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Those Elegant Azaleas &
Rhododendrons Spring is in the air.... ....and soon it will be time for those luscious azaleas and rhododendrons to begin their elegant and long-lasting displays. Now is the time to begin planning for the addition of these beauties to your landscape. I’ll address azaleas and rhododendrons together, because azaleas are actually members of the Rhododendron family, and basically share the same characteristics and cultural requirements, although some azaleas are better able to tolerate more sun. But more on this later. The Rhododendron family is quite large, with about 1000 species and many thousands of hybrids. It is true that most rhododendrons are primarily woodland plants, and originate in cooler climates than ours. But with so many hybrids from which to choose, and so much ongoing research and development of new cultivars from different parts of the world, we are seeing more and more choices available for those of us in Central Virginia (zones 6B and 7). Qualified Landscape Designers and the better nurseries in the area can provide you with lists of both rhododendrons and azaleas that do well in our area. Color selections range from white through various pinks, reds and purples, bloom sizes range from small to quite large, and bloom times generally range from April through May, sometimes a little into June. Certain native azaleas bloom late in the summer into fall. Most rhododendrons and many azaleas are evergreen, which makes them truly year-round plants for our landscape. And many mature sizes of this plant are available, so that you can use, for example, the low-growing, spreading evergreen 2 foot Gyokushin azaleas, which bloom late, in smaller garden areas, and use the early-blooming 6 foot high Delaware Valley White azalea in larger areas, perhaps further away from the house, in a more wooded site. Basically, choose the site first, then study the lists to determine the best fit. Don’t run out and buy an azalea or rhododendron off the shelf, just because it looks pretty, without determining its requirements and mature size! Unless you’re very lucky, neither you nor the plant will be happy in a few months. What makes members of the Rhododendron family happy? According to H. Edward Reiley, author of Success with Rhododendrons and Azaleas, the following are the basic requirements:
Perhaps the most asked question for these plants is “How do I know when I have the proper amount of light for my rhododendrons and azaleas?” As mentioned above, a general rule of thumb is that the larger the leaf, the more shade is required. So, in general, azaleas can tolerate more sun than rhododendrons. However, many factors can influence sun tolerance, including humidity, amount of precipitation, summer high temperatures, and number of cloudy days. “It is probably best to plant in as much sun as a specimen can tolerate without adverse effect. Plants will grow more compactly in sun, their stems seem to be tougher and more cold hardy, and they certainly set more flower buds. Conversely, plants in too much shade bloom sparingly and tend to grow tall and produce leggy flushes of growth with fewer branches.” Sound familiar? If you get this leggy growth, consider thinning some of the shade trees in the immediate area for the benefit of your shrubs. “The foliage of a plant getting too much sun will turn lighter green to yellow. As sun damage progresses the color change becomes more pronounced until edges or spots brown from completely dead tissue. The yellowing is a result of the rapid destruction of chlorophyll, a green pigment found in plant cells, due to heat buildup.” At this stage, of course, the plant is under such stress that it becomes easily vulnerable to insects and diseases. If you see this yellowing beginning to occur, I suggest transplanting the shrubs to a shadier site, and nurturing them until they recover. Members of the Rhododendron family are light feeders, and often it is not necessary to feed them at all. If you do, be careful not to overdo it, as their roots can burn easily. Start by ensuring that lots of organic matter is in the soil, and if you do feed, use an organic fertilizer with a light hand. Having developed in wooded areas, Rhododendrons expect plenty of moisture, but don’t like wet feet. The roots are rather shallow anyway, so drainage is important, but easily achieved. Feel free to call me for lists of azaleas and rhododendrons
for our growing area. Fresh Air
Garden Designs, (804) 449-1888 |