How to Care for Rhododendrons
Rhododendron Plant is a large family of shrub. There are over 900 species with a wide range of colours, leaf size, and shapes.
They are large and small, deciduous and evergreen. Sizes range from 8 to 80 inches.
Late winter to midsummer.
This shade gardening plant requires a moist acid soil and does best in zones 2 through 8. Protection from winter sun and wind is important.
This shrub has shallow roots; you'll need to be careful when digging around them. Rapid freezing and thawing can be hard on them, so add about 3 inches of mulch. This will protect them in Winter and keep their roots cool and moist in Summer.
You will be able to tell when your soil is less acidic than optimal if you see leaves turning yellow while the veins are still green.
To acidify your soil, if necessary, is to prepare your own soil mixture. Use 1/4 soil, add to that 1/2 organic matter (peat moss, oak leaves, mulched, cedar or pine chips, and 1/4 clean sand will do the trick. I would also add some slow release fertilizer made for acid loving plants.
If you have a heavy clay soil you can use a raised bed technique. Mound the soil 6 to 8 inches above the clay, this will allow for necessary drainage.
Avoid manure as it is high in salts. Over feeding is a bigger problem than under feeding, less is better. You are starting out with a good mixture of soil and adding good mulch twice a year should be just about right.
These shallow rooted shade shrubs can't tolerate drought for very long. Water during a dry spell and keep 3 inches of mulch as mentioned above.
Grooming your Rhododendron plant consists of dead heading the spent flower heads. This will allow this shade gardening plant to use its energy to produce flowers and leaves for next spring.
Simply hold the branch with one hand and break off the spent flower with the other hand. Be careful not to damage any new growth.