How to Grow Azaleas
By: Julie Day
If you live in the South, the spring azalea extravaganza is so bright, it’s almost gaudy. Azaleas are one of my favorite plants – they make fantastic foundation shrubs, the blooms are to die for, and if you plant them carefully, they’ll give you decades of low-maintenance enjoyment.
Here’s what you need to know to grow azaleas in your garden.
Azaleas (Rhododendron sp.) are one of the hallmarks of Southern gardens, with thousands of cultivated hybrids and varieties available. In general, azaleas are divided into two groups:
- Evergreen Azaleas: Native to Asia and wow us with the familiar blooms in shades of white, pink, red, and purple.
- Deciduous Azaleas: Native to North America. While they lose their leaves in the fall, they make up for it with delicate spring blossoms in unusual shades of white, pink, red, and even orange and yellow.
When choosing azaleas for your garden, keep these factors in mind:
- Size: Varieties of azaleas range in size from 12 inches to 12 feet. Choose plants that will fit the space, rather than trying to prune into shape.
- Shape: Evergreen azaleas range from round and compact to sprawling and irregular while deciduous azaleas grow more upright. Make sure you understand the growing habits of your variety.
- Blooming: Azaleas generally bloom in April and May, with the blooms lasting about two weeks. Some varieties even bloom again in the fall. For a longer season of color, choose varieties with different bloom times.
- Climate: Some varieties of azaleas are more cold-tolerant than others. Florist’s azaleas (the ones you might receive as a gift) often don’t tolerate freezing temperatures at all. Make sure the variety is hardy to your climate planting zone. One way to ensure this is to buy azaleas from local growers.
Azalea Growing Conditions
- Planting Zone: Most azaleas are hardy to planting zones 6-9, with a few varieties tolerating colder temperatures up to zone 4. Azaleas do best in spots sheltered from harsh winds.
- Partial Shade: Plant azaleas in dappled sunlight, or in a spot with morning sun and afternoon shade. Azaleas naturally thrive at the edge of light pine woods.
- Acidic Soil: Azaleas prefer soil with a pH of 5 to 6.5.
- Good Drainage: Azaleas hate to be soggy, so proper planting is important. Loose soil that is rich in organic matter will provide the best drainage (and also eliminate the need for fertilizer).
How to Plant Azaleas
Fall is a great time to plant azaleas, although you can generally plant them any time during the growing season. When planting azaleas, follow these tips:
- Choose the Right Spot: Plant in an area with loose, rich soil. If you are creating a new planting bed for your azaleas, till and improve the soil at least 18” deep.
- Drainage is Key: Poor drainage is a surefire way to kill an azalea, since they have pretty shallow roots that shouldn’t be smothered. In heavy clay soil, plant azaleas with the root ball an inch or two above the soil level. If you are amending the soil in your planting bed, add in plenty of coarse organic matter to keep the soil loose.
- Mulch Around Plants: Mulch holds in moisture and helps with cold tolerance, but a couple of inches is plenty – again, you don’t want to smother the roots. Leave a few inches of space around the stem.
For more detailed planting information, check out our article on How To Plant Container-Grown Shrubs.
How to Take Care of Azaleas
If properly planted, azaleas are low-maintenance plants. Follow these tips:
- Pruning: Azaleas need little pruning, but you can shape up your azaleas right after they bloom. Remove a few of the spindliest branches, and pinch back the tips of the other branches to encourage fullness. This light annual TLC should keep your azaleas in good shape. By midsummer, the plants have already set next year’s flower buds, so avoid late-season pruning.
- Watering: Your azaleas might need some supplemental irrigation during droughts. Water deeply, rather than frequently, and keep them mulched to hold in moisture. To ward off cold damage, water azaleas thoroughly before the first hard freeze.
- Feeding: In good soil, with a nice organic mulch, azaleas don’t really need supplemental fertilizer. If you do feed your azaleas, choose a fertilizer specifically for acid-loving plants (it will usually be labeled for azaleas and rhododendrons), and apply fertilizer right after they finish blooming.
- Problems: Most azalea problems, including lack of blooming, come from poor soil, cold damage, improper watering, or improper pruning. Diseases and pests are less common, and most problems can be discovered and treated in time for the plant to recover.
- How to Plant Azalea Shrubs in Your Yard (video)
- Growing Azaleas and Rhododendrons (University of Missouri)
- Azalea Society of America