This time of year many gardens are bursting with colour from rhododendrons. These stunning plants come in a variety of different colours. Rhododendrons are also some of the easiest shrubs to care for. Once they are established, they are very low maintenance. If you have an active lifestyle or are new to gardening, this plant will be the perfect match for you.

In today’s blog, we break down the ins and outs of growing and caring for these beautiful plants. If you always wanted to grow a rhododendron, but didn’t know how, you’ve come to the right place. So grab your gardening tools, and let’s dig in!

Best growing conditions for rhododendrons

Although rhododendrons can grow in a variety of conditions, they do best in acidic soil. They also like to be adequately watered. Rhododendrons can handle some sun, but they prefer to have filtered light. Once established, rhododendrons require minimal care. This makes them a great choice for low maintenance landscaping. Here is a list of the best growing conditions for your rhododendron:

Can rhododendrons be planted in sun or shade?

Rhododendrons prefer to grow in an area of your yard which has some shielding from hot afternoon sun. The preferred location is part shade or an area that gets filtered light.

What soil is best for rhododendrons?

Although rhododendrons prefer moist soil to grow in, too wet and it can lead to root rot. They will also struggle in soil that is very compacted or which has poor drainage. Rhododendrons thrive best in soil that is acidic. Rhododendrons also like to grow in soil that is rich in organic matter.

How much water do rhododendrons need?

Rhododendrons will need to be adequately watered until established. Once established, water during hot spells or if the soil dries out. Since rhododendrons have very shallow roots, if the plant is left to dry out too much, it will cause harm to the plant.

What climate do rhododendrons prefer?

Some rhododendrons tolerate heat and humidity quite well and others are very cold hardy. Before you plant, always check the hardiness zones that the plant will thrive in. In general, most rhododendrons do not like strong winds or extreme temperature swings. 

What fertilizer is best for rhododendrons and how do you fertilize them?

There is usually no need to apply extra fertilizer to your rhododendron if you have very rich soil. If your soil is not acidic enough, you may need to apply fertilizer to adjust the pH level. Look for a fertilizer that is designed for acid-loving plants. These fertilizers should be applied in late winter or early spring.

Can you grow rhododendrons in pots or containers?

Yes, you can successfully grow rhododendrons in containers. However, there are a few things to keep in mind. Since rhododendrons have very shallow roots, you need a container with proper drainage. Rhododendrons are prone to root rot. Having a container with proper drainage will help to keep the roots healthy and happy.

As the plant grows, you may need to increase the size of the container. When placing your container in the garden, choose a spot that has filtered light. You will also need to overwinter your rhododendron properly since it is growing in a container. The best location to overwinter your rhododendron is in an unheated garage or basement. Here, the roots can be protected from freezing temperatures.

Frequently asked questions about rhododendrons

When should you plant rhododendrons?

The best time to plant rhododendrons is in the spring. Wait until the danger of frost has passed.

What is the size of rhododendrons?

Rhododendrons come in a wide range of sizes. Some are dwarf varieties that grow closer to the ground. These varieties tend to be about 16 inches tall. Other varieties can grow like a tree and reach up to 20 ft. Before you plant, always check with your local nursery or read the label on the plant to see if it is right for your space.

How do you plant a rhododendron?

Plant the root ball of your rhododendron as deep as the container that it was purchased in. Make sure to water well after planting. Continue to regularly water until it is established. Avoid planting in an area that is extremely wet. Being too wet can lead to root rot. Root rot can significantly damage your plant. Choose an area of your yard with well draining soil. Once planted, spread some mulch around the base of the plant to help it get established.

How do you care for rhododendrons?

Even though rhododendrons are fairly low maintenance and easy to care for, there are a few different aspects to keep in mind. Here’s a list of the top care tips for rhododendrons:

How do you prune rhododendrons?

If you want to prune out dead or broken branches and diseased areas of your plant, anytime is a good time. However, if you are looking to shape your rhododendron or to thin it out a bit, wait until it is done blooming. Don’t wait too long though. If you wait until late summer into fall, this is when your plant is forming next year’s flowers. Trimming then will interrupt next year’s flowers.

How do you protect rhododendrons in the winter?

Cold winter winds can damage next year’s blooms. If your plant is shielded from the winds, no need to add extra protection. If your plant is on the smaller side, you can wrap it with burlap over winter. Wrapping with burlap will help protect next year’s buds.

What are some pests and diseases that affect rhododendrons?

Common pest problems are:

• aphids
• mites
• mealybugs
• scale
• thrips
• whiteflies

Common diseases are powdery mildew, leaf spot, rust, root rot, and blight. The best way to keep your plants healthy is to provide them with what they need to survive.

Can you grow rhododendrons from cuttings?

Yes, rhododendrons can be grown from cuttings. Best time to take cuttings is in early August. Make a 6 inch cutting from the thin side shoots. Dip the cutting in some rooting hormone and then place in sand, vermiculite or a well-draining potting mix. Once rooted, cutting can be transferred to larger containers to continue growing.

Common problems with rhododendrons

Rhododendrons not blooming? Here’s some possible reasons why:

Bud damage

Sometimes extreme cold during the winter can damage the buds for next year’s flowers. Or, you may have accidentally pruned them too late. If you find yourself in either of these situations, you must wait for the plant to recover next year.

Improper light

Rhododendrons do not like direct sun, but they still need it to survive. Too much shade, and it will impact their blooms. Try pruning other plants around it that might be blocking the sun too much.

Stress from dry conditions

Blooms can be affected by drought-like conditions. When it is too dry out, try watering more regularly so that your plant does not become stressed.

Improper soil condition

The level of nitrogen and pH in your soil can cause problems for blooming. Too high of nitrogen and you may only get a lot of leaves and very little blooms. Remember, rhododendrons are acid-loving plants. Getting the right pH level is key to having beautiful blooms. When in doubt, consider having a soil test done.

Rhododendrons struggling to survive? Here’s some possible reasons why:

• Pest pressure: Some common pests that can cause problems for rhododendrons are mites, thrips, aphids, scale, or whiteflies.
• Diseases: Some common diseases with rhododendrons are powdery mildew, blights, root rot, leaf spot, and rust.
• Leaves turning yellow: If your rhododendron’s leaves are turning yellow, the pH level of your soil might be too high. Perhaps your plant is too close to a concrete sidewalk, home foundation, or driveway. The concrete might be leaching too much lime into the soil which raises the pH. The best way to know is to get a soil test done and amend the soil as necessary.

Landscaping ideas for rhododendrons

If you are looking to add a privacy screen to your yard, tall varieties of rhododendrons will make the perfect compliment to your project. Medium sized rhododendrons are perfect for lining walkways and paths or creating a beautiful garden border. Lower growing rhododendrons can be used to create lines along a building or in front of other taller plants to add depth to the garden.

Companion plants for rhododendrons

When it comes to rhododendrons, there are a lot of fun and interesting plants that grow well with them. For a colouful display, try interplanting

• astilbes
• alliums
• bleeding heart
• columbine
• azaleas

Final thoughts on growing rhododendrons

If you’ve always wanted to try growing rhododendrons, but never knew how, today’s guide is full of tips to help you get started. Until next time gardening friends, make this the year you try planting a rhododendron in your garden. Who knows, it just might become one of your new favourite plants!