Rhododendrons (Rhododendron species) are beautiful flowering shrubs that will keep producing gorgeous flowers year after year. If you are looking for a flowering shrub that thrives in shady locations, then rhododendrons are your best bet. The best part is you don’t need to do much for your rhododendrons to produce beautiful blooms. Perfect for the lazy gardener. Here are tips on how to grow rhododendrons in your garden.
Tips on How to Grow Rhododendrons
1. Your Rhododendrons are Happiest in Part Shade
Rhododendrons will do well in part-shade locations. They will grow best in a location with filtered shade away from strong winds. Don’t plant your rhododendrons in deep shade, it will not flower.
2. Get the Soil Right for Your Rhododendrons
Rhododendrons need to be planted in well-drained, slightly acidic soil (pH 4.5-6). Rhododendrons don’t do well in alkaline soil.
3. Get the Watering Frequency Right for Your Rhododendrons
Water rhododendrons once a week since rhododendrons have shallow roots that can easily dry out. They need moist but well-drained soil.
4. Fertilize Your Rhododendrons Sparingly
Rhododendrons don’t need to be fertilized to produce beautiful blooms. Only fertilize if you notice declining blooms. Fertilize sparingly in the early Spring or after the first flowering.
5. Rhododendrons Don’t Need to Be Pruned
Rhododendrons don’t need to be pruned. Just remove dead branches. If you do need to prune your rhododendrons, do it right after it blooms.
6. Your Rhododendrons are Irresistible to Deer
According to Rutgers University, azaleas are not deer resistant. They are rated occasionally to frequently severely damaged by deer. However, from personal experience, I have not had any deer damage with my rhododendrons but maybe cause I have hostas planted near them and they prefer the hostas!
Facts About Rhododendrons
| Name | Rhododendrons |
| Botanical Name | Rhododendron species |
| Zones | 3-11 |
| Sun or Shade | Part Shade |
| Soil | Well-Drained, Slightly acidic soil |
| Bloom Time | Varies- Spring to Summer |
| Flower Color | Many Colors-Pink, White, Purple and Red |
| Height | 5-20 feet |
| Deer Resistant? | No |
| Toxic to Pets? | Yes |
Tips for Planting Your Rhododendrons
Where is the Best Place to Plant Rhododendrons?
Plant rhododendrons in a shady location that receives filtered light away from strong winds. Avoid planting in deep shade because your rhododendrons will not flower. If you are in colder climates (zones 3-6), plant it in a location that receives more sunlight.
Rhododendrons have shallow root systems, it needs to be planted in moist, well-drained soil. They need soil that is slightly acidic, avoid planting near foundation walls since the surrounding soil can be slightly alkaline.
How to Plant Rhododendrons?
Before planting your rhododendrons, you need to prepare the soil first. Prepare the soil by making sure it is acidic and adding compost. You can add soil acidifier to make the soil acidic. Dig a hole that is as deep as the root ball and 2x as wide as the root ball. Don’t dig too deep since rhododendrons have shallow root systems! Top with soil, mulch, and compost. Water thoroughly.
When is the Best Time to Plant Rhododendrons?
The best time to plant your rhododendrons is in the Spring.
Rhododendrons: Frequently Asked Questions
Rhododendrons: Varieties
Popular Rhododendrons varieties are Rhododendron catawbiense and PJM hybrids.
Is Your Rhododendrons Toxic to Pets?
Rhododendrons are toxic to pets. Use fencing to keep your dogs and cats away from your rhododendron shrubs.
What Fertilizer Should You Use on Your Rhododendrons?
Use acidic fertilizer specifically for rhododendrons.
How Big Do Your Rhododendrons Get?
Rhododendrons can grow to 5-20 feet
How Do You Propagate Your Rhododendrons?
You can propagate rhodendrons from stem cuttings. Simply cut off a 4 inch long stem from any rhododendron branch. Avoid cutting from branches where the leaves have turned brown. Dip the rhododendron stem in rooting hormone and then plant in moist soil or sand. Keep the stem cutting in part shade and watered. Wait for the roots to develop. You can check occasionally by gently tugging on the cutting, if there is resistance, then you know there are roots. Be patient, it takes approximately 2-4 months to develop roots.
How to Choose Healthy Rhododendrons to Plant?
Choose a rhododendron plant without flowers. Also, look for dark green foliage. Avoid buying rhododendrons with pale green foliage. Check that the roots are strong (pull it out of the pot and it should not break off) and that there are no signs of diseases. Also, make sure the soil is moist. Don’t buy potted rhododendrons with dry soil.
What’s the Difference Between Rhododendrons and Azaleas?
The difference between rhododendrons and azaleas lies in the flowers and foliage. Rhododendrons are evergreen shrubs while azaleas are deciduous or semi-evergreen (some leaves don’t fall off in the winter). The flowers are also different. Most azalea flowers have 5 stamens while rhododendrons have at least 10 stamens.
What are the common problems that afflict Rhododendrons?
Common problems for rhododendrons are root rot, mites, scale, leaf blight, powdery mildew, and leaf blight.
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