Evergreen wisteria (Millettia reticulata) is a sprawling, spreading evergreen vine characterised by leathery green leaves and an abundance of fragrant, pea shaped flowers. The plant is not cultivated as commonly as Chinese wisteria (Wisteria sinensis) or Japanese wisteria (Wisteria floribunda), though it may be grown as an ornamental in warm climates.
Evergreen wisteria grows to a height of up to 15 feet, with a spread between 3 and 6 feet. The shrub produces 6- to 8-inch panicles of pealike, long-lasting flowers in late spring or early summer. Flowers may be pink, red or blue and have a distinct camphor-like fragrance.The plant does not have an aggressive growth habit, unlike the more common Chinese wisteria.
Evergreen wisteria requires full sunlight to thrive. A minimum of six hours of direct sunlight is sufficient. The plant is a suitable landscape plant for USDA hardiness zones 7 to 10. Once mature, the plant will need structural support, as it becomes very heavy. A trellis, arbor, pergola or even a well-established living tree may be used. Plant in a sheltered location to protect from wind.
Plant evergreen wisteria in a well-draining soil enhanced with peat moss, compost or manure. The plant prefers a soil pH between 6.0 and 7.0. Mulch well in the winter to maintain soil temperature and suppress spring weeds. If winter temperatures are severe, protect the plant with burlap. Fertilise throughout the growing season with a water-soluble fertiliser. Water regularly as well, especially during summer dry spells.
Wisteria is not subject to many pests and diseases, though it may not bloom regularly. Plants may not bloom if grown in locations that are too shady, or if the plant is over fertilised with a nitrogen-rich fertiliser. Pruning too heavily in the winter and spring may also prevent flowering. Gardeners can encourage the vine to flower by applying a heavy application of superphosphate in the spring. Mature wisteria plants will struggle if replanted.