How to Care for Azaleas
Azaleas thrive in well-draining acidic soil. Before planting azaleas in your garden, ensure the soil has been treated with compost. When done planting, consider adding a top layer of pine straw or mulch to further enrich the soil and keep moisture levels high.
How to Repot Azaleas
Examine your potted azaleas about every six months to see if it has begun outgrowing the pot. Look for the fine roots. If they have started to circle at the bottom of the pot, it’s time to repot.
- Select a pot 2 to 4 inches wider than the previous pot, ensuring that the pot has at least one drainage hole. If reusing a pot from a previous plant, clean it with soap and warm water.
- Add new potting mix to the bottom of the new pot so that the old soil hits about ½ inch below the rim of the pot when the root ball is placed on top of the new soil. Adding too much soil on top of the crown of the plant can also cause rot. Add more soil to the edges. Press soil firmly around the roots with your fingers to ensure good rooting.
- Tap pot on the counter or ground to ensure proper settling of soil and to remove air pockets. Add more potting soil as necessary, remembering to keep the soil about ½ in away from the top of the pot.
- Water the azalea until the soil is moist but not soggy. Monitor moisture levels closely. Avoid letting the soil dry out or letting it get too moist.
- Fertilize azaleas during the growing season with a low-nitrogen additive for acid-loving plants such as azaleas.
How to Grow From a Cutting
Not all plants can be propagated from cuttings, but azaleas are one of those plants that can!
- Take a cutting from a section of new growth from your azalea plant. Look for wood that is somewhat soft but not brittle.
- Cut a piece that is between two to five inches long, during a cool time of the day or after a good watering. It’s best to cut the plant when it is less likely to be stressed.
- Strip all foliage from the branch except for the top bunch of leaves. Make sure to keep the bark in tact, except for the bottom half inch of the branch, which you should scrape off gently with a clean knife or your fingernail.
- Dip the wounded portion into a liquid hormone solution for up to 5 seconds, and shake up any excess.
- Plant the branch in a 50/50 peat and perlite-rooting medium that is 4 to 6 inches deep. Keep soil moisten, and not packed down to help promote drainage and aeration. Feel free plant multiple branches in the same container.
- Water the branches well and be patient. Your cuttings should take root in about 4 to 8 weeks. Check for progress by gently tugging on the emerging cutting; if you feel resistance the cutting is taking root.
- Transplant the rooted cutting to another pot, and keep it away from freezing temperatures in a greenhouse or cold frame for at least one year, suggests the Azalea Society of America.
General Care Tips
Outdoor azaleas thrive in USDA plant hardiness zones 5 through 9, notes Gardening Know How. Azaleas thrive when protected by shade in the afternoon and exposed to light in the morning when temperatures are cooler. Avoid selecting locations that will receive intense heat, direct light or total shade for the entire day.
Deadhead your azalea frequently to keep your plant looking its best. Removing spent blooms encourages new growth and keeps the plant from looking raggedy.
How to Trim
When you trim your azalea will depend upon the type you have. Some azaleas bloom on old wood (last years growth) whereas other bloom on new wood (growth from the current year).
Although azaleas are a shrub, don't trim them in a formal manner. Straight edges or formal shapes often results in “spotty flowering and splotchy growth” notes Gardening Know How. Trim branches that stick out outside of the natural shape. Don’t worry about finding a “connecting branch” or elbow area of the branch, azaleas are hearty and will grow back on new growth. Cut branches back one-third to one-half of the length.
Always ensure you use sterilized clippers when trimming plants to avoid spreading disease.
Although azaleas are generally easy to care for, and don’t normally have issues with pests or diseases, they can sometimes suffer from root-rot, blight, or pests.
Root rot occurs when the plant has been watered too much or too often. Planting azaleas in a location with adequate sun, good drainage, and conserving water, and applying a layer of mulch will help reduce the likelihood of root rot.
Gardening Know How: Good Azalea Care
SF Gate: How to Pot an Azalea
Azalea Society of America: Propagation
Questions & Answers
My outside azaleas are planted in groupings and had done quite well until about three years ago. Slowly, plant by plant, they began to yellow and after a couple of years died. The leaves get smaller with age, and they yellow and produce fewer or no flowers. What is the problem?
If you've already ruled out root rot, the most likely answer is a nematode infection. Consider collecting a soil sample from the affected area, and sending it to a local cooperative extension service for evaluation.
Visit http://npic.orst.edu/pest/countyext.htm for the contact info for the nearest local assistance.