Summary: Many in the Northwest limit Rhododendrons in their garden to just a few plants – Why? There are many smaller varieties for even the small landscape.
Why limit rhododendrons in your garden to one or two majestic plants? With the many new dwarf-to-medium-sized varieties now available it’s possible to enjoy numerous specimens of the Northwest’s royal shrub in the smallest yard or beneath a window of the most rambling one-story house. And the smaller plants have all the outstanding qualities of the older towering shrubs.
Rhododendrons Unequaled
Where climatic conditions warrant their use, rhododendrons are unequaled. In rock gardens, informal hedges. foundation plantings and borders they provide magnificent flower color in springtime and beautiful foliage and sturdy form all year round.
Most of the newer compact types originated in England and many are hardy on Long Island and in sheltered gardens in New Jersey. Gardeners in Delaware, Virginia, North and South Carolina, Georgia, Tennessee and the cooler parts of Florida have also reported success with the hardier varieties.
In time, the interesting leaf forms and clearer flower colors of the newer rhododendrons may be combined with the rugged character of native species so that gardens in Maine can share the splendor now limited to milder regions.
Northern Or Eastern Exposures
When using rhododendrons in foundation plantings it is desirable to choose northern or eastern exposures for the plants. They will do as well on the other sides of the house, however, if there is high shade to protect them from afternoon sun. Trees, fences or screens can often he arranged to protect these broad-leaved evergreens from direct burning sun and drying winds.
All but a few rhododendrons require acid well-drained soil. When planting them against a new home it is advisable to dig down around the foundation and remove any debris dumped there by the builder.
Then coat the cement with asphalt paint to prevent outward movement of free lime from the foundation walls. Even in the acid soil of the Willamette Valley in Oregon there are evidences of “lime poisoning” where rhododendrons have been planted near cement foundations.
To insure having a properly acid soil, incorporate humus in the form of peatmoss, decaying leaves or pine needles. This also makes the soil loose and easily penetrated by the exceedingly fine rhododendron root system.
Make the planting hole much larger than the rootball of the shrub being set in it. Drainage will be improved by breaking up the soil in the hole bottom. Since they are surface feeders and languish if planted too deeply, rhododendrons are planted so the top roots are 1 inch below the surrounding soil level.
When the soil has been firmed, shape a large basin around the base of the plant and fill it with water three or four times, Then apply a mulch of pine needles, leafmold or bracken fern to protect the roots from drying winds and sun and conserve moisture in dry weather. The mulch ultimately becomes a source of food.
Rhododendrons take up quantities of water when putting on new growth, but overwatering is disastrous, particularly if drainage is poor. Most native rhododendrons grow where humidity is relatively high and they appreciate overhead sprinkling during evenings or mornings when weather is hot.
Small and Compact Rhododendron
The smallest of these rhododendrons are excellent for rock gardens where they thrive on slopes facing east or north or in the lee of large rock outcroppings. Low informal hedges are appropriate in the foreground of shrub borders.
Medium-Sized Rhododendron
These rhododendrons vary in height front 5’ to 8’ feet. They can be used in shrub borders or in plantings around houses, but the young plants should not be placed beneath low windows or where they might encroach on walks. Space from 4’ to 6’ feet apart.
FGR-0453 by Jock Brydon