How to Grow and Care for Catawba Rhododendron

Catawba rhododendron (Rhododendron catawbiense) is a multi-stemmed relative of the azalea that is grown mainly for its large clusters of lavender flowers. This slow-growing shrub loves shade. Its shallow roots must be kept cool and moist in well-drained soil that does not hold water or become boggy. It is an ideal plant for woodland gardens, particularly those with excessive shade. Do note, though, that all parts of this rhododendron shrub are toxic to humans and pets.

Catawba Rhododendron Care

Here are the main care requirements for the Catawba rhododendron.

• Grow in shaded areas because its sensitive root system does not like to be exposed to heat.
• Keep the roots cool and moist, but be careful to avoid wet feet—good soil drainage is essential to avoid root rot.
• Apply 3 inches of mulch around the plant's shallow root system to retain moisture, reduce heat absorption and cut down on weed growth.
• Be careful not to weed too vigorously around it, as this delicate and shallow root system can be easily damaged.
• Prune your Catawba rhododendron just after it is done flowering. Tardy pruning could cause a reduction in flowers for next year.

Light

Give Catawba rhododendron a little morning sun at the northern end of its range. At the southern end of its range, give it full shade.

Soil

Make sure that the soil for these shrubs drains well. If the soil does not currently drain well, amend the soil with organic matter.

Water

Catawba rhododendron has average water needs, but try to keep its soil evenly moist without making the soil overly wet or boggy.

Temperature and Humidity

Catawba rhododendrons prefer cool temperatures and high humidity.

Fertilizer

Fertilize Catawba rhododendron in spring yearly by working compost into the soil. Do not overfertilize.

Types of Catawba Rhododendron

• 'Purpureum Elegans: This cultivar produces bluish-purple flowers in spring and does well in the cold.
• 'Roseum Elegans': With blooms similar to that of a rose, this vigorous grower is common in New England.
• 'Nova Zembla': A type with unique lavender-red flowers and cold tolerant even at freezing temperatures.

Tip

Although this shrub is impressive enough to function as a specimen plant in your landscape, it is also an excellent bordering species. Plant several Catawba rhododendron shrubs together to create an attractive living privacy screen.

Pruning

Start by pruning off dead or damaged branches just after your rhododendron has finished flowering. Next, trim off any branches that are sticking way up above the rest, thereby spoiling the overall shape of the bush. Yearly pruning will promote a more compact shape.

Propagating Catawba Rhododendron

These shrubs can be propagated using cuttings in late summer or early fall after new growth has begun to harden. You'll need scissors, a plastic bag, a seterile mix of 60% milled sphagnum peat moss and 40% perlite, containers, rooting hormone with fungicide and azalea fertilizer. Here’s how:

1. Cut with scissors just below a node on a firm, hardened stem of this year's growth (cutting should be about 4 to 6 inches long).
2. Remove the bottom few leaves and any flower buds.
3. Dip the stem in water then in rooting hormone (if desired), and slide the stem about 2 inches into a container of mixed peat moss and perlite.
4. Keep the cuttings warm and moist but not soggy. Fertilize monthly with azalea fertilizer. Rooting should take place in 3 to 4 months.
5. Transplant the cutting into the ground during the summer.

How to Grow Catawba Rhododendron From Seed

Growing rhododendrons from seed is time-consuming, but it can be done. Here's how:

1. In February, sprinkle seeds on a small pot of equal parts moist sphagnum moss and perlite. Do not cover.
2. Place the pot in a clear plastic bag to keep humidity high and keep away from direct sunlight in a warm location, rotating the pot once a week.
3. The seeds will sprout in four to eight weeks and can be transplanted into other containers once they grow leaves. Keep the seedlings in containers for two years before transplanting them into the ground outdoors.

Potting and Repotting Catawba Rhododendron

Catawba Rhododendron can be grown well in containers because they have shallow root configurations. Make sure the pot is not too deep initially, about 8 inches, and that it has several drainage holes since it will not thrive in soggy soil. The best potting soil is slightly acidic and mixed with peat moss. Put the container in dappled sunlight and avoid direct intense sun. The plant will need more space as it grows and can be transplanted to a larger container when it is time. Before replanting, soak the root ball in water first to allow the roots to untangle.

Overwintering

In temperate areas, no winter care is needed. However, if you live in a region that experiences freezing temperatures, it's a good idea to wrap your rhododendrons in burlap to protect them. If growing in containers, move them into your garage or an insulated area.

Common Pests and Plant Diseases

Black vine weevils and thrips are the most common insect pests of rhododendrons. These shrubs are also susceptible to a bacterial disease called crown gall. Fungal diseases that may affect rhododendrons include various cankers and gray mold.

How to Get Catawba Rhododendrons to Bloom

Bloom Months

This rhododendron normally blooms in mid to late spring months so March through June.

How Long does Catawba Rhododendron Bloom?

The blooms can last on the plant anywhere from two to seven months depending on climate. In chillier weather, each bloom's life cycle may be shortened slightly.

What does Catawba Rhododendron's Flowers Look and Smell Like?

Catawba rhododendron boasts large, rounded, clusters of purple blooms.

How to Encourage More Blooms

To give your Catawba rhododendron its best change at a productive bloom season, add shade or frost protection, depending on if they flower early or late in the season. The plant may not bloom every year like clockwork and experience a period of rest after a heavier blooming period.

Make sure your plant has the necessary conditions of dappled sun and well-draining soil. Keep in mind that young plants may not bloom immediately.

Caring for Catawba Rhododendron After it Blooms

Trim off any dead or dying branches and foliages immediately after blooming is standard care for rhododendrons.

Deadheading Cawtawba Rhododendron Flowers

Make sure to prune your plant immediately after blooming, and deadhead the flowers to encourage new bud production. Plants experiencing a particularly heavy flowering season can be pruned or thinned out while still blooming to improve the quality and placement of the ones remaining and ones to come.

Common Problems With Catawba Rhododendrons

While Catawba rhododendron is relatively easy to grow in the right environment, you may run into a few common growing problems.

Leaves Turning Yellow

Yellowing leaves often indicate soil that is too alkaline; rhododendrons need acidic soil. You can amend alkaline soil with various acidic additives like minerals and fertilizers.

Wilting Leaves

If you notice wilting or drooping leaves, you may have waterlogged your plant. Make sure your soil is moist and well-drained, particularly if you live somewhere prone to heavy rains.

From: thespruce