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Wednesday
Dec092015

Deciduous Azaleas: Garden Royalty

Fall Color of Exbury Azalea

Fragrant Spring Flowers in Bright Tropical Colors in shades of white, pink, red, orange, and yellow

The deciduous azaleas are known for sweetly scented bright spring flowers and vivid orange, yellow, and red tinted fall foliage.  These long lived perennial bushes are winter hardy through USDA Climate Zone 5; the cold resistent Northern Lights strain from Minnesota are hardy to Zone 4 and some even to Zone 3! Their upright bare branches in winter are topped by interesting buds which contain the next spring's flowers, which also makes them resistent to damage from ice storms in the Midwest, such as often happens in Missouri, Arkansas, and even out West in the Columbia Gorge in Oregon.  Unlike evergreen rhododendrons, these azaleas can be coated in ice and the weight of snow will never weigh them down to break their bare branches.  An unusual trait for being in the rhododendron family is after they are done flowering and are pruned new buds will form anywhere along the pruned stem near the cut, unlike most rhododendrons that sprout only at the growth nodes.  This trait makes deciduous azaleas easier and quicker to prune.  These ericaceous plants need soil conditions on the acid PH side, just like blueberries, which make a nice edible companion plant for them.  The soil MUST be fast draining, have high organic content, and be on the acid side.  Add sulphur to lower the PH (Potential Hydrogen) in the soil near concrete foundations which may be alkaline.  NEVER use aluminum sulphate to lower the PH as this will cause an eventual toxic builup of aluminum in the soil profile.  Do not cultivate deeply around these azaleas as their roots are near the surface, mulch them with a surface layer of bark or acidic pine needles instead.  Site these beauties in partial shade as too much shade will make for lanky plants with few flowers.  In cool summer western Oregon they can be planted in full sun for increased flowering, but my planting in hot summer Missouri requires some shade and as such are planted on the northeast side of my house.  Check the summer heat index for your planting zone along with the minimum winter temperatures.  My personal collection currently numbers 21 plants, which is a lot of ground covered considering they predominantly grow 4-6' tall by 3' wide and are about 4' from each other for good air circulation.  Many of the Exbury types of these plants were developed and collected by the Rothschilds in England and there are other large collections here in North America at such places as the Biltmore Estate; so these plants really are garden royalty with a following from discriminating gardneners wolrdwide.  The deciduous azaleas will not be happy in the hot desert but will be at home in most situations in United States USDA zones 5-8.  They are prone to powdery mildew on the foliage some years, but are mostly a low maintenance plant.  Fertilizing lightly spring with cottonseed meal is best, while ammonia sulphate is adequate.  I just love the sweet fragrance and vivid colors of the beautiful deciduous azaleas! To purchase named clones of tried and true deciduous azalea cultivars note the flower appearance in the spring but purchase plants in the late fall.  Nurseries and garden centers have a hard time selling them in the fall when they are bare of leaves and flowers, this is the opportunity to buy these expensive plants at bargain prices.  In the USA you may be able to save over 63% purchasing them in late fall instead of spring when they are in bloom; for example a $ 30 plant will usually sell for around $ 10 USD.  Plant them as soon as you receive them in a previously prepared bed or other location.  I imagine it would be a similar bargain situation for purchasing these plants in England, Europe, and New Zealand during the end of the season.  God speed and don't forget to give Yahweh the honor for the knowledge and skill plant breeders have in refining these pleasant flowering shrubs that help make our world in which we live even more beautiful: HalleluYah! (Praise Yahweh!)  Douglas

They can also be grown in large containers on a deck or patio