A spectacular show of blooms in the spring make azaleas among the most popular garden shrubs. Botanists classify azaleas within the rhododendron family of plants. The term azalea is used for the smaller species of rhododendrons that lose their leaves each year. They are native to areas of Tibet, western and central China, the Philippines and Malaysia. Azaleas prefer a moist, humid climate where water is easily available.
Azaleas have funnel-shaped flowers with five stamens in the center. They bloom in a range and variation of colors from white to pinks to yellow. Flowers are single- or double-petaled, with ruffled or smooth edges. Azaleas are often placed in the landscape near fountains, steps and decks to soften architectural features. They also do well when planted in raised beds where the soil can be amended easily.
Good drainage is essential for azaleas. They perform poorly in heavy clay soil that is sodden. This can be tested by digging a 1 foot hole in the ground, filling it with water and watching how long it takes to drain. If the water is not completely drained within two hours, the soil needs to be amended. Composted organic matter improves drainage.
Roots and Water
Azaleas have a shallow root system that cannot reach deeply into the soil for water. They prefer a regular schedule of watering so the roots do not become dried out. Moisture evaporates easily in the upper 3 to 4 inches of soil, especially in dry climates. They grow well when given 1 inch of water once a week.
Drooping, wilting leaves develop if soil is not well-drained and the root system has become waterlogged. Water-soaked roots become devoid of oxygen and cannot take up water into the leaves. The remedy is to dig into the soil and provide drainage through channels or holes. The soil-drainage problem can then be corrected by adding compost, such as dry leaves or bark.
A high level of organic matter in soil ensures good drainage and fewer watering problems for azaleas. They like soil that is slightly acidic. Coffee grounds, pine needles, dry leaves and vegetable scraps in homemade compost raise the acid level. If soil is very heavy, use ground pine bark or oak leaf mold as amendments before planting. They can also be used as mulch, which is absorbed into the soil to increase acidity.