AZALEAS

Azaleas have become one of the most popular landscape shrubs grown in the Tulsa area. Azaleas are members of the genus Rhododendron. In common usage, the term “rhododendron” refers to the plants with larger, leathery leaves while “azalea” refers to those with smaller, thinner leaves.

The first requirement needed for azaleas is SHADE! If you don’t have shade in your yard, forget about azaleas. Hundreds of varieties of azaleas are available and choosing can sometimes be overwhelming. For help in choosing just the right azalea for your location visit with one of our nursery specialists. Remember, trying to grow an azalea in the wrong location or under the wrong conditions will bring about disappointment and poor results.

Azaleas grow best when planted in acid soils with a Ph of 4.0 to 6.0. We recommend adding peat moss to your soil to increase acidity. A loose soil rich in well-composted organic matter is ideal, and good drainage is a must. If drainage is a problem, a raised bed may be the solution for you. Azaleas perform best with morning sun only. Sun after about 12 noon will probably mean the end for most azaleas. Dense shade is also not recommended because the azalea will most likely not get enough sun to produce good blooming. Don’t place the bed close to shallow-rooted trees such as maple, ash or elm. Feeder roots from these trees will rapidly move into improved soil and compete for water and plant food.

Proper placement is not enough. Azaleas must have soil that is prepared carefully and thoroughly. Don’t expect good results from plants set in existing soil in most areas. Roots of azaleas are very delicate and unable to penetrate heavy or rocky soils.

Because the delicate roots of azaleas are easily destroyed, excellent drainage is important. To test drainage, dig a hole 6” deep in the bed and fill it with water. If the water has not drained in four hours you have a drainage problem that will need to be addressed before planting azaleas.

Proper spacing between plants reduces competition for water and nutrients. Azaleas should be placed at least 2-3’ apart. For best results, dig the planting hole twice the size of the container but no deeper than it is in the container. Amend your soil from the planting hole with a 75% peat & soil mixture. Wetting the peat makes it easier to work with. Good soil preparation allows rapid root extension and better plant growth.

Azaleas are surface-rooting plants, therefore the root ball should be opened and spread slightly at the bottom and left exposed at the top. After setting your azalea begin backfilling with your peat & soil mixture, watering as you go to reduce air pockets. The peat & soil mixture is then mounded around the root ball. Finish off with a good 2-3” layer of shredded mulch.

Adequate soil moisture is critical for the first growing season when roots are becoming established. Dry or stressed plants are more susceptible to insects, disease and other injury. A newly planted azalea requires special attention, because the newly mixed planting medium (peat & soil) will dry out more quickly than the surrounding soil. Check the root ball moisture by inserting your finger in the soil which should feel damp to the touch. A slow, thorough watering from the bottom is far better than a sprinkler.

Azaleas require little more when the soil has been prepared properly. However, we do recommend fertilizing for next years blooms AFTER your azalea has finished blooming in the spring. This can be done easily with a granular slow-release azalea fertilizer. We do not recommend fertilizing after August first.

Azaleas are called continuous growers because new shoots emerge from branch tips and grow all season. It is important to prune young plants after flowering to promote lateral branching. To maintain a loose, open shrub, some larger branches can be cut out from inside older plants, which allows light and air to penetrate the interior. Pruning and fertilizing may be done at the same time and we recommend always BEFORE August first.

Lace bugs and spider mites can damage azaleas extensively if not stopped. A lacebug infestation can be identified by white mottling of the leaves, usually on the underside. Isotox® or Orthene® are both effective controls. Spider mites are identified as black specks or webbing on the plant. If webbing is appearing you already have a significant problem and you need to take action! Kelthane® or Orthene® are both effective for mite problems.

Azaleas in Oklahoma are not troubled by disease. Keeping your beds clean and pruning implements sterilized helps insure disease free azaleas. Iron chlorosis is sometimes mistaken for disease. If leaves turn yellow in sections between the veins, but the veins remain green, iron deficiency is probably the cause. This can easily be controlled with an application of iron sulfate or chelated iron. Always follow manufacturers recommendation.

The two worst enemies of azaleas are sun and cold wind. If the proper locations are chosen, and mulch is applied little or no winter protection is needed. Screens or burlap may be needed to provide a windbreak. Don’t be alarmed if leaves curl and droop on cold days, this is normal.