Azaleas are among some 1,024 woody species of heath plants in the Rhododendron genus of the Family Ericaceae. Rhododendron origins date to about 70 million years ago, but species distribution has been reduced, isolated and affected by ice ages, continental drift, evolution of grasslands and deserts, climate change and, most recently, human factors. Gardeners consider rhododendrons to be taller shrubs and small trees with large leathery evergreen leaves. The azalea group of rhododendrons contains smaller shrubs with small thin leaves that are often deciduous. Bigger rhododendrons usually have larger flowers with 10 stamens while most smaller azalea flowers have five stamens.
Most rhododendron species originated in Asia, where new-to-science species are still being identified. North America now has about 26 native species of rhododendrons — all from sheltered montane forest regions, including the Appalachian Mountain chain, the Pacific Northwest and California. Rhododendron is the state flower of Washington and West Virginia; state tree of Sikim and Uttarakhand in northern India; provincial flower of Jiangxi in China; and the national flower of Nepal.
The large, leathery-leaved, taller, evergreen rhododendrons are not marketed in Florida as they cannot tolerate our summer sun, torrid heat, high winds or torrential summer rainy season. Small-leaved azaleas are a coveted ornamental and can grow well from Central Florida northward. If homeowners want beautiful flowering azaleas to flourish in warm subtropical-to-temperate, Florida they first must consider the plants’ needs.
All shallow-rooted azaleas need humus-rich, moisture-retaining, acidic soil that is well-drained and never soggy. Well-drained sandy soil can easily be amended to 8 inches deep with the finely milled yard waste mulch available free at Central Landfill on State Road 44 west of Inverness. They do not like alkalinity leaching from limestone or concrete foundations, home pads or paths. As hot summer sun can burn azalea leaves, these ornamentals benefit from part shade under a canopy of taller trees.
There are over 10,000 named azaleas cultivars and hybrids developed by plant breeders globally. While older cultivars bloom for about 30 days in late winter to early spring, there are seasonal blooming azaleas like red ruffle, pink ruffle, fashion, and Encores. The ruffle and fashion azaleas bloom two or three times a year. The unbeatable, multi-season, repeat-blooming Encore brand flowers up to six months from late summer to early spring. Be aware that a hard freeze will kill open flower petals.
Louisiana plant breeder Robert E. Lee “Buddy” crossbred the ‘Fourth of July’ summer flowering cultivar with hardy manmade hybrids that bloom in the fall. Lee patented his resulting seedlings that are heavy summer, fall and spring bloomers.
My sandhills, Central Florida, zone 8b–9a garden has only repeat-blooming Encore azaleas. I tried older varieties of ruffles, fashions, tabors, geberrings and formosas, but prefer the long and spectacular flowering season of the repeat bloomers. Starting about eight years ago, I planted about 40 Encore azaleas from 6-inch pots. I am currently amending planting beds for many more. Gardeners should browse http://www.encoreazalea.com for charts detailing growth habit, flowering season and flower color.
These repeat-blooming dwarf azaleas have a fixed height and spread (diameter) of either 3 by 3 feet or 5 by 5 feet. They never actually need pruning. Prune only immediately after all flowering has ceased in spring only. If pruned too late, the developing flower buds will be cut off.
It is critical to create humus-rich soil well before planting azaleas. Prepare the planting bed, then choose the height for the specific site before choosing the color. With 31 current varieties, there is something for every homeowner. Repeat-blooming azaleas can be used as understory, background, border, foundation, evergreen privacy screens, specimens and even kept in large planters on a shaded lanai or patio. Be sure the soil is humus-rich, moisture-retaining and not alkaline.
On cold winter mornings, it is a pleasure to browse gardening catalogs and online sites. It is sad to see a hard freeze kill flower petals, but these hardy ornamental plants will rebloom within weeks after a freeze. As most ornamental azaleas are sterile hybrids, they rarely develop seeds.
Jane Weber is a professional gardener and consultant. Semi-retired, she grows thousands of native plants. Contact her at email@example.com or phone 352-249-6899.