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Hardiest Azaleas and Rhododendrons

Deciduous Azaleas, Evergreen Azaleas, Lepidote Rhododendrons, Elepidote Rhododendrons

Hardy Deciduous Azaleas, Hardy Evergreen Azaleas, Hardy Rhododendron ,Hardy Azalea, Iron-clad Rhododendrons, Ironclad Rhododendrons, Ironclads

Gracing woodland gardens and shrub borders with their magnificent flowers, Azaleas and Rhododendrons are popular ornamental shrubs for gardens of all sizes. Evergreen or deciduous, these members of the genus Rhododendron come in all shapes and sizes, from small, ground-hugging shrubs to large, tree-like specimens. Their flowers range from the tiny and delicate blossoms of floriferous dwarf shrubs to the huge clusters or ‘trusses’ of tall growing hybrids and species. Some are fragrant, others feature a wonderful foliage adding glorious fall color to the landscape. All are fascinating but some varieties can tolerate severe winter conditions while others cannot.

The following list of Azaleas and Rhododendrons are exceptionally cold hardy and can withstand temperatures as low as -26ºF (-32ºC). They have all been recognized as proven performers and have received the Rhododendron of the Year Award of the American Rhododendron Society. Among them are some Iron-clads hybrids, which are regarded as the hardiest Rhododendrons and can tolerate open sites in sun (provided their roots remain moist).

Guide Information

Hardiness 3 - 9
Heat Zones 1 - 9
Plant Type Shrubs
Genus Rhododendron
Exposure Partial Sun
Season of Interest Spring (Early, Mid, Late)
Summer (Early)
Fall
Winter
Maintenance Low
Water Needs Average
Soil Type Clay, Loam, Sand
Soil pH Acid
Soil Drainage Moist but Well-Drained
Characteristics Plant of Merit, Showy
Tolerance Rabbit
Attracts Butterflies, Hummingbirds
Landscaping Ideas Wall-Side Borders, Hedges And Screens, Beds And Borders
Garden Styles City and Courtyard, Informal and Cottage, Japanese Garden, Traditional Garden

Hardiest Azaleas and Rhododendrons

Growing Azalea and Rhododendron

Remember that the ability to grow Azaleas and Rhododendrons successfully depends also on the site selection and soil preparation.

  • Their soil should be acidic, organic, moist, fertile, and well-drained.
  • Choose a site with dappled shade in sheltered conditions. Avoid deep shade beneath other trees. Most Rhododendrons will tolerate a more open site if sheltered from cold, dry winds. Dwarf alpine species will tolerate full sun provided the soil is kept evenly moist.
  • Many Azaleas and Rhododendrons are fully cold-hardy. However, a few of them have frost-resistant flowers. Any flowers blooming before the last spring frost are susceptible to damage. Since frost damage is generally caused when the early morning sun strikes the plants’ frozen tissues, you should site your Azalea or Rhododendron where both leaves and flowers are protected from the early morning sun and where they will adapt slowly to the increasing temperatures of the day. Since frost flows downward, avoid planting them in low-lying spots known as frost pockets.
  • When placing plants, always choose locations that mitigate extreme temperature changes, especially in spring and fall, and protect from drying summer or winter winds. Azaleas and Rhododendrons may be harmed in winter by frozen grounds and drying winds or bright sun, which will cause severe foliage desiccation. Protect their shallow roots with a mulch of oak leaves or pine needles and their foliage with woven material such as burlap screens. This will help prevent bark-split (when the sap running in the stem is frozen and bursts the bark).

Discover These Helpful Guides for Further Reading

Azaleas and Rhododendrons for Small Gardens
Azaleas and Rhododendrons with Attractive Fall Colors
Best Shrubs as Companion Plants for Azaleas and Rhododendrons
Choosing Perfect Azaleas and Rhododendrons
Extend the Blooming Season of your Azaleas and Rhododendrons
Fragrant Azaleas and Rhododendrons
Great Bulbs and Perennials as Companion Plants for Azaleas and Rhododendrons
Great Hostas as Companion Plants for Azaleas and Rhododendrons
Rhododendron and Azalea: How To Grow And Care with Success

Garden Examples

A Pretty Spring Border Idea with Rhododendrons and Tulips
A Pretty Spring Border Idea with Rhododendrons and Crocuses
A White and Blue Garden
Compare All Rhododendron
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Explore Great Plant Combination Ideas
Rhododendron
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Rhododendron
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.

Guide Information

Hardiness 3 - 9
Heat Zones 1 - 9
Plant Type Shrubs
Genus Rhododendron
Exposure Partial Sun
Season of Interest Spring (Early, Mid, Late)
Summer (Early)
Fall
Winter
Maintenance Low
Water Needs Average
Soil Type Clay, Loam, Sand
Soil pH Acid
Soil Drainage Moist but Well-Drained
Characteristics Plant of Merit, Showy
Tolerance Rabbit
Attracts Butterflies, Hummingbirds
Landscaping Ideas Wall-Side Borders, Hedges And Screens, Beds And Borders
Garden Styles City and Courtyard, Informal and Cottage, Japanese Garden, Traditional Garden
Compare All Rhododendron
Compare Now
Explore Great Plant Combination Ideas
Rhododendron
Guides with
Rhododendron

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