Rhododendron indicum


Michael's Opinion

Rhododendron indicum is a beautiful showy plant that requires lots of maintenance. This plant can be difficult to grow and has lots of pest issues, although it is tolerant to rabbits. Definitely not recommended for beginners, but to those who have some experience and time to provide the proper care for the plant it can be an attractive addition to the shady area of one's garden.

Botanical Information

FamilyEricaceae
GenusRhododendron
Speciesindicum
CategoryWoody
TypeShrub (evergreen)
OriginRhododendron indicum is native to southern and central Japan. This plant was first brought over to North America in South Carolina.
Ethnobotanical Uses
Disclaimer
Rhododendron indicum is a poisonous plant so it is not used for any edible purposes. This plant has no known medical uses past and present. An extract is taken from the flower and used in some hair conditioners.

Details

USDA Hardiness Zone7 - 8
USDA Hardiness Ref.
Canadian Hardiness Zone6b - 8a
Canada Hardiness Ref.
RHS Hardiness ZoneH4 - H6
RHS Hardiness Ref.
Temperature (°C)(-20) - 20
Temperature (°F)0 - 20
Height0.6 - 0.9 m
Spread0.6 - 0.9 m
GrowthSlow
Flowering PeriodMay

Description and Growing Information

General DescriptionRhododendron indicum is a small, poisonous, slow growing, and dense woody broadleaf evergreen shrub. This plant belongs to the Ericaceae family, and its common name is the Southern Indian Azalea. Rhododendron indicum flowers in the late spring but sometimes will flower a second time in autumn.
ID CharacteristicThe best three ID characteristics to look for when identifying Rhododendron indicum are both leaves and stems; they have small hairs making them almost fuzzy, are a dark green colour on the top of the leaves and a lighter green under the leaves, with large pink/red 4 to 5 petal flowers.
ShapeThe shape of Rhododendron indicum is upright and wide spreading. Proper pruning after flowering will create an even denser shrub.
LandscapeRhododendron indicum is used for many different purposes in the landscape such as specimen planting. The flowers on the plant attract bees and other pollinators to gardens. Rhododendron indicum is typically used in mass planting and as a hedge. This plant is also good for shade gardens as it prefers shaded areas rather than sunny ones.
PropagationRhododendron indicum can be propagated by cuttings, seed, and grafting. Cuttings of stem tips should be taken during the summer and soil should be moist and warm (70-75 degrees F). Rooting takes about 8-12 weeks. When seed propagating, seed should be taken in autumn and sowed in late autumn. Germination takes 2-4 weeks. Seeds should be potted and grown in a greenhouse for the first winter. When propagating by grafting all suckers should be removed so they don’t take over.
CultivationRhododendron indicum prefers moist acidic soil. This plant will not tolerate drought and needs to always have moist, well drained soil. This plant also needs partial shade and not full sun. The pH of the soil should lay between 4.5 and 5.5. Rhododendron indicum likes a more sandy or silty soil. Not wind tolerant and should be planted in a protected area. This plant can also be used for bonsai.
PestsRhododendron indicum has many pest problems and is quite susceptible to diseases. Common pests that affect this plant include aphids, scale, borers, mites, and thrips. Some common diseases that may affect the plant are canker, leaf spot and powdery mildew. Rhododendron indicum gets root rot fairly easily and is something to constantly watch for as it can be detrimental to the plant. Proper care and maintenance of the plant will help to prevent most of these issues.
HabitatRhododendron indicum can be found naturally in rocky ravines and in rocks along rivers in Japan.
Bark/Stem DescriptionYoung stems are smooth and have a reddish-brown colour to them; also covered in small brown hairs. The bark on the plant has a flaky texture.
Flower/Leaf Bud DescriptionFlower buds are found at the end of stems and are scaled. The flower buds are small around 1-3cm in size, and are egg shaped. Buds for flowers and leaves are a light green colour.
Leaf DescriptionLeaves on a Rhododendron indicum are in an alternate arrangement and have a lanceolate shape. Leaves are also slightly toothed with a crenate leaf margin. Leaves have a bright dark green top and a lighter green underside in warmer months and turn red in winter. Petiole and veins on leaves are covered in fine small hairs.
Flower DescriptionThe flowers on Rhododendron indicum are a showy bright pink or red colour. Flowers bloom in late spring and sometimes a second time in mid autumn. These flowers attract many pollinators like bees. These flowers are singular, and it is extremely rare for them to have double. Each flower has 4-5 lobes that are long and create a funnel shaped flower. Flowers are roughly 2cm-5cm in size.
Fruit DescriptionThe fruit on a Rhododendron indicum is 5 valved capsules. The fruit are also hairy. The size of the fruit is roughly 5cm long.
Colour DescriptionColour of the foliage of Rhododendron indicum is a dark green on top of leaves and a lighter green on the under sides through out spring, summer and autumn. During the winter the foliage turns a deep red colour. Bark colour of this plant is a dark reddish brown. The flowers on this plant are most commonly pink or red but they can also be white or lilac.
Texture DescriptionRhododendron indicum is a very fine textured plant in both summer and winter months.

Photographs