Rhododendron's Naked & Fancy Cousin
Common Name: deciduous azalea
Botanical Name: Rhododendron species & hybrids
Form: upright vase shape
Genus: Rhododendron, subgenus: Pentanthera
Species: 2 species and subsequent hybrids
Plant Type: deciduous shrub
Mature Size: 4’-8’ x 4’x8’
Origin: Eastern North America, Asia & Europe
Hardiness Zone: 4 to 10 depending on species
Foliage: emerge after flowers, green, elliptic, soft, hairy (pubescent), pinnate, narrow, up to 3” long, new leaves tinged bronze or red, then they turn purple, orange and red in autumn
Flowers: racemes of tube or funnel shaped, 5 petals, maybe double, held in clusters, spring, pink, orange, yellow, white, rose, salmon
Fruit: brown, capsules that slit open, hybrids are generally infertile
Stems: leaves are alternate on woody stems
Exposure: part sun to full sun (in temperate climates)
Soil: an acid rich (pH 4.5-6.0) moist soil with good drainage, add plenty of compost and a layer of mulch, do not like dry soil
Uses: attracts pollinators, fall colour, dear resistant
Propagation: seeds, layering, cuttings
Pruning: immediately after flowering, generally not needed
Problems: scale insects, spray with dormant oil in late winter
Deciduous azaleas are members of the rhododendron family. They are the odd guy out as, unlike their cousins, they are not evergreen. Their flowers are similar, except the deciduous azaleas bear colours that their counterparts do not. Instead of only red, white, pink and purple flowers, deciduous azaleas are neon bright in oranges, yellows, pinks, whites and reds. Some have ultra long stamens that resemble long eyelashes, and most are deliciously fragrant. Hummingbirds and butterflies love their sweet nectar and pollen.
Deciduous azaleas are members of the Rhododendron genus, subsection Pentanthera. Many species are hardier than evergreen rhododendrons and azaleas. Their form is delicate as their branches and leaves are smaller, thinner, and are sprinkled with soft foliage on airy stems.
Deciduous azaleas have two types of buds: flower cluster buds and leafy shoot buds. Flowers have five petals that flair out like trumpets. They only have 5 stamens, compared rhododendrons that have 10. Flowers are born in large clusters in trusses at the end of stems.
Blossoms appear in spring before the leaves do. They are the brilliant beacons in woodland gardens when other plants have yet to don foliage. Their simple, green, small soft hairy leaves turn brilliant colours in the fall, which adds another layer of interest.
Despite the lack of leaves during the winter, their bare stems look pretty good. Deciduous azaleas have an attractive upright spreading form and provide the garden with some good winter bones.
Care: Group deciduous azaleas together as understory planting among trees for a creative flower show. They love the dappled shade and bring light, life and attention to shady corners.
Azaleas are shallow rooted and must be mulched with 3 inches of an organic mulch. These are acid loving plants and need a low pH of around 5. Yellow foliage and lack of growth are sure signs that the soil pH is too high. Use compost, kelp and other organic plant food to promote an acid pH of 4.5-6.0. There are also acidifying fertilizers available specifically for acid loving plants. Refrain from fertilizing after July, unless the pH is high. Fertilizing after July may delay dormancy, which might contribute to winterkill. And don’t forget to mulch.
Here are a few of the numerous types of deciduous azaleas. Ensure they have moist soil with good drainage and not full afternoon sun especially when grown in the south.