Azalea Grow Guide

How to Plant Azaleas

Before you dig a single hole, check the mature height of the azalea variety you're planting. Space multiple plants about half that distance apart. Then follow these steps and you'll set your azalea up for a long, healthy life.

1. Prep the root ball. Thoroughly water the soil in the pot before you start. Lay the pot on its side and slide the root ball out. If it's stuck, run a long-bladed knife around the inside edge to loosen it.
2. Loosen the roots. Gently tease out any roots along the sides and bottom so they aren't encircling the root mass. Only prune roots if they're wound all the way around the pot — shorten those so they'll grow outward once they're in the ground, not continue spiraling.
3. Dig the hole. Make it about twice the diameter of the pot and the same depth. No need to go deeper.
4. Build a center mound. Mound up a small cone of soil in the middle of the hole. Set the root mass on top and spread the roots outward over the mound naturally.
5. Backfill to the right depth. Fill in around the roots until the shrub's stem sits at the same level it was in the original pot. Never plant it lower. Too shallow is better than too deep. You may need to gently pull the plant up as you backfill.
6. Water at the halfway point. Once the hole is half filled, give the roots a deep soak and let it drain completely before continuing.
7. Finish filling and tamp. Adjust the stem depth if needed, fill the hole the rest of the way, and gently firm the soil down with your hands.
8. Build a watering ring. Create a 3 to 6 inch raised dike of soil around the outer edge of the root zone to hold water right where the roots can use it. Then give the whole area a thorough soaking.
9. Mulch the root zone. Spread 3 to 6 inches of organic mulch over the root area and a foot or two beyond. Good options include hay, straw, leaves, pine needles, pine bark, wood chips, or grass clippings.

Two important don'ts:

• Do not use mushroom compost. It contains lime and will raise the soil pH, which azaleas hate.
• Do not fertilize at planting time. Let the roots settle in first.

Azaleas also grow well in containers and raised beds if your native soil isn't quite right for them.

Azalea Soil Guidelines

Azaleas need a soil that is well drained and rich in organic nutrients, although sandy soil that is low in organics is also suitable as long as it gets regular top mulching. Rocky or heavy clay soils are not suitable. If your soil remains soggy for long periods, don’t plant azaleas. To test if it is well drained soil, dig a hole six inches deep and six inches across and fill it with water. If the water has not drained from the hole within three hours, the soil is too poorly drained for azaleas.

Azaleas are acid loving plants, preferring a pH between 4.5 and 6.0. Perform a soil test to check the pH level in your soil levels. If your alkaline soil is calcareous, limey, or has a pH higher than 7, you should forget about growing azaleas in the ground. If your soil pH is between 6.0 and 7.0, you can lower it by adding granular sulfur or iron sulfate to the soil. Work the sulfur into the acid soil about six inches deep. See the accompanying table for amounts to use. If possible, you should get the soil pH corrected at least nine months before planting azalea bushes. 

To lower the pH of a typical loamy soil to 5.5:

How to Care for Azaleas After Planting

Pro Gardener Tip: The most common reason for a newly planted azalea to die is lack of enough water.

Azalea Care After Planting

Watering

How often you water depends on when you planted and what your soil is like:

• Fall or winter planting: Once every one to two weeks is plenty while the plant is dormant.
• Spring or summer planting: Water every day or two for the first three to four months.
• Sandy soil or dry spells: Water every day for the first three to four months. Inconsistent moisture during this window can cause yellow leaves.

Once established after about a year of growth, azaleas can handle moderate dry spells on their own. You generally won't need to supplement unless it hasn't rained in three weeks or more.

Mulching for Azlaeas

Azaleas have shallow root systems, which means the soil around those roots can dry out or overheat quickly. A good layer of mulch is the simplest thing you can do to keep them happy.

• Maintain a 2 to 5 inch layer of organic mulch around the plant at all times.
• Use something that will break down over time, like wood chips, pine bark, pine needles, or peat moss. As it decomposes it feeds the soil.
• Keep mulch a couple inches away from the trunk itself to prevent rot.
• A well-mulched azalea generally won't need any additional fertilizer.

Deadheading Spent Flowers

Removing spent blooms right away redirects the plant's energy from seed production back into healthy growth and next year's flower buds. This matters more for some azaleas than others:

• Evergreen azaleas and rhododendrons: Deadhead as soon as flowering is finished. Skip this step and you'll see noticeably fewer flowers next season.
• Deciduous azaleas: Deadheading is less critical, but it doesn't hurt.

When you deadhead, snap or cut off just the spent flower cluster. Be careful not to remove the new buds already forming at the base of the old bloom cluster. Those are next year's flowers.

Azalea Shrub Pruning

Azaleas are naturally well-shaped shrubs and rarely need pruning. When you do need to trim for size or shape, timing is everything:

• Prune right after flowering, not before. Azaleas start setting next year's flower buds very soon after they finish blooming, and pruning too late means cutting off that display.
• To rejuvenate an old, spindly plant, cut it back by a third or more. Even aggressive cuts will re-sprout reliably.
• With the right pruning over time, you can even train an azalea into a small tree form.

Ongoing Maintenance

Once established, azaleas are genuinely low-maintenance shrubs. Check the soil periodically during hot or dry stretches and water deeply if it's dry. That's really about it. Get the planting right and the mulch down, and these plants will take care of themselves for years.

What’s the difference between an azalea and a rhododendron?

We promise these plants are worth the small effort to keep them alive and flourishing. They will reward you year after year with beautiful azalea blooms. Happy planting!