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Azaleas are worth the extra trouble

Azaleas have been available as winter houseplants for decades, but their popularity seems to have always lagged behind that of poinsettias or amaryllis.

Azaleas have been available as winter houseplants for decades, but their popularity seems to have always lagged behind that of poinsettias or amaryllis. They're at their peak for almost the same period, but their requirements are more exact and they have never been as iconic. Yet they offer their own unique freshness.

Most of the azaleas found in florist shops have been developed from Rhododendron simsii, native to China. The original species grows at an altitude of 1,600 to 9,000 feet in a cool, moist environment in acidic soil, forming the understory below tall trees. The species is an evergreen shrub reaching up to 6.5 feet in height with oval leaves and fluted flowers ranging from white to dark red.

From Canton or Hong Kong, it made its way to Europe. Much of the early hybridizing was carried out in Belgium, France and Germany. Today, its hybrids are about 18 inches in height and spread and are available in wide colour range including red, pink, white, purple, rose, salmon, crimson, violet and bi-colours. The flowers are in small clusters of two to five and may be single or double.

By the reign of Queen Victoria, it had entered the British parlour. The Victorians loved azaleas and went on to develop hundreds of additional hybrids. It suited their homes perfectly. A lack of central heating made cooler night temperatures the norm. Britain is often humid and lace curtains provided indirect diffused lighting. And if one was fortunate enough to have a parlour in that era, there was generally also a gardener to look after plants.

Our homes, though well suited to the prairie climate, are not as well suited to potted azaleas. Their requirements include cooler temperatures, filtered sun, frequent watering, misting to prevent the buds from drying out and acidic soil.

A temperature of 15 to 18 C will prolong flowering. Not easy in a modern home, but there may be a north or east wall which may be a bit cooler than our normal 21 C. Also keep in mind that hot air rises, so the lower the plant is placed, the cooler it is likely to be. Any bright area not in direct sunlight will most likely qualify as "filtered light," especially during the winter. By placing the pot on a tray of pebbles, small rocks or marbles filled with water, you will be promoting a higher humidity. Misting will also increase the humidity. Never allow your azalea to dry out. Check it daily. If the media in which it is planted appears dry, water it. Remove the blossoms as they fade.

When selecting an azalea, look for one with only a few flower buds already open. Leave those with all tight unbroken buds or those already in full bloom. The flowers should appear healthy and be at different stages of development. Check the leaves. If yellowed or the undersides have evidence of whiteflies, spider mites or mealy flies in residence, don't take it (or them) home. Blooms should last about two to four weeks. The warmer the room, the shorter the bloom period.

If you share your home with toddlers or pets who are prone to eat houseplants, please note that azaleas are toxic. Both their leaves and flowers contain andromedotoxins. (Azaleas and rhododendrons were once so infamous for their toxicity that to receive a bouquet of their flowers in a black vase was a well-known death threat.)

Sara is the author of numerous gardening books, among them the revised Creating the Prairie Xeriscape. And with Hugh Skinner: Gardening Naturally; Trees and Shrubs for the Prairies, and Groundcovers & Vines for the Prairies. Expect Fruit for Northern Gardens with Bob Bors in November, 2017. 

— This column is provided courtesy of the Saskatchewan Perennial Society (www.saskperennial.ca; hortscene@yahoo.com; www.facebook.com/saskperennial). Check out our Bulletin Board or Calendar for upcoming garden information sessions, workshops, tours and other events.