Origin: Japan, China, Korea, Taiwan, North America, Eastern Europe
Growth season: Winter to spring
Flowers: White, pink, lilac, purple, orange, red (depending on species)
Location: Indoors (filtered sunlight, or two hours direct sun) and outdoors (shade)
Minimum temperature: 5° C
One of the most beautiful bonsai options, azaleas are valued by plant lovers worldwide for their gorgeous flowers. With a range of colours and shapes, azaleas can be cultivated into the perfect display piece for your home.
Azaleas are an evergreen shrub from the rhododendron family, with the Satsuki azalea (Rhododendron indicum) and Kurume azalea (Rhododendron kiusianum and Rhododendron kaempferi) being the most commonly used for bonsais. Our care instructions apply for all sorts of azaleas, but if you have any specific questions, make sure you reach out to one of our specialists.
Caring for an Azalea Bonsai
Azaleas thrive with lots of natural light, but cannot take too much sun. Their shallow roots can become damaged if exposed to constant heat. If you are keeping your bonsai outside, make sure that you place it in the shade or an alfresco with filtered light.
If inside, ensure that your azalea receives plenty of filtered sunlight or at least two hours of direct sun a day. They prefer the morning sun, so take this into consideration when choosing a spot for your bonsai.
Azaleas like to be wet at all times. If the soil is dry to the touch, make sure to apply a bit of water — never let the soil completely dry out. For new owners, you may want to invest in a moisture meter to help you determine the right watering schedule for your bonsai.
However, you must be careful of overwatering, as this can lead to root rot. Good drainage is a must when it comes to choosing a pot for your azalea, allowing your bonsai to take as much water as it needs without drowning. You must also consider what you use to water your plant, as hard tap water is not suitable for azaleas due to lime content. There are a few options at your disposal: leave out a few buckets and collect rainwater, mix small amounts of rainwater with your tap water or filter your tap water.
A humidity tray may also be a good idea, especially if your plant is indoors and in the winter. Place a shallow tray of stones and water (making sure the water doesn’t touch the pot) beneath the azalea. Misting can also be a good alternative to keep the air nice and moist for your bonsai.
Azaleas like more acidic soil (pH 5–6), so avoid applying lime or fresh manures; aged cow manure, however, can be helpful. A special azalea or rhododendron fertiliser tailored to the azalea’s unique nutritional needs is the best way to go. A layer of organic mulch should also be used to protect the roots and maintain the moisture inside the soil.
Start feeding your azaleas in August, just before spring, and continue until early January, when the next year’s buds have begun to set. Mulching should be done in late spring to prepare the azalea for summer.
After the tree finishes flowering, make sure you remove all the dead blooms at their base. This will ensure that seed pods do not form and will help to encourage healthy flowers next year. The buds begin to grow in the summer, so make sure that you prune early enough; otherwise, the branches and flowers will suffer in the next growing season.
Azaleas are generally bottom-heavy, meaning you should prune more towards the base of the tree. The plant responds well to pruning; only leave a few of the newer shoots, where you want to encourage branches to grow. Using this tactic, azaleas can be trained in all sorts of shapes and aesthetics.
Azalea branches are very brittle, meaning they can be difficult to wire. Only choose the most flexible branches and use aluminium wire. Typically, it is better (and just as effective) to use pruning to shape and style your azalea.
Your azalea should be repotted every couple of years, ideally at the start of spring or right after it finishes flowering. Younger plants may require annual repotting, as they may grow faster and outgrow their homes sooner.
While repotting, you will need to prune the plant’s roots. Up to a third of the roots can be removed; the heaviest roots should be cut, leaving the finer ones to sustain the plant.
When choosing a new pot for your azalea, deeper is always better. This allows for better drainage and will better accomodate the plant’s needs. You should also select a porous potting mix for the best results.
Softwood cuttings should be taken from the end of December to early February. These can be anywhere from 5 to 10 cm long, and should only have leaves left — no flowers.
Place your cuttings together in a small pot with a sandy soil mixture and keep them damp. Filtered sunlight is great for growth, but make sure they aren’t exposed to too much direct sun.
Unfortunately, pests love azaleas just as much as humans do. These bonsais are susceptible to red spiders and lace bugs, among others. In mid-September, spray both sides of the azalea’s leaves with a suitable pesticide; continue this once a month until January. This prevents the pests from taking up shop and will make your life easier in the long run.
The flowers of the azalea can also suffer from a fungal disease known as petal blight, which wilts the flowers and causes them to become soft and mushy. The fungus attacks the base of the flower, meaning it is important to remove the entire flower and put it in the rubbish (not your compost). To prevent this, spray with a fungicide when the buds start to change colour and avoid watering the flowers directly; instead, wet the soil.
Lastly, like humans, your azalea can suffer from iron or magnesium deficiencies. If your leaves turn yellow with prominent green veins, make sure that you supplement your plant with the correct nutrients. Mix iron sulphate and magnesium sulphate (Epsom salts) with water and apply to both the plant and the soil.
Need more advice for your azalea bonsai? Get in touch with us today!