Rhododendrons and Azaleas

• Quintessential Spring blooms in a huge range of colors
• Gamut of shrub sizes, from tiny to tall and broad
• Evergreen and deciduous types
• Can be fragrant
• Well-chosen selection will bloom early Spring into Summer

Local Advice for Local Gardeners

What would Spring be without the glorious blooms of rhododendrons and azaleas? With flamboyant flowers in any color you choose, and with a good selection of varying bloom times, you can have a long display, even into Summer, changing the mood with different color schemes. Plant sizes vary from dwarf to 12ft (and even more), their leaf color encompasses a wide range of greens (including bluish and variegated) often with orange-, bronze- or silver-tinted undersides. All make great companions with plants needing similar conditions, such as Japanese maple, mountain laurel, and ferns.

What’s the difference?

To the botanist, azaleas are a type of Rhododendron but to gardeners the distinction is that azaleas are generally smaller-leaved, deciduous or evergreen, with smaller, funnel-shaped, exceptionally colorful flowers while rhododendrons are always evergreen and produce massed globes of huge flowers to clusters of tiny flowering bells.

Choose from these types

• Large-leaved rhododendron, with thousands of hybrids in almost every color
• Small-leaved rhododendron, with many color combinations
• Evergreen azalea, in all flower shades but yellow
• Deciduous azalea, often combining color (including yellow), fragrance, later bloom and autumnal foliage
• Native species, such as R. maximum, R. periclymenoides, R. viscosum
• Dwarf, in both rhododendron and azalea, evergreen or deciduous
• Unusual features, such as variegated leaves or intense fragrance

Rhododendrons and azaleas like

• Soil - All require well-drained soil high in organic matter – and it must be acid. pH 5.5 is ideal (if in doubt, use a test). If your soil is more alkaline add ferrous sulfate or agricultural sulfur
• Light - Happiest in dappled sunlight, preferably morning sun and afternoon shade; try to avoid South and West-facing spots
• Moisture - Keep new plants well-watered; keep older plants moist (not wet). Waterlogged soil is the number one killer
• Remember Rhododendrons are shallow-rooted, so avoid planting too deep, drying them out, or digging around them.
• Also Small-leaved and deciduous types can take more sun, but protect all from drying winds with other plantings

Where to grow rhododendrons and azaleas

• Woodland gardens - Perfect as understory plants under tall trees
• Specimens - Ideal free-standing shrub as spring focal color
• Landscapes - Dramatic as mass plantings lined with bulbs for spring
• Low hedges - Compact slow-growers can edge the driveway
• Rock gardens - Dwarfs are a natural with alpines
• Containers - Impressive in a large, lovely pot and can be moved after blooming
• Mixed borders - Dwarf types are lovely as foreground border plants, while taller evergreens make excellent background shrubs

Seasonal care

• Spring - Best planting time is early Spring. Pre-soak the rootball. Never plant too deep – keep the top of the rootball at, or 1-2in above, soil surface. Don’t fertilize until after flowering, before the end of June, sparingly with acid fertilizer. Prune minimally after blooming. Remove old flowers for best next bloom. Mulch
• Summer - Keep well watered during driest times, adding 2-4in mulch to protect from Summer heat, especially in the first year. Taper off watering in August
• Fall - Secondary planting time in mid-Fall. Cease watering before the Winter freeze. Provide deep coarse mulch year-round
• Winter - If plant is often injured by Winter, choose another, hardier, variety

Terrain’s Top Ten Rhododendron

Early:

• ‘Ben Morrison’ (evergreen; orange-pink and white bicolor)
• ‘Mary Fleming’ (small-leaved foliage turns bronze in winter; cream and pink flowers)
• PJM Group (small-leaved; lilac-purple)

Midseason:

• 'Gibraltar' (deciduous; fragrant copper-orange)
• ‘Janet Blair’ (large-leaved; frilly light pink and gold)
• ‘Percy Wiseman (large-leaved; white with yellow throat, with pink and red buds)

Late midseason:

• ‘Cannon’s Double’ (deciduous; yellow and pink double)
• 'Goldflimmer' (large-leaved; variegated bright yellow down the center, with lavender-purple and yellow flowers)
• ‘Northern Hi-Lights’(deciduous; fragrant yellow and white)

Very late: