Light
While this shrub will survive in a location with nearly full shade, flowering will be better in full sun to partial shade.
Soil
The ground should be kept evenly moist, but the soil should drain well. Japanese andromeda does not thrive in soggy soil.
Water
Japanese Andromeda has average water needs and does not tolerate drought well. Water if the first 3 inches of the soil feels dry.
Temperature and Humidity
This plant thrives in a moderate climate, where the temperatures don’t get scorching hot. It tolerates a wide variety of humidity levels.
Fertilizer
Feed Japanese andromeda with a fertilizer meant for acid-loving shrubs. So if you are already fertilizing your azaleas, for example, you can use the same fertilizer for your Japanese andromeda.
Types of Japanese Andromeda
Beyond the species plant, cultivars have been developed that have become quite popular. The new spring leaves of even the species plant have a reddish-bronze color, but, on a number of the cultivars, these same leaves offer a more striking red color. Notable cultivars include:
‘Compacta’: This is a good choice if you need a shorter plant, as its mature height is just 4 feet. ‘Forest Flame’: New spring leaves start out an intense red, then fade to a pink that is still quite attractive. ‘Mountain Fire’: Orange mixes with the red on the young leaves of this cultivar. ‘Red Mill’: This is one of the best cultivars if you seek bright red color on the new foliage. ‘Valley Rose’: Grow ‘Valley Rose’ if you want a Japanese andromeda that bears light pink flowers. ‘Variegata’: One of the cultivars with two-toned leaves, the foliage of ‘Variegata’ is green in the middle, but the edge of the leaf is white.
Pruning
This plant has a naturally attractive shape and will often grow neatly with no pruning. However, cut off dead, dying, or diseased branches, and tidy up the foliage occasionally.
Propagating Japanese Andromeda
Though Japanese andromeda can be grown from seed, it takes a long time for the seeds to germinate and grow. Therefore, most choose to propagate the plant from cuttings:
Potting and Repotting Japanese Andromeda
When planting Japanese andromeda in a pot, select one about the same size as the nursery pot it came in and make sure it has large drain holes, as Japanese andromeda does not like wet soil. Fill the pot with well-draining potting mix and tamp the soil down around it with your hand to remove any trapped air. Water the plant immediately afterwards. When the root system has filled the pot (an indicator is when water rushes right through the pot, or you see roots growing out of the drain holes), it is time to transplant it to a larger pot, one size up. Do this in the spring or fall and work some compost into the potting mix.
Overwintering
Japanese andromeda is winter hardy to USDA zone 5 and needs no winter protection when grown in garden soil but the roots of container plants should be protected from cold, drying winter winds by wrapping burlap and a layer of bubble wrap around the container, or by placing it in an insulating silo.
Common Pests and Plant Diseases
Fungal diseases are a common plague for Japanese andromeda. To avoid this, ensure good air circulation around the plant and use a fungicide when appropriate. The andromeda lacebug often attacks this particular plant, hence the name. To prevent it, keep your plant in full sun, apply horticultural oil to the undersides of the leaves, and use pesticides if necessary.
How to Get Japanese Andromeda to Bloom
Failure to bloom is often caused by lack of sunlight. While the plant tolerates partial shade, too much shade is detrimental to its bloom.
