Azalea Time in the Arboretum
It’s Azalea time at the Outer Banks Arboretum & Teaching Garden. We encourage you to take stroll and an enjoy this beautiful sight.
Azaleas are among the most popular flowering shrubs grown. With proper site selection and planting methods they can do very well here on the Outer Banks.
For more information, check out this video presentation by the Dare County Extension Master Gardeners:
Azaleas prefer cool, partially shaded sites, such as the filtered shade of pine trees. Flowers last longer when plants are partially shaded. Although some varieties tolerate sun better than others, they all prefer an area that is not exposed to long periods of hot, full sun and drying winds. Do not plant azaleas in heavy shade, as poor flowering and weak growth may result. Avoid planting under hardwoods, since they must then compete with the trees for nutrients and water.
Azaleas grow best in slightly acidic (4.5 to 6.0 pH), well-drained, organic soils. Before planting, test the soil in the areas you may want to plant your azaleas then adjust the planting site according to the results. Soil test kits can be picked up at the N.C. Cooperative Extension office in Dare County. Well-drained soil is very important to avoid damage to the roots. If the area is not well drained, add composted pine bark to as large an area as possible, and plant the root ball slightly higher than ground level.
A 2- to 3-inch layer of organic mulch is very important. It conserves soil moisture, maintains soil temperature and helps discourage weeds. Pine straw, composted pine bark and leaves work very well as mulch, enriching the soil with organic matter as they decompose. Keep the mulch a couple of inches away from the main stem to keep the bark dry and extend it beyond the outermost branches.
Azaleas require irrigation during dry periods. This is especially true of those planted in the spring. Azaleas planted in warm weather in sandy soils may require watering of the root mass twice a week during the first year. Overhead irrigation such as sprinklers may promote disease.
Azaleas have low nutritional requirements compared to other shrubs. A soil amended with organic matter prior to planting followed by a mulch of organic material will usually provide enough nutrients for adequate growth. Before fertilizing, have a specific reason for doing so, such as increasing growth rate or correcting a nutrient deficiency. Symptoms of a nutrient deficiency may include stunted growth, smaller than normal leaves, light green to yellowish leaf color and
early leaf drop. Be aware that these same symptoms can be caused by other problems such as heavily compacted soil; stresses from insects, disease organisms and weeds; and excessively wet or dry soil. Fertilization will not correct those problems, so be certain that you know the cause of the symptoms and treat them appropriately.
Thinning removes branches back to the main trunk or another branch. This method is used to remove leggy branches that extend beyond the canopy of the plant, remove damaged or diseased wood, or reduce the size of the plant. Thinning allows light to penetrate the shrub, encouraging growth on interior branches. You can thin at any time of the year without causing a significant impact on flowering, growth or cold hardiness of the plant. However, to reduce the impact on flowers the following year, prune just after flowering in the spring. Heading refers to the cutting back of a branch, not necessarily to a side branch. This method is used to reduce the size of a plant, create a hedge or to renew old overgrown plants. Renew overgrown plants by cutting them back to within 6 to 12 inches of ground-level. This practice results in abundant new growth by midsummer.
To request more information or a copy of the Azalea handout, please email the Dare County Master Gardener Volunteers at firstname.lastname@example.org.