Culture
Best grown in evenly moist, well-draining soil in part shade. Some cultivars tolerate more full sun. Hardy in Zones 10-11. Pinch back stems to encourage a more bushy habit. The blooms are typically not showy and can be removed so as not to detract from the foliage. Seed cultivars can be started indoors from seed 8-12 weeks before last frost date. Inexpensive starter plants (in small pots or flats) can be purchased from most nurseries in spring for beds and containers. Containers may be brought inside in fall before frost for overwintering. Similarly, favorite plants may be dug and potted in fall for overwintering as houseplants. Cuttings from favorite plants (easily rooted in a glass of water or in clean potting soil) can also be taken in fall for overwintering.
Noteworthy Characteristics
Plectranthus is a genus of about 350 species of annuals, evergreen perennials, semi-succulents and shrubs from Africa, Madagascar, Asia, Australasia and Pacific Islands. Commonly called coleus, hybrid cultivars are widely grown as ornamentals. An almost infinite number of leaf color combinations are available including most colors of the spectrum except true blue. Cultivars range in size from dwarf 6” tall plants to large mounded 3' tall plants. Four-sided stems are semi-succulent. Showy multi-colored leaves are generally ovate to oblong and toothed. Leaves frequently feature mixtures of colors in irregular patterns. Blue to white nettle-like flowers (more common on seed strains) bloom in racemes in summer to early fall, but are not showy and tend to visually detract from the symmetry and attractiveness of the plants.
Genus name comes from the Greek words plectron meaning "spur" and anthos meaning "flower" in reference to the spur-shaped flowers of some members of the genus.
'Balcenna' features chartreuse foliage with contrasting copper-pink splotches and burgundy undersides. The leaf margins are deeply serrated and slightly ruffled, revealing the dark undersides. Mature plants will reach up to 2.25' tall and 1.75' wide. The terminal spikes of small, pale lavender flowers are not showy and may not be produced. Commonly sold at nurseries and garden centers under the name HENNA. Plant patent number PP19149 applies to this cultivar.
Problems
No serious insect or disease problems. Watch for mealybugs and mites.
Uses
Borders where winter hardy. Containers or hanging baskets for decks or patios. Bedding plant for annual color. Houseplant.