How do I take care of my rhododendrons? They flowered well in the spring, and I want to be sure that they stay in good condition.
Thanks,
Rhoda

Dear Rhoda,

[su_row][su_column size=”1/2″]It appears that you are already doing a good job on the maintenance of your plants. Rhododendrons and azaleas require little care once they are properly established. Two inches of mulch will keep down weeds. Mulch should be moved away from direct contact with stems to reduce diseases and insect damage. No cultivation should be done because the shallow, fine roots are easily damaged.

Use fertilizers specially formulated for acid-loving plants and follow directions. Apply about 2 pounds per 100 square feet to the soil surface. Cottonseed meal is also a good fertilizer. Fertilizing should be done in May or June, but do not fertilize after July 1. Late summer fertilization may force out tender fall growth that will be killed by the winter.

Many rhododendrons have been killed by over-watering in sites where drainage was faulty. Avoid excessive irrigation.

There is little need for pruning, but it is important to remove the flower clusters on rhododendrons as soon as flowering is complete. Failure to do this will reduce flowering the following year. Break out only the dead flower cluster, being careful not to damage the young buds clustered at its base.[/su_column][su_column size=”1/2″]

The two winter enemies of evergreen rhododendrons are sun and cold wind. Don’t be alarmed when leaves curl and droop on cold days; that is normal.

Large-leaved evergreen rhododendrons are sometimes subject to sunscald during winter. This is most likely to happen if the plant did not receive ample moisture before freezing in fall. The exposed portions of the leaf (usually the central portion when the leaf was curled) may become brown. This may also appear on the edges of some leaves. To prevent scorch, plants should be well watered in by November before the ground freezes; if rainfall has been sparse, protected from drying winds; mulched well and given some shade.

If leaves turn yellow in sections between the veins but the veins remain green, iron deficiency is the cause. If the entire leaf turns yellow with some browning, other problems are suggested. Chlorosis may result from soil that is not acid enough, poor drainage, nematodes or other conditions that cause root or stem injury. The application of 1¼  cups of iron sulfate per 100 square feet of bed area each fall appears to help harden growth for the winter and also helps prevent iron chlorosis.

—Elaine Fogerty,
Executive Director

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