Rhododendrons in the Landscape
Dick Leonard, Raynham, Massachusetts
Reprinted from "The Rosebay", Newsletter of the Massachusetts Chapter
The genus rhododendron offers many landscape uses even in the difficult and varying climates of Massachusetts. Unfortunately, however, the attraction between man and plant has led to widespread misuse in many home plantings.
Surely all of us have seen, and many of us own, examples of mature large-flowered hybrids which are threatening to push the house off its foundation, which successfully shut off all daylight from first floor windows, or which sprawl out at grotesque angles from the foundation plantings reaching for more light or growing space. These were planted, of course, with the best of intentions and tender loving care by people who purchased them as "cute" 18-24 inch plants but with no thought or knowledge of their ultimate size.
Those people who own large homes of the Victorian era or of the early 20th century may still use the larger hybrids to advantage. However, owners of Capes or Ranch homes should restrict their use to marginal or screen plantings. If they are fortunate enough to have a natural wooded area on their property, they can establish them as an attractive underplanting.
What, then, is available to the small home owner who wishes to use the genus rhododendron in his foundation planting? First, there are among the large-leaf hybrids certain varieties which reach only medium height, four feet in ten or more years. Generally, these selections are spreading in growth and rather compact.
Such old favorites as 'Boule de Neige' and 'Cunningham's White' - both good whites - come to mind. Both do better in part shade, the former because there it is less susceptible to Lacewing damage, the latter to winter sunburn. Several of the Shammarello hybrids are semi-dwarf in their growth. Those often recommended are 'Besse Howells' (red with lustrous foliage), 'Cheer' (shell pink with red blotch), 'Sham's Juliet' (apple blossom pink, brown blotch), 'Sham's Ruby' (Blood red) and 'Tony' (cherry red). Another good old white, 'Chionoides', is very useful too. These are all supposed to take -20° F. temperature in their stride.
Several small leaf varieties are available and grow successfully in most of our area. These include 'PJM' familiar to all of us; 'Rampo' and 'Purple Gem', similar dwarf mound types with leaves less than an inch in length and blue-violet flowers early in May; 'Windbeam' (R. carolinianum x R. racemosum), which opens white and ages to a soft pink. This plant stands shearing, should it be necessary. 'Mary Fleming', although not familiar to this writer, sounds most interesting and is hardy to at least -15° F. Being a cross between R. racemosum and R. keiskei, it has small leaves and is a shapely and free-flowering plant which blooms pale yellow with salmon shading outside the corolla. An old variety much prized for its compact and dwarf habit is 'Laetevirens'. There are few plants that can surpass it as a foliage plant. However, the small rose-red flowers are fortunately, rather inconspicuous. Some of the Waltham hybrids, too, have excellent foliage, with compact growth and showy flower heads in shades of pink and white.
Dwarfs, such as R. impeditum, 'Purple Gem', 'Ramapo', the dwarf forms of R. keiskei and R. racemosum have a unique place in the rock garden or in a contemporary stone garden. They can also find good use as ground cover plants under the light shade of dogwoods, Japanese maples etc. In fact, the hot summer sun has proved too much for R. impeditum in my planting, and I shall try it again in part shade.
The old standby, R. maximum, is still very useful as a background plant because of its excellent foliage, especially in shade. It will even survive under the deep shade of maples if given the encouragement of good soil preparation and regular watering and feeding.
The large-flowered hybrids, to my mind, are best adapted to screen and marginal plantings, unless one is fortunate enough to own a large lot. There, the choice is limited only by the climatic conditions of your area.