Beautiful azaleas in bloom in the spring apparently cause many homeowners to want to plant some of them. Many have asked if it can be done in mid-to-late spring. Those that are evergreen and not great big can be planted and transplanted almost any time of the year except when the ground is frozen or the soil is too wet for digging.
They grow well throughout the Appalachian Mountains and in the states along the Atlantic and Gulf coasts. They do well around Lake Erie, in the southern Mississippi Valley, and along the Pacific Coast from Puget Sound to San Francisco Bay.
Soils or climate in the rest of the United States may be unfavorable for them. They can be grown in unfavorable regions but they need more attention than in favorable areas.
Some kinds of azaleas will survive colder winter temperatures than other kinds. Some will withstand hotter summer temperatures than others. Before you buy azalea plants, be sure they are varieties that will grow satisfactorily in your area.
In the north, the best time to plant them is early spring and in the south from fall to early spring. They can be planted while they are growing but it needs to be done carefully. Many are sold in the spring when they are in bloom. They will do all right if shaded from the hot sun and kept well watered for several weeks until they become established in the new location.
Azaleas do not grow well in dense shade; they become spindly and bloom only sparsely. They will grow satisfactorily in full sunlight but do better in moderate shade. They do best with shade from the hot midday sun with protection from the wind.
They need acid soil but that is no problem in the east where most soils are acid. But it is a good idea to have the soil tested to make sure it is o.k. You can have it tested free of charge or for a small fee at most state universities.
It is a good idea to mix organic matter with the top six inches of soil where azaleas are planted. Peat moss, leaf mold or compost are very good for this purpose.
Be careful not to plant the azalea even an inch deeper than it was growing before. If the roots are too deep into the ground they will not get enough oxygen and the plant will do poorly and eventually die.
They should have the equivalent of one inch of rain every 10 days during the first two years after planting. After they are well established they usually do well with normal rainfall.
A heavy mulch will prevent weeds from growing around the azaleas. Hand pull those that do manage to grow. Do not cultivate around them with a hoe. Azalea roots grow close to the surface and will be damaged if the soil is disturbed.
A condition often called "azalea decline" has been prevalent in some areas for years. Winter injury in the form of bark splitting is one cause but that is usually limited to azaleas that have been planted for less than a year or where the branches do not form a solid canopy, according to Dr. Francis R. Gouin, University of Maryland Ornamental Horticulturist.
It seems to occur during the first two or three freezes in the fall, he says. In unmulched areas the heat radiated from the ground is generally sufficient to reduce the occurrence of bark spliting. In the fall, remove the mulch for a period of time.
"Close examination of many plants brought to me revealed that mice had girdled th stems," he said. Some had symptoms of having been girdled by insects such as weevils.
Repeated applications of acid fertilizers on soils already sufficiently acid have created problems. Making the soil more acid reduces the availability of some plant nutrients while increasing the solubility of other soil elements that are toxic to azaleas.
Over mulching also can cause azalea decline, he says. Yearly applications of two to three inches of mulch appears to suffocate roots of these shallow rooted plants. To survive, the plants must initiate new roots from the stems into the new layer of mulch. It is not uncommon to find two or three different root systems at different levels on the stems of plants that are over-mulched yearly. CAPTION: Illustration, no caption.