Rhododendron ‘Stewartstonian’
Overview
Uses: Foundation plantings, low hedges, mass plantings, and part-shade beds.
Benefits: A hardy Gable hybrid azalea with clear brick-red flowers in mid to late spring. The glossy leaves turn wine-red in winter, giving it color well beyond bloom time.
USDA Hardiness Zones: 5–8
Sun: Partial Shade to Full Sun
Life Cycle: Broadleaf Evergreen Shrub
Growth Habit: Upright, Rounded — dense and full.
Bloom Color: Brick Red
Foliage Color: Glossy Dark Green, turning Wine-Red in winter
Mature Height: 3–5 feet
Mature Width: 3–5 feet
Bloom Season: Mid to late spring
Growth Rate: Moderate
Summary
A true brick red in spring and a deep wine red all winter.
Stewartstonian is one of the best-known Gable hybrid azaleas, a group bred in south-central Pennsylvania to bring reliable azalea color to gardens with real winters. In mid to late spring it opens clear brick-red to orange-red flowers that hold their tone rather than washing out, a strong, warm color that carries across a lawn and stands out against white dogwoods and spring bulbs.
Its second season is winter. As the weather cools, the glossy dark green leaves deepen to a rich wine red and hold that color until new growth starts in spring, so the shrub adds warmth to the garden in the months when most plants have little to offer.
The habit is upright, rounded, and full, reaching about three to five feet tall and wide. That makes it a good size to anchor the corner of a house, back up lower azaleas in a mass planting, or form an informal flowering hedge.
Like other azaleas, it thrives in partial shade or morning sun with acidic, well-drained soil.
Care
Stewartstonian Azalea Care
Plant in partial shade or a spot with morning sun and afternoon shade. Some direct sun produces the heaviest bloom and the best winter leaf color; harsh afternoon sun in summer can scorch leaves and invite lace bugs.
Give it acidic, well-drained soil rich in organic matter. The fine, shallow roots dislike wet feet, so in heavy clay, amend with compost or set the plant with the top of the root ball slightly above grade. Mulch with two to three inches of pine bark or shredded leaves, kept a few inches back from the stems.
Water deeply once or twice a week through the first growing season, and during dry spells after that. A thorough watering in late fall before the ground freezes helps the evergreen leaves come through winter without browning.
Fertilize lightly, if at all. One application of a slow release fertilizer for acid-loving plants, right after bloom, is enough.
Next year's flower buds form in summer, so prune only right after flowering. The full, rounded shape usually needs little more than removing an occasional out-of-place branch. A site sheltered from strong winter wind helps keep the foliage in good condition.
Size
What Size is the Stewartstonian Azalea for Sale Online?
Our Stewartstonian Azalea ships in a greenhouse-grade grow pot and is appropriately sized for its container at the time of shipment. Plants shipped in fall or winter may show wine-red winter foliage, which is normal for this azalea. If you have specific sizing or planting questions, please contact us.
How Large Does Stewartstonian Azalea Grow?
Expect about 3 to 5 feet tall and 3 to 5 feet wide at maturity, in an upright, rounded shape. Space plants about 4 feet apart for an informal hedge or mass planting.
Additional Information
What are some common names for this plant?
It is also sold as Stewartsonian azalea, a common spelling variant, and is grouped with the Gable hybrid azaleas.
What is a Gable azalea?
Gable azaleas were bred by Joseph Gable in Stewartstown, Pennsylvania, who selected for plants that could keep their leaves and flower buds through colder winters than many older azaleas tolerate. Stewartstonian takes its name from his hometown. See our full selection of Azaleas.
Why do the leaves turn red in winter?
Cold weather brings out reddish pigments in the leaves, and on this variety the effect is especially strong. The wine-red color is normal and the plant greens up again with new spring growth. For more shrubs that hold their leaves year-round, browse our Evergreen Plants.
Is Stewartstonian Azalea deer resistant?
No. Deer browse azaleas, especially in winter. Where deer pressure is heavy, protect plants with fencing or a repellent, or choose from our Deer-Resistant Shrubs and Evergreens.
