They are very slow growers and take from three to four years to grow flowers. Rhododendrons are seen in garden centers and grocery stores every spring, but they can be propagated from seed as well.

Germination will occur in ten to twenty days, and by about eight to ten weeks most seedlings will have developed their first true leaves. During this time nothing much needs to be done except to perhaps pluck out bits of seed debris that may show signs of mold or to thin seedlings, if sown too thick.

Rhododendrons (Rhododendron spp.) are flowering shrubs that are hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9, depending on the variety. The fastest-growing rhododendron cultivars grow 7 feet in 10 years, according to the American Rhododendron Society's website.

Many rhododendron plants grow from 3 to 4 feet in 10 years, but some can grow up to 7 feet in 10 years. Some of the fastest growing rhododendrons are the Brittenhill Bugle, R. genestierianum, Ilam Cream, Mother of Pearl, Professor Hugo de Vries, Spicy Nutmeg, and the Whidbey Island.. . . . .364011235570!]0000000000000009783314145144!]