Persian shield or Strobialanthus dyerianus is a tropical plant native to Myanmar. It is cultivated for its showy foliage in gardens in tropical and subtropical regions, as well as being suitable for greenhouse gardens. Nurseries in regions where this plant thrives may carry it and can order it by special request. Gardeners can also obtain it through cuttings and orders from mail order catalogs.
This plant is a low shrub that produces greenish-purple foliage with an iridescent overlay. The foliage is usually marbled and mottled with color. Small blue flowers are also produced, but many gardeners pinch them back to encourage the plant to focus on producing the distinctive and very colorful leaves. Persian shield can grow up to six feet (two meters) in height and is often trimmed back to make it a low shrub or groundcover.
By pinching back the soft, square stems, gardeners can encourage Persian shield to branch out and become shrubby. Untended plants can become leggy, with long, straight branches. These long branches can drop or break off with the weight of the leaves, in addition to developing a straggly and rather unsightly appearance.
Persian shield favors climates like those found in United States Department of Agriculture zones nine through 11, and will sometimes grow in zone eight. The plant needs high humidity and very rich soil. The soil should be well drained, and it needs to be kept moist to keep the plant healthy and happy. Persian shield has high water requirements and is not recommended for areas where there are water restrictions or concerns about drought.
Like many tropical plants, Persian shield is designed to live in the partial shade found under the canopy of trees and vines. It should be grown in a shaded and partially sheltered area of the garden. Trees and vines make excellent companion plants, as they will provide the shelter from the sun needed for Persian shield to thrive. In greenhouses, the plant should be positioned to get bright, indirect light. People can also try growing it indoors if their homes are warm, humid, and very bright.
In addition to being grown directly in the soil, this tropical plant is also suitable for container gardening. People growing the plant in containers can mix it with other tropical species, if desired. Container gardening can allow people to cultivate the plant in cool climates, as the containers can be moved to a warm, bright area free of drafts in the winter and then relocated outside in the summer months.