings, however, this can be done mainly by specialists who can create suitable conditions for growth.

Lighting

Costus prefer a well-lit place with access to direct sunlight in the morning. With adequate humidity they can be grown all day in direct sunlight.

How to care

This species is much more resilient than most of its tropical counterparts, but is also very demanding of growing conditions. Suitable only for experienced gardeners. The bushes will appreciate a summer stay on the balcony or veranda. Long stems can be cut in late spring to maintain a compact shape, old and weak shoots are removed to prevent the development of diseases and maintain a neat appearance.

Substrate

Based on peat, leaf humus and turf soil. To improve drainage, add coarse sand and perlite beads.

Feeding

During the growth period, costus needs weekly fertilizing with complex fertilizers. During the dormant period, do not feed. 

Purpose

A real jewel that requires a worthy frame in the form of competent care. Valued as an ornamental foliage and as a flowering plant. It is advisable to grow costus in an indoor greenhouse.

Flowering time

Summer.

Air humidity

Requires very high humidity. Be sure to spray the foliage or place it on a mesh tray and pour water on the bottom. You can also use a room humidifier to increase humidity or surround the pot with a layer of damp sphagnum moss. Does not like drafts.

Soil moisture

Watering should be abundant and regular. The soil should be evenly moist, but not waterlogged. In spring and summer, the pot can be immersed in a large container of water for a few minutes. In autumn, reduce the frequency of watering slightly and allow the top layer of soil to dry out between waterings.

Transfer

Costus grow quickly and, as a rule, require an annual spring transplant, which is carried out when growth begins. 

Pests and diseases

The edges of the leaves dry out and turn brown when kept in a dry atmosphere.

Pests can include mealybugs, aphids, and scale insects.  Red spider mites when kept too dry. 

Note

It can live indoors for many years, but only if its needs are carefully considered.

Varieties:

Costus igneus

An evergreen perennial herbaceous plant with thick, weakly branched shoots up to 60 cm high and large, lanceolate, glossy, green leaves. The leaves are arranged spirally around the stems. The lower surface of the leaf blades is often colored purple. The flowers are bright, orange, solitary, up to 4 cm in diameter, appearing in the warm season on the tops of the stems.

The dried leaves of the plant are used in folk medicine as an antidiabetic, anticancer and diuretic.

Costus erythrophyllus

A spectacular decorative foliage perennial up to 60 - 100 cm high with erect, strong shoots. The leaves are broadly lanceolate, entire, bluish-green. The lower surface of the leaf blades has a reddish-burgundy tint. The flowers are soft pink, appearing at the tops of the stems in small inflorescences. 

Costus speciosus

Herbaceous perennials with thick, branched shoots at the base, often taking on an elegant spiral shape. The leaves are narrow, lanceolate, slightly bent along the central vein, glossy, arranged spirally. During the flowering period, large cylindrical inflorescences with red or burgundy bracts and white, showy flowers up to 10 cm in diameter appear at the tops of the shoots.