Description & Growing Deciduous Azalea

• All Azalea are Rhododendron but not all Rhododendron are Azaleas. Now we have that as clear as a muddy pond what is an Azalea?
• An Azalea can be an evergreen or deciduous flowering shrub with pale or startling coloured blooms.
• Some Azaleas are scented whilst others are without scent. Whatever you think about deciduous Azaleas, ‘muddy and boring’ they are not.
• Azalea are some of the most gay and brilliant flowering shrubs yet grown.
• For the technically minded Azaleas are in the genus Rhododendron, with evergreen azaleas in the subgenus Tsutsusi and deciduous azaleas in the subgenus Pentanthera.
• Most deciduous azaleas are hardy but asiatic species need more protection when young

 

 

Varieties & Hybrids of Deciduous Azalea for Growing

• The species have been much crossed and bred but the scented Rhododendron luteum and Rhododendron japonica are available as species.
• Knapp Hill hybrids are amongst the most colourful deciduous Azaleas.
• The Ghent hybrids have sweetly scented, honeysuckle-shaped flowers with long stamen emarging from the tube.
• The Rhododendron Mollis Azaleas are crossed between Rhododendron mollis and Rhododendron japonicum
• Rustica hybrids have fragrant double flowers and Occidentale hybrids flower in late May
• The Exbury range were bred by Lionel de Rothschild who loved deciduous azaleas and carried out much breeding work to enhance colours and scent. The Solent Range was started by George Hyde a private grower in Dorset but bought for Exbury (Images).
• For specimen plants Azalea Coccinea Speciosa or R obtusum are recommended

Cultivation and Soil for Deciduous Azalea

• Azaleas need a moisture retentive, acid soil, pH 4.5-6.0 is best. Prepare the soil well and over a good area as the plants will be in-situ for many years.
• Roots are fibrous and tend to be near the surface so don’t hoe too closely
• Azaleas are relatively pest-free, forgiving and easy to grow plants. They like to be mutually supporting so closer planting (say 3 feet for stronger growers) is better for general health.
• They adapt to sun or partial shade with flowers fading within 2 weeks if in full sun.
• Mulch with at least an inch of peat, pine bark or wood chips to keep moisture in the ground, allow air into the soil, even out changes in the soil temperature and keep weeds down.
• Young azaleas grow quickly then mature at up to 5 feet tall

Cultivation and Watering for Deciduous Azalea

• Azaleas like moist soil at their roots. This may require supplemental watering at least until plants are established in the ground for a few years.
• Adequate water after flowering helps to produce more flower buds for next year.
• An infrequent deep soaking is more effective than superficial sprinkling. If the Autumn has been dry water well before winter.
• Azaleas do not like “wet feet”. Good drainage can be provided by planting azaleas with the tops of their root balls a few inches above ground level and mounding the soil up to the plants particularly on heavy clay soil. Moss growing on the soil is an indication of chronic bad drainage.

Hybrid Varieties

• Apricot Sunrise , Niamh, Norma – cerise or deep pink in colour.
• Narcissifolium – lemon, Hangers Flame – light orange
• Homebush, Bridesmaid white Irene Kostler and Jock Brydon light with pink outer to petals
• Fireball – red

Unusual Facts about Deciduous Azales

• As a woodland tree Azaleas except Mollis hybrids like shade and the flowers last longer.
• Flowers start before the leaves are fully open

Old & Odd Tips From Gardeners Tips

• More sun typically produces a more compact plant. You may get more blooms but they will not last as long.
• Established azaleas do not need fertilizer but a little sulphate of ammonia in spring gives a nitrogen boost and water in potash if flowering is poor. Undertake any fertilising in late winter or early spring so you do not encourage sappy growth that may be killed in a cold winter.

‘Azaleas are flowering shrubs comprising two of the eight subgenera of the genus Rhododendron, Pentanthera (deciduous) and Tsutsuji (evergreen). Azaleas bloom in spring, their flowers often lasting several weeks. Shade tolerant, they prefer living near or under trees.’

Horticultural Sources and Links about Deciduous Azaleas

• Glendoick in Scotland is a great nursery specialising in Rhododendrons and they have some grand Deciduous Azaleas
• Burncoose Gardens Burncoose Gardens
• Cally Gardens Cally Gardens in South West Scotland)
• Glenwhan Gardens Glenwhan Gardens

Photo Credits
Deciduous azalea by Eric Hunt CC BY-NC-ND 2.0
Rhododendron occidentale #4 by J.G. in S.F. CC BY-NC-ND 2.0
Orange deciduous Azalea by wallygrom CC BY-SA 2.0
Azalea by dmott9 CC BY-ND 2.0
Azalea Berry Rose flower by Herms56 CC BY-NC 2.0