Rhododendron & Azalea Care
Whether evergreen or deciduous, Rhododendrons and Azaleas, can add much needed color to the shady landscape. With proper care and plant choice you will be rewarded with a beautiful, blossoming shrub for many years.
There are many rhododendrons, with different degrees of hardiness. Always choose a rhododendron that is recommended for your area. Check plant tags and consult with your local garden center for recommendations.
- Rhododendrons and Azaleas, in general, prefer an acidic soil with a pH around 5.5.
- Make sure the soil is light and well drained. If you have heavy clay, amend well using compost and course/builders sand.
- How much compost and sand? First, plan on amending the largest area that is practical for your planting. Then, using a garden fork, loosen the top 6 inches of soil. Layer that area with 3-4 inches of compost and 3-4 inches of sand, mix well.
- Rhododendrons are available in either B&B (ball and burlap) or container grown.
- In colder areas, early spring planting is recommended.
- Any tree or shrub can easily be damaged or killed by planting too deeply. The top of the root ball should be at the surface of the ground or an inch or two above. Never plant deeper than they were grown in the nursery.
- Container grown plants: Water thoroughly before transplanting. Remove the plant from the container by turning the plant upside down. If you have difficulty removing the plant from the pot, simply cut off the container. If the roots have become overgrown and the root mass is in a tight circle, you must loosen those roots prior to planting. Use your hands to gently tease out the roots. If that is not possible, use a knife to cut the roots on two to four sides of the pot, starting at the bottom and going no more than half way up the sides of the rootball. Also, cut across the bottom in an X, than loosen the roots as best you can with your hands or trowel. Do not be afraid of damaging the plant, they are tougher than you think.
- B&B: Do not remove the burlap from the root ball. After you have placed the root ball in the hole, remove any rope/string that is tied around the trunk and untie the burlap at the top and stuff in the hole. The burlap will break down in about 6 months.
- Always pick up a plant by its root ball, never by its trunk or stem.
- Dig a hole 2-3 times the width of the root ball and the same depth of the root ball. Save the soil you removed from the hole.
- Place the root ball in the center of the hole and backfill with the soil you just removed from your newly dug hole.
- Water well to help settle the soil around the roots.
After Plant Care
- Rhododendrons are shallow rooted and the roots may dry out during the summer, so, water well during the summer, especially the first year after planting when the roots have not yet gotten out of the original root ball and into the surrounding soil. The general rule of thumb is to make sure the plant gets 1 inch of water per week (approx. 10 gal.) either from rain, watering, or a combination of the two.
- Mulch to conserve moisture.
- Because of their shallow roots, little or no soil work should be done around the base of Rhododendrons.
- Rhododendrons/Azaleas prefer an acid environment. Feed them using a quality slow release acid fertilizer. Apply fertilizer in early spring (March in more northern climates) and again in early summer (June). Do not feed again for the remainder of the growing season as fertilizer can stimulate growth, which may not harden off prior to early frosts, damaging new stems and leaves.
Pruning and Dead-Heading
- Normally very little pruning is needed. If you wish to maintain a specific size, remove no more than 1/3 of the plant per year. Pruning and dead-heading (removal of old flower heads) should be done immediately after blooming in order to avoid affecting the following year’s flowers.