The Japanese azalea (Rhododendron japonicum, also known as the 'rose tree') is a very robust, hardy plant. Since the extremely richly flowering shrub also prefers shady locations, it is wonderfully suitable for many gardens with trees or many trees.
Is the Japanese azalea hardy?
The Japanese azalea (Rhododendron japonicum) is hardy and can usually do without winter protection, except for very young plants, extreme cold periods or frost. For potted azaleas, the root area should be protected from frost.
Garden azalea vs. indoor azalea
But be careful when buying, because if it says 'azalea' on the label, it doesn't necessarily mean a Japanese azalea. A rough distinction is made between hardy garden azaleas (the Japanese azalea) and non-hardy indoor azaleas. The latter come from the subtropics and tropics of Southeast Asia and would not survive a German winter. They are purely houseplants. Be sure to pay attention to the following designations:
- Japanese Azalea
- Garden Azalea
- Rhododendron japonicum
- Azalea mollis
You can access it without any worries because it is always the winter-hardy version. However, if only 'Azalea' is on the label, it is usually an indoor azalea.
Japanese azalea - winter protection necessary or not?
Japanese azaleas usually do not need winter protection unless
- These are very young plants.
- the winter is very cold, but without snow (cold frost).
- the ground is frozen (roots can no longer absorb water).
In these cases you can cover the root area with reed mats or similar. You should also definitely use frost-free days to water the plant. Prolonged ground frost sometimes means that the shallow-rooted plant can no longer absorb moisture and simply dries up.
Overwintering potted azalea properly
Since the Japanese azalea rarely grows higher than two meters and can be kept under control by pruning, it is often cultivated in pots. Of course, potted azaleas are also hardy, but different rules apply to them when it comes to overwintering. Since the roots have no resistance to the frosty outside temperatures due to the planter and the small amount of soil, you must provide the necessary protection. To do this, place the container on a base made of Styrofoam or wood and wrap the container with reed mats or fleece. A protective location near a heat-emitting wall is also useful.
Tip
Before spring shoots, check the plants for any frost damage - this particularly affects the evergreen varieties of Japanese azalea. Don't be surprised by curled leaves, this causes the plant to protect itself from excessive moisture loss through evaporation.
