DESCRIPTION: These delicate plants have colored leaves or beautiful flowers. These plants are natives of Indonesia and Africa. Coleus plants that have ornamental leaves are descended from C. Blumei, which has nettle-like, bronze-colored leaves. The colors of their foliage range through yellow, red, crimson, and pink. The flowers that are produced on the varieties grown for their colorful leaves are hardly noticeable. Others have plain green leaves but bear gorgeous spikes of blue flowers in the winter. They are not good as houseplants, but will survive in a greenhouse having a minimum night temperature of 55-60 degrees with a 5-10 degrees rise in the daytime and a fairly humid atmosphere. Coleus fredericii is an annual or biennial plant that has deep purple flowers in late winter or early spring. It grows 3-4 feet tall. C. amboinicus is a shrubby plant that grows about 2 feet tall. It has thick, brittle, fuzzy green leaves that have a strong aroma. Their flowers are lavender-pink.
POTTING: When grown indoors, these plants need rich, well-drained soil that contains a good amount of leaf mold or peat moss. When grown outside they will flourish in any good soil in full sunshine. For the plants that are grown for their flowers, light shade should be provided. To keep them in good shape and help them grow bushier, the tips of the shoots should occasionally be pinched. Make sure to do this with an upward pull (especially with C. thyrsoideus) however, because if pinched down, a long strip of skin will be stripped from the stem along with the leaf. When the plants have filled their pots with roots, they should receive weekly doses of dilute liquid fertilizer. Their soil should be kept moist.
PROPAGATION: Coleus can be easily raised from seed. Seeds are sown in early spring in pots containing light, sandy soil. They are covered lightly with soil and glass is placed over it. Keep them in 65-75 degree temperatures. The seedlings are then set 1 inch apart in flats of well-watered soil and shaded until established. They are then potted separately. Cuttings of shoots, 2 inches long, are inserted into sand, vermiculite, or other rooting mediums at any time of year. They should be kept in a warm, moist propagating case or be covered with a bell jar until they have formed roots. After they have rooted, they are treated as seedlings. When they have almost filled up their pots with roots, they should be transplanted into larger pots that are filled with the same kind of soil mixture as described above in the potting section, but with the addition of a little bone meal and dried cow manure. The last repotting should be into pots ranging from 6-9 inches.
VARIETIES
Colored leaves
C. Blumei and its varieties.
Beautiful flowers
C. thyrsoideus;
C. shirensis;
C. Fredericii;
C. amboinicus.