An Azalea plant is the national flower of Nepal, and is part of an ancient group of plants dating back million of years. They are related to rhododendrons and blueberries and are descendents of Asian shrubs. Azaleas can also be used as a centerpiece for weddings or to replace expensive cut flower arrangements in your home or office. Azaleas have delicate, funnel shaped, lipped flowers that can be red, pink, white, yellow, purple and even bi-color. These plants are considered poisonous and should be kept away from pets and children. Read more about common houseplants that can be dangerous in my book Don’t Feed Me to Your Cat: A Guide to Poisonous Houseplants. Azalea plants have terminal blooms which means the entire plant flowers at one time making a beautiful display. Since florist azaleas are different than specially grown outdoor azaleas, indoor azalea plants that you receive as a gift rarely do well planted outside in your garden.
Plant Care
Light
Azalea plants require bright indirect light while blooming, but no direct sun. If there is not enough light, the flower buds on an azalea plant won’t open.
Water
Allow the top 2″-3″ of soil to dry out before watering. Azaleas are acid loving plants; if your water is alkaline add one tablespoon of vinegar to each gallon of water. You can also water azaleas with leftover tea. Large numbers of leaves drop off if the soil is too wet or too dry.
Fertilizer
Fertilize monthly with an acidic fertilizer diluted to 1/3 the recommended strength. Never fertilize your azalea plant when it is in bloom.
Temperature
Azalea plants thrive and their flowers last longer when the temperature is 50°-60°F (10°-15.6°C) at night and 60°-70°F (15.6°-21.1°C)F during the day. Temperatures over 80°F (26.7°C) cause leaf drop and flowers to quickly fade.
Humidity
Azalea plants do well in normal to high humidity.
Flowering
When purchasing an azalea for yourself or as a gift, buy one that has buds barely showing a little color as well as open flowers. Once brought home, place your new azalea in a bright, cool location, away from heaters, air conditioners, and direct sun. This should keep the plant in bloom for quite a while.
Pests
Azalea plants are susceptible to spider mites, scale, and nematodes.
Diseases
Azalea gall occurs in early spring. New leaves curl, become pale, turn brown and die. Petal blight, powdery mildew, and rust are all types of fungus that can infect azaleas. Remove diseased leaves as soon as they appear and spray with a fungicide.
Soil
Use a rich acidic planting mixture that drains well.
Pot Size
Azaleas can be found in 4″, 6″, and 8″ pots.
Pruning
Remove dead flowers as soon as they appear and prune bare branches.
Propagation
Azalea plants are propagated by stem cuttings, grafts, and tissue culture, but it is a difficult process. I recommend leaving it to the professionals.
Resting Period
After your azalea has finished blooming and you’ve pruned it, move the plant to a cool room with less light. Keep the soil a little drier than usual and fertilize monthly. After several months, when buds start to appear, move your azalea back into bright indirect light.
Special Occasion
Azaleas are lovely flowering plants that make a perfect gift for Mother’s Day, Valentine’s Day, anniversaries, birthdays, and as a get well present.
Poisonous Plant Info
All parts of an Azalea contain a substance called grayanotoxin which makes the plant very poisonous with a #4 toxicity level. Keep azalea plants away from children and pets.
FAQ
Leaves fall off an azalea plant for several reasons: The temperature is too hot or the humidity too low. The soil is too wet or the soil is too dry. The azalea plant is in a draft, near a cold door, or in front of a drafty window.
You can get an azalea to bloom again indoors but it’s not easy. Azalea plants require about 6 weeks of very cool 40°-50°F(4.4°-10°C) nighttime temperatures for their buds to set. High humidity is also necessary. Once the buds develop, move your plant to a warmer, brighter location. Indoor azalea plants may re-bloom once a year if you’re lucky.
Here are a few tips that might help the flowers on your azalea plants last a little longer. When you buy an azalea, select a plant that has only a few open flowers and mostly buds. The buds should be showing a little color. At home, place your new azalea in a bright, cool location, away from heaters, air conditioners, and direct sun. This should keep the plant in bloom for at least a few weeks.
Your azalea plant has probably gotten too dry and the soil has contracted so much that the water runs right through without being absorbed. Place the entire plant, pot and all, in a bucket or sink full of water and hold it there until the air bubbles stop coming out of the soil. Once all of the air has escaped and the soil has expanded, your azalea plant should be able to absorb water normally again.