Siting Your Rhododendrons
What is a good site selection for planting Rhododendrons?
Rhododendrons naturally grow at the edge of a woodland environment so keep this in mind when selecting your site.
In the Shade? Yes, as long as it’s high shade. Lowest branches of trees should be 20-30’ off the ground.
In the Sun? Yes, but no more than 4 hours of direct sunlight per day. Morning sunlight is best. Some rhododendron’s are more sun tolerant than others.
Under or near a Maple tree? No, the roots of the Maple are surface roots and will compete with the roots of the rhododendron. The rhododendron will lose the competition!
Under or near a Black Walnut tree? NO, NO, NO, Black Walnut trees give off a substance called juglone which is toxic to many plants growing within its root zone. Ferns can live under them but not rhododendrons!
Under an Oak, Birch, or pine tree? Usually not a problem as long as the branches are trimmed 20-30’ off the ground.
Next to a wall? Not on the South side of a wall or house because the sunlight reflecting off the wall will burn the leaves of a rhododendron. If you’re adamant about planting in front of your house, make sure the plant is at least 4’ from the foundation wall and is not under the roofline where it will not receive adequate rain. You may also consider selecting a shorter variety of rhododendron so that in a few year’s time your windows won’t be blocked. Periodically check the PH of the soil as lime may leach out of the foundation walls and make it difficult for the plant to grow properly.
In the Middle of your lawn? Yes, as long as the amount of direct sunlight (morning preferred) is not more than 4 hours and your automatic sprinkler system does not water the rhododendrons or the spray does not touch the leaves. Lawns require more water than rhododendron’s and automatic systems will over-water your rhododendrons, leave them damp and at risk to disease. See "What is the best way to water a rhododendron?"
On a hill? Yes, drainage on a hill is usually pretty good.
At the Bottom of a hill? Yes, if the soil drains well.
In heavy, clay soil? No, unless you plant the rhododendron on top of the existing soil by mounding it and supporting the mound with wood ties, stones, etc. The important thing is the roots of the rhododendron are happiest (and healthiest) in well-drained soil. Clay soil does not drain well!
In a windy area? It depends. If the area is exposed to a lot of winter wind, the rhododendron will or could suffer from "winter burn". If this happens once every few years, it usually won’t kill the plant. It doesn’t look very good, however!
In sandy soil? Yes, sandy soil provides good drainage. However, you must be prepared to give some extra care, especially watering, to the plant during hot and dry summers.