Azaleas grow best in mild, humid climates and for decades they have thrived in the gardens and parks of northeast OK. They have been a constant mainstay of gardens because of their exuberant spring flower show and the beautiful green leaves that persist until hard freezes arrive.
The flowers are shaped in funnel, bell or tubular forms and are often fragrant. For best flowering, they need regular, early morning moisture, particularly during hot and dry weather.
Changes in weather patterns, specifically periods of drought, will stress Azaleas. If branches look
like they are wilting, the shrub may need more morning water.
Their shallow root system demands damp but never water-logged soil. A 3-inch deep mulch, added annually will protect the roots from drying out. Azaleas are one of the few plants that can thrive close to lawn sprinklers.
Azaleas need to be protected from full sun so they are usually planted under trees. Harsh south and west winds also dry out azaleas so it is recommended that they are planted on the east and north sides of buildings and slopes.
Strong, harsh wind also causes leaf scorch and bark splitting so plant them next to buildings and on slopes, avoiding building corners. Planting evergreen shrubs such as pine, spruce and juniper the south and west of Azaleas will protect them and provide a background contrast for the flowers.
It is a good idea to plant Azaleas in groups away from shallow rooted trees such as maple, ash and elm that steal the water and food provided for the Azaleas.
Muskogee Azalea grower, Ray Wright at Green Country Landscaping (918-261-0854) said, “You need a $5 hole for a $3 Azalea. They need soil that has been amended to have low pH of 5.0 to 5.5. The best way to plant them is to dig a hole 4-feet wide and 18-inches deep. Mix that soil with baled Canadian peat moss and plant the shrub high so water drains and sinks down.”
Wright also said that an acid mulch of ground pine bark, pecan shells, pine needles or cedar mulch will help maintain the acidic level the roots need.
Fertilize them now, in the spring, at half-strength and then at full-strength after the flowers fade.
Look for a product that is formulated for acid-loving plants with iron and Sulphur. Slow release products work well.
It is rare that they need to be pruned but if they need shaping, it is best to do it immediately after spring flowering and never after the summer heat hits after July 1.
Azalea problems can come from a variety of insects and diseases. Azalea Stem Borers, Oberea myops and Rhododendron Borer, Synanthedon rhododendri, can attack, killing portions of a plant, giving the impression that it is dying.
Plants attacked by borers can be saved by cutting off the area where the borer has caused damage. The shrub will regenerate from the roots. The shrub will die only if the borer is in the primary trunk near the root.
Old plants with weak immune systems can be attacked by soil-borne fungus, Armallaria which occurs naturally where oak trees grow and Phomopsis rhododendri. Remove any dead branches with loppers dipped in 10-percent bleach solution (1-part bleach to 9 parts water) between every cut made.
Plants can be rejuvenated and propagated. Peg a low branch to the ground in a shallow trench and anchor it. A new plant will root in the trench and grow from the leaf stem left out of the trench.
The thick mulch should eliminate any need to weed under Azaleas and you should never cultivate around their shallow roots with hoes or power equipment such as a lawn edger or mower.