Althea, also known as Rose of Sharon or Hibiscus syriacus, is a popular blooming woody shrub in cold hardiness zones 5 to 8. Altheas love the heat and blooms in the summer as many other plants are winding down their flowering season. Altheas are members of the hibiscus family, and the single or double blooms closely resemble the tropical hibiscus blooms, and come in a variety of colors. These plants are upright, growing taller than wide and are covered in compact green leaves. Altheas are different that the plants termed ‘hardy hibiscus’, which are herbaceous perennials that die back to the ground winter and emerge in the spring. Prune in late fall or early spring; flowers grow on new wood (meaning the current season’s new growth) and yearly trimming will encourage fewer but larger blooms.
- Sun to Part Sun
- Summer blooming
- Drought tolerant once established
- Eye catching blooms
- Plant in fertile, well-drained soil
Landscape features include large, summer blooms and dense shape if kept trimmed.