Rhododendrons and Azaleas have long been the go-to plant for northwest gardens. They love it here, so it’s an easy choice.
There is a large group of them however that has been overlooked for years; the ones that lose their leaves in winter. Dramatic flower color and sweet perfume, lovely fall leaves and self-sufficiency are some of their best qualities. Plus they thrive in sunshine while their evergreen relatives burn.
Many of the plants listed below were bred from Azaleas that are native to the United States. Knapp Hill Nursery, Goldsworth Old Nursery and Exbury began to hybridize in the late 1800s using Rhododendron calendulaceum and Rhododendron arborescens (both native to eastern U.S.), Rhododendron occidentale (native to the Pacific Northwest), and Rhododendron molle (native to China). Many of their hybrids are still sold today. Locally Ivan and Robertha Arneson used those hybrids to breed new Azaleas into the 1990’s. Arneson Azlaeas are now some of the best and most popular on the market.
The Crystal Springs Rhododendron Garden near Reed College is a wonderful place to see deciduous rhododendrons in bloom in spring.
Red flower buds open to yellow-orange flowers w/ red edges, disease resistant leaves, maroon color in autumn. Grows to 3’ x 4’. Zone 5.
Cream, gold and pink double(many petals) flowers. New leaves have a bronze cast & turn green in summer. Upright, open & airy growth to 5’ x 6’. Hardy Z5.
Slender & elegant white flowers with intense sweet fragrance and frosty blue-green leaves that turn orange and red in fall. Grows to 4’ x 4’. Hardy Zone 5.
Red flower buds, deep orange flowers w/ gold tinge on the upper lobe. Leaves are mildew resistant. Grows to 4’ x 4’.
Orange flower buds open to gold flowers. New leaves are tinged with bronze and turn green in summer. Grows to 4-6’ tall, 3-5’ wide, Zone 5.
Red-orange flower buds open to only slightly lighter orange flowers. Grows to 5’ x 4’. The ‘Lights’ series is more cold tolerant than other Deciduous Azaleas, hardy to Zone 4.
White flowers with a strong yellow blotch on the upper petal. Blooms at the same time that leaves appear, a bit later than others. Grows to 4’ x 3-4’, Hardy to Z4
Native to Oregon and California coastal areas – Flower color varies on plants found in the wild, or in plants grown from seeds. White, pale pink, yellow to orange or combinations of all of these colors are common. Flowers have a sweet honeysuckle-like scent and bloom in mid April to early May. Leaves are green and turn yellow, orange and red in fall. Growth is more compact than many other deciduous Azaleas, to about 3-5’ with a more dense shape. Hardy to -5f.
Year-round with best selection in April & May
Family: Ericaceae
Genus: Rhododendron
Common: Deciduous, Exbury, Mollis, Western, Sweet, Coast Azalea
Origin: Eastern & Western North America, Asia & Europe
Characteristics: All Rhododendrons & Azaleas included in this article lose their leaves during winter. Rhododendron flowers can be white, pink, yellow, orange, red or a combination of several colors. Most are sweetly fragrant. Some flowers are tube-shape, others are funnel-shape and some are double, having extra petals. Bloom time is from late winter to mid spring.
Leaves open with the arrival of flowers or just following bloom. Most are green but some are frosty blue-green and both types display excellent orange, red & purple color before falling in autumn. Some display bronze or red-tinged new leaf growth.
Size: Most grow to around 4-5 feet tall x 5-6’ wide, but can get larger given time.
Culture: Unlike their evergreen relatives, deciduous Azaleas and Rhododendrons thrive in full sun. Part-shade to shade is fine too. Plants grown in more shade will have an open airy shape and fewer flowers than plants grown with more light.
Any Rhododendron or Azalea prefers well-drained soil with an acidic pH. The Pacific Northwest naturally has soil with low pH because of copious rain, but much of the area has heavy clay soil, so mixing compost to the bed before planting is advised. Rhodies and Azaleas have shallow root systems and prefer a thin layer of mulch, under 1".
Fertilizer used should be specific to acid-loving plants, and directions should be followed carefully.
Problems: Enemy number one used to be powdery mildew, but now Portland has a pest called Azalea Lace Bug, which sucks chlorophyll from the inside of the foliage, leaving white or coppery stippling.
Treating Powdery Mildew: Most Deciduous Azaleas and Rhododendrons are subject to powdery mildew on leaves during the warmth of summer. It's a good idea to clean up effected leaves after they've fallen off in autumn, and add a light layer of mulch to cover spores that may be laying about on the ground. Options for treatment are many and include:
Treating Azalea Lace Bug: The good news is that deciduous azaleas and rhododendrons are not the Lace Bug's first priority. Azalea Lace Bugs lay their eggs inside the leaves of evergreen azaleas in fall, where they stay protected through the winter and hatch in late spring. Since deciduous azaleas and rhododendrons lose their leaves, they can't support eggs over winter. Most damage deciduous azaleas receive comes from adult Lace Bugs who have eaten up all the evergreen azaleas in the neighborhood and are moving on to other delicacies.
Read up on some of our favorite shrubs and remember, this is only a smattering of the variety of shrubs we carry all year long! Note: Viewing a Native Plant will take you into our Native Plant section.
