The enormous rhododendron family, which includes both rhododendrons and azaleas, contains many dwarf plants suitable for rock gardens, their specific use depends on their soil and light preferences and their habits of growth--compact, spreading or trailing. All the species and varieties listed here are evergreen and notable either for their foliage or flowers, sometimes for both. Most have oval leaves, dull or shiny; their flowers, bell-shaped or trumpet-shaped, usually bloom in clusters from early spring to early summer.
Examples of dwarf rhododendrons include: R. fastigiatum; R. indicum 'Balsam' (Balsam azalea); R. indicum 'Flame Creeper'; R. keiskei 'Dwarf' (dwarf Keisk rhododendron); R. kiusianum (dwarf azalea); R. nakaharai (dwarf azalea); R. racemosum 'Dwarf' (dwarf Mayflower rhododendron); R. hybrids 'Dora Amateis', 'Moerheim', 'Purple Gem'. All are called dwarf rhododendrons or dwarf azaleas. [Return to Top]
R. fastigiatum; R. keiskei; R. kiusianum (dwarf azalea); R. nakaharai; and R. racemosum are all dwarf rhododendrons hardy to Zone 6, -10 to -5° F while R. indicum is hardy to Zone 7, 0° F.
R. fastigiatum, a dwarf lepidote rhododendron, has shiny blue-gray leaves, 1/2 inch long, and bell-shaped lavender-rose flowers 1 inch wide. It is an open, upright plant, becoming 3 feet tall with a spread of 12 to 24 inches.
R. indicum 'Balsam' (Balsam azalea) and R. indicum 'Flame Creeper' azaleas are prostrate plants that form low mounds up to 4 feet across; they are useful as ground covers. Both have dull, hairy leaves, 2 inches long. The salmon-pink double flowers of 'Balsam' resemble roses, while those of 'Flame Creeper' are an intense scarlet.
R. keiskei 'Dwarf' (dwarf Keisk rhododendron), a dwarf lepidote rhododendron, bears pale yellow 2-inch bell-shaped flowers and has olive-green 2-inch leaves that turn wine red in winter. It is a spreading plant, growing 2 1/2 feet tall and 4 feet wide.
R. kiusianum (dwarf azalea) and R. nakaharai (dwarf azalea) are both dwarf azaleas. R. kiusianum blooms while still young, bearing white, pink, rose or purple flowers 1 to 1 1/2 inches across. The shiny 1-inch leaves sometimes turn red in winter. This open, twiggy plant grows slowly to 3 feet tall and 5 feet wide. R. nakaharai forms a low dense mound that seems to grow flatter as it matures, since its ultimate height is 6 to 9 inches, while its spread is 12 to 15 inches. The small, shiny leaves, 2 inches long, are hairy on the undersides. The 3-inch pink, salmon or red flowers are saucer shaped and, unlike most azaleas, open in midsummer.
R. racemosum 'Dwarf' (dwarf Mayflower rhododendron), a dwarf lepidote rhododendron, is a spreading semi-prostrate plant 2 feet high and up to 5 feet wide, with many-branched wiry stems. The 3/4-inch white or pink flowers begin to appear while the plant is still quite young. The 2-inch leaves are smooth on the top, gray and scaly on the underside.
Here are some popular dwarf rhododendron species that only grow to about 1 foot tall in 10 years.
|R. calostrotum ssp. keleticum||
|Rose purple pansy-like flowers, semi-prostrate with small shiny leaves.|
|Small, dark green leaves; small, bell-shaped flowers; compact, upright growth.|
|R. forrestii ssp forrestii||
|Prostrate, very slow growing. Bright red flowers. Deep green leaves are rounded.|
|Excellen dwarf, tight compact habit, silver-gray foliage, bright blue-purple flowers.|
|R. keiskei var. ozawae||
|Good foliage & habit, forms a neat mound covered with masses of lovely yellow.|
|Heavy flowering orchid pink, cute plant, easily grown and free flowering.|
|Prostrate, gnarled, bell-shaped flowers are creamy yellow with crimson spots.|
|Slow growing, indumentum, bell-shaped pink flowers with crimson spots.|
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Dwarf Hybrid Rhododendrons
R. hybrids 'Dora Amateis', 'Moerheim' and 'Purple Gem' are all dwarf hybrid rhododendrons hardy to Zone 6, -10 to -5° F. 'Dora Amateis' grows 3 to 4 feet tall and has 3-inch white flowers speckled with green; its leaves are dark green and in full sun have a bronze sheen. 'Moerheim' is a low, dense shrub, growing 3 feet high and 3 feet wide; it has 1-inch violet-to-purple flowers, and 2-inch shiny green leaves that turn maroon in the winter. 'Purple Gem' forms a dense mound and grows 1 1/2 to 2 feet tall; this variety has 2-inch lavender-to-purple flowers and 2-inch blue-green leaves that turn rust-colored as they age. [Return to Top]
Here are some popular dwarf rhododendron hybrids that only grow to about 1 foot tall in 10 years.
|Carmen||-5° F||Emerald green round leaves. Buds as a young plant. Dark red Flowers.|
|Egret||-5° F||Each terminal is has miniature white clusters forming a snowy white ball.|
|Ernie Dee||0° F||It will grow in width. Purple, lightly frilled flowers are long lasting & plentiful.|
|Lemon Dream||0° F||Abundant, frilly, lemon yellow flowers, dark green rounded foliage,indumentum.|
|Lori Eichelser||-5° F||An outstanding hybrid, round deep jade-green leaves, cherry-pink flowers.|
|Princess Anne||-5° F||Yellow flower with slight greenish cast. Foliage turns shades of bronze.|
|Ptarmigan||-5° F||Showy, pure white, small flowers, develops naturally into a finely textured mound.|
|Tow Head||-15° F||Brilliant greenish yellow flowers with orange-yellow spotting. Will grow in width.|
In cold climates, most do better on the north side of a building or on a northwest slope. All need some sun for best flowering but in general require partial shade. They thrive in a moist, well-drained, humus-filled soil with a pH of 5.0 to 6.0, enriched with peat moss or leaf mold. Plant dwarf rhododendrons and azaleas in spring or, in areas that have mild winters, in the fall. Prepare the soil by thoroughly mixing equal parts of loam, coarse sand and ground oak leaves or redwood. Plant the root ball slightly higher than it was growing at the nursery.
To keep the soil cool and moist, mulch it with a 2-inch layer of wood chips, ground bark, pine needles or coarse peat moss. Fertilize plants in the early spring with a light sprinkling of cottonseed meal or a fertilizer specially formulated for acid-loving plants. Pruning is seldom needed except for removal of faded flowers, but if it is, branches may be trimmed immediately after flowering. Rhododendrons may be harmed in winter by drying winds and bright sun; protect their shallow roots with a mulch of oak leaves or pine needles and their foliage with a loose blanket of evergreen boughs or specially built screens.
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