Maintenance Landscaping Design

Rhododendron arboreum is a plant that is native to Nepal and India. It is an evergreen shrub or small tree that can grow to a height of 15-20 m. The leaves are dark green and leathery, and the flowers are white or pink. The fruit is a red drupe.

Alternative name

• Tree Rhododendron
  
• Rosebay Rhododendron
  
• Himalayan Rhododendron
  
• Indian Rhododendron
  
• Tibetan Rhododendron

Things to Know

• Rhododendron arboreum is a member of the Ericaceae family.
  
• It is an evergreen shrub or small tree that can reach a height of 15 metres.
  
• The leaves are glossy and dark green in colour, and measure 7-14 cm in length.
  
• The flowers are white or pink in colour, and bloom in clusters of 3-20.
  
• The flowering period typically lasts from late winter to early spring.
  
• The fruit is a small capsule, which contains numerous tiny seeds.
  
• Rhododendron arboreum is native to the Himalayan region.
  
• It is found in Nepal, Bhutan, India, Pakistan, and China.
  
• Rhododendron arboreum is used as an ornamental plant in gardens and parks.
  
• It is also used in traditional medicine for the treatment of various ailments.

Growing Steps

1. For rhododendron arboreum, first step is to choose a location. Select a spot that has well-drained, acidic soil and is in partial to full sun.
   
2. Next, clear the area of any weeds or debris.
   
3. Next, dig a hole that is twice the width and depth of the plant’s root ball.
   
4. Place the plant in the hole and backfill with soil, tamping down gently as you go.
   
5. Water the plant deeply immediately after planting.
   
6. Apply a 2-3 inch layer of mulch around the plant, being sure to keep it away from the plant’s stem.
   
7. Water the plant regularly, especially during the first growing season.
   
8. Fertilize the plant in early spring and again in mid-summer with an acid-loving plant fertilizer.
   
9. Prune the plant as needed to shape and control growth.
   
10. Enjoy your beautiful rhododendron arboreum!

Related plant:
Rhododendron Scarlet Wonder

The Soil

About soil condition, Rhododendron arboreum prefers well-drained, acidic soil, high in organic matter. If the soil is too alkaline, the plant will suffer from nutrient deficiencies. The ideal soil pH is between 5.5 and 6.5.

Light requirement

Not too different with other rhododendrons, rhododendron arboreum requires little to no direct sunlight to thrive. In fact, too much direct sunlight can actually damage the plant. Instead, this type of rhododendron prefers filtered sunlight or dappled sunlight.

Good Temperature

The temperature conditions that are ideal for Rhododendron arboreum are cool to cold temperatures. They prefer temperatures that are between 10 and 15 degrees Celsius. However, they can also tolerate temperatures as low as -5 degrees Celsius.

Ideal Humidity

Ideal humidity condition for this plant is around 50-60% and it don't like to be in either too dry or too wet soil. If the humidity is too low, the plant will suffer from dehydration and if it's too high, the plant may develop fungal infections.

Fertilizing

Mentioning fertilizer, this kind of plant need little amount of fertilizer and too much fertilizer will make the leaves become yellow and then drop off. With regard to the root, it is necessary to water it regularly and do not let the root become dry because it will cause the leaves to wilt and fall off.

Plant Pruning

Pruning rhododendron arboreum is best done in the late winter or early spring, before new growth begins. The plant can be pruned quite aggressively, as it will quickly recover and fill in any bare areas. When pruning, be sure to remove any dead or damaged wood, as well as any crossed or rubbing branches.

Plant Propagation

Propagation of rhododendron arboreum is typically done via rooting of stem cuttings. Cuttings should be taken from firm, healthy stems that are about 6-8 inches long. The cuttings should be taken just below a leaf node and then be placed in a well-draining propagation mix. Once the cuttings are in the propagation mix, they should be watered well and then placed in a warm, humid environment. A plastic bag placed over the top of the pot can help to create the desired environment. After a few weeks, the cuttings should develop roots and can then be transplanted into individual pots.

Plant Growth

Usually, the plant growth rate is between 10 and 20cm per annum. However, it has been recorded that some individual specimens have attained a growth rate of up to 50cm per annum. The main drivers of the rhododendron arboreum growth rate are temperature and moisture.

Common Problems

Common problems for this kind of plant are typically insect related. These problems include root rot, leaf spot, bud blast, and stem dieback. Often times, proper cultural practices can help to manage these problems. For example, avoiding overwatering, planting in well-drained soils, and removing infected plant parts can help to control root rot. Managing leaf spot may require the use of fungicides. And, finally, pruning out dead or infected stems can help to control stem dieback.

List to Know

• Do not forget to water your rhododendron arboreum plant regularly.
  
• Place your plant in an area with bright, indirect sunlight.
  
• Keep the soil moist but not soggy.
  
• Fertilize your plant every month during the growing season.
  
• Prune your plant regularly to encourage new growth.
  
• Keep an eye out for pests and diseases.
  
• Repot your plant every two to three years.
  
• Propagate your plant by taking stem cuttings.
  
• Overwinter your plant indoors if you live in an area with cold winters.
  
• Enjoy your beautiful rhododendron arboreum plant!

You May Like

• Rhododendron arboreum cathayense (Hemsl.) Rehder
  
• Rhododendron arboreum deciduum (Hemsl.) Rehder
  
• Rhododendron arboreum lutescens (S. Moore) D.F. Cha

Source:
Rhododendron minus - North Carolina State University
Rhododendron | PPO Home | Washington State University
Pests of Rhododendron | NC State Extension Publications