Close relatives of coleus; native to many tropical regions of the world. They have square stems, opposite pairs of fleshy, tooth-edged or scalloped leaves, and whorls of tubular, two-lipped blossoms. Some are highly aromatic, used as seasonings or home remedies. Others are grown for their attractive foliage, yet others for their striking floral displays. Some are good bedding plants for summer color; some make dense, weed-suppressing ground covers for frost-protected areas. Several are trailing plants that drape gracefully from hanging baskets or wall pots. All are superb in containers, either alone or in combination with other plants.
P. argentatus and P. fruticosus are the shrubbiest of the species listed here, but the others get somewhat woody at the base after a year or more. Pinch all types to induce branching; discard old plants when they become leggy or too woody, and start new ones.
P. amboinicus (Coleus amboinicus). CUBAN OREGANO, SPANISH THYME, INDIAN MINT. From Africa. Summer-blooming trailer to 1 ft. high, 3 ft. wide, with white, lilac-pink, or light purple flowers in 6-in. spikes. Velvety, ovate, gray-green leaves are 3 in. long, with broadly toothed edges. Popular in Cuban cooking, with a fragrance that falls midway between oregano and thyme but has a sweet note not present in either. Leaves of 'Variegatus' are bordered in cream, with the very edge often tinged bright pink; excellent flavor. 'Well-Sweep Wedgwood', with extra-sweet flavor, has Wedgwood blue flowers and leaves in chartreuse and gray-green with a dark green margin.
P. argentatus. SILVER SPURFLOWER. From Australia. Erect to spreading plant to 3 ft. tall, 6 ft. or wider. Densely hairy, scallop-edged, oval leaves to 7 in. long are silvery gray-green, with a light purplish flush on growing tips and stems. Pink-tinged white flowers in foot-long spikes in late summer, fall. Best in at least half-day direct sun; will take hot afternoon sun if adequately watered. 'Silver Shield' is more compact to 2430 in. tall, has bluish white flowers, and leaves with a silvery sheen.
P. ciliatus. From southern Africa. Handsome, burgundy-stemmed trailer to 612 in. high, 35 ft. wide. Excellent dense ground cover. Blooms in late summer and fall, with white or purplish flowers in 8- to 12-in. spikes. Oval leaves to 3 in. long, with finely toothed edges and pointed tips; leaves have deep green upper surfaces, burgundy undersides and veins. 'Old Gold' leaves are yellow or chartreuse above, burgundy beneath; new leaves are flushed with burgundy. 'Tricolor' is similar, but tops of leaves also have dark green splotches. Both selections have white blooms. 'Lemon Twist' has leaves edged yellow with lemony fragrance.
P. cylindraceus. VICK'S PLANT, MENTHOLATO. Zones CS, TS; USDA 9-11. From Africa. Mounding growth to 13 ft. high, 24 ft. wide. Sometimes blooms, bearing blue or lavender flowers in dense, narrow, pointed spikes 1215 in. long (there may be a pair of shorter spikes near base). Velvety, triangular, gray-green leaves 112 3 in. long, with three to five broad teeth on each side of leaf. Foliage smells like a combination of camphor and menthol and is used medicinally in Mexico.
P. ecklonii. Zones LS, CS, TS; USDA 8-11. From south Africa. Tender, multistemmed shrub growing 46 ft. tall. Very showy blue-purple flower spikes, 612 in. tall, top plant in fall. Pink- and white-flowering forms exist. Cut back to 10 in. in winter.
P. forsteri. From Australia, Fiji, New Caledonia. To 10 in. high, 3 ft. wide; stems actually grow 3 ft. tall, but they arch over from weight of foliage. Tip-pinch early to induce branching; repeat to keep compact. Medium green, ovate, irregularly toothed leaves to 4 in. long. White or pale mauve flowers in 6- to 8-in. spikes are produced intermittently throughout the year. Leaves of 'Marginatus' (P. coleoides 'Marginata') are irregularly edged in creamy white. 'Green and Gold' has lime-green leaves with a neat gold margin.
P. madagascariensis. MINTLEAF. From southern Africa. Vigorous trailer reaches 1 ft. high; spreads 34 ft. wide initially, eventually much wider by rooting at leaf joints. Medium green leaves to 2 in. long are hairy, roundish, scallop edged; they smell like mint when crushed. Lavender-blue or white flower spikes in late spring, early summer. 'Variegated Mintleaf', the most commonly grown form, has irregular white leaf margins. Good ground cover to brighten shady areas. Often mistakenly sold as Iboza, another genus in the same family.
P. 'Mona Lavender'. Hybrid developed in South Africa. Multistemmed plant to 23 ft. tall and wide, with deep purple stems holding glossy, deep green, coarsely toothed leaves with purple-bronze veins and undersides. Leaves reach 2 in. long, 1 in. wide. Lavender-blue flowers with darker flecks, borne in 6-in. spikes, appear continuously in warm weather. Great as a bedding plant or grown in containers.
P. oertendahlii. MOSAIC SWEDISH IVY, ROYAL CHARLIE, CANDLE PLANT. From South Africa. Easy-care specimen for hanging basket or pot; most often grown as houseplant. To 812 in. high, with branches trailing to 12 ft. long. Roundish, irregularly toothed, velvety dark green leaves up to 2 in. long, with purple undersides and intricate network of silver veins. In autumn, white or light blue flowers bloom in loose, 8- to 12-in.-long spikes. Foliage of 'Uvongo' is more heavily netted with silver than that of the species; leaves of 'Variegatus' are irregularly edged in creamy white.
P. saccatus. From South Africa. Woody-based plant to 13 ft. high and wide. Green, almost canelike stems are set with fragrant, nearly triangular, bright green leaves with prominently toothed edges. Large blue to lilac (sometimes white) flowers bloom in midsummer.
P. verticillatus. SWEDISH IVY, CREEPING CHARLIE. From southern Africa. Typically grown in hanging basket or pot in the house or outdoors; also makes a good ground cover in a warm, protected spot. To 48 in. high, 46 ft. wide, with trailing branches. Waxy, shiny, dark green, scallop-edged leaves are roundish, up to 1 in. across. White or pale purplish blossoms in 8-in. spikes bloom intermittently all year. To grow as a ground cover, plant cuttings 12 ft. apart for quick coverage. 'Marmoratus' produces leaves irregularly marked with ivory.
Easy to grow. Stems take root wherever they touch the ground, and cuttings root quickly in soil or water. Remove flower spikes after they fade. Site houseplants in a bright window, but protect from hottest sun; keep moist, and apply a general-purpose liquid houseplant fertilizer monthly in spring and summer. Stop fertilizing and reduce watering in fall and winter.