Rhododendron Notes
Fall foliage in the northwest, has been particularly beautiful this year. The vine maple, native here, is always spectacular, but not less spectacular has been Acer ginnala , the Amur river maple of China. It makes a shrubby growth to 25 foot and selected plants can have wonderful red leaves in the fall. Forms of Acer palmateum in addition to being fine all-year garden plants, often color during the early winter months, some are brilliant red, others yellow, orange and bronze. If you are so fortunate as to own the very rare Acer griseum you have one of the most beautiful of fall foliage plants, leaves yellow and red, with curling golden bark reminding one of stock cinnamon. The different forms of Enkianthus are excellent fall plants as is Parrotia Persica , a tree not often seen. It has golden and crimson tinted leaves in the fall with many often carrying yellow and blue tones. One of our most handsome fall shrubs are the forms of Knaphill azaleas. These are handsome foliage plants any time of the year but in the fall leaves turn spectacular colors in shades of orange, yellow, and light and dark red.
Species perform differently in the moist humid climate of the British Isles with their low summer temperatures, than in this country. Here where it is hotter and drier many of the species, recommended as doing well in the sun by the RHS, will require partial and sometimes full shade. This is true of the Sanguineum subseries of rhododendrons containing such good plants as
R. aperantum
,
R. dichroanthum
,
R. didymum
,
R. haemaleum
,
R. himertum
,
R. temenium
and others. These plants do best for us in full shade. Leaves will often turn yellow and then drop when grown even in light shade. These are not among the easiest plants to grow but are fine foliage plants with excellent growth habits, well worth the extra effort. Flowers are usually in shades of red but
R. himertum
has lovely lemon yellow bells. These plants have done best in locations with excellent drainage and in woodsy soil without much peat moss around their roots. We have often thought they appreciate a soil containing sand and pea gravel. They bloom from seed in 8 to 15 years and should be planted in a permanent place when young. Moving will often kill old plants.
- Bob Bovee, Portland
At the dinner honoring Mr. Joseph Gable in November, the table favors were, appropriately, rhododendrons. At each place was a small potted plant of
R. myrtifolium
, with moisture-conserving polyethylene tied with red.
Mr. And Mrs. R. P. Jefferis Jr. of the Philadelphia Chapter, have been trying new plants as companions to rhododendrons for several years. One, a member of the Mint family is
Meehania cordata
, vine-like in habit, with lavender-blue flowers in the Spring.
Another group of relative newcomers to the Jefferis' garden is Daboecia Irish--heather--blooming all summer, until frost. This may be "old stuff" to the West Coast, but in the East it is often a question of trying new things that will possibly survive.
The establishment of a new flower bed in the Jefferis' garden, in full concern, this year, was of some concern. Mrs. Jefferis' answer to the moisture- conserving problem was to use the burlap in which the plants arrived, making a diagonal cut from one corner to the center, then arranging the burlap around the plant, on the ground. It worked quite well, keeping the sun from drying the earth.
Although the ultimate height of
Oxydendron arboreum
- Sourwood, or Sorrel Tree- is given as 75 feet, it is often referred to as a little tree, since it is slow-growing. In this part of Bucks County, at Snipes Farm and Nursery, there are a number of old trees, an Oxydendron, is above 40 feet, and a handsome specimen.
Last year I made the acquaintance of "The Cream of the Alpines" by the late Frank Barker. Since that time, three of the plants mentioned in the book have found their way into our rhododendron bed as foreground planting--Anemone pulsatilla, or Pasque Flower, fern-like in foliage and violet
blue in flower;
Astilbe simplicifolia rosea
, much dwarfer and daintier than those usually seen; and Dianthus Alpinus, pink-flowered on two-inch stems. The astilbe and dianthus have the advantage of providing a little color after the rhododendrons have finished blooming.
- Betsi Kelius, Philadelphia
During the last few days, the American Rhododendron Society has been invited to take part in two large horticultural shows. One is the World Flower Show to be held in Los Angeles during February and March, 1961. The other is the International Horticultural Exposition to be held in Hamburg, Western Germany, in 1963.
The Test Garden Committee has been working steadily this fall, and plans to put in a lot of time next spring, getting the Rhododendron Island in tip-top shape for the visitors. Most of the work has been, and is being, done by a very small but devoted group of volunteers who give a good portion of their weekends to this unselfish work.
The regular Rhododendron Show of the Portland Chapter will be held during the International Conference. Several new features are under consideration by the Portland group. It is hoped that one of these will be a showing of as many rhododendron species, growing in the Portland area, as possible. This is a large number, and if an adequate representation can be collected, it will make an impressive showing.
There seems to be increasing interest in the old hardy rhododendron hybrids in the West. These varieties may prove to be of special value in areas which have been considered marginal for rhododendrons because of high, as well as low, temperatures and alkaline soil. The old hardies are based primarily on R. catawbiense , which is native in areas in the Southeast where high summer temperatures are to be expected. I do not know that these varieties have any special resistance to alkaline soil conditions, but they do have vigor of growth which should be of value in offsetting any unfavorable growing conditions.
We understand the federal regulations requiring post entry quarantine because of the European Rhododendron Rust have been lifted. This rust is apparently distributed over rather large areas in this country. It has not attacked the spruce trees here as it is said to have done in Europe, indicating perhaps that a physiological strain, somewhat different from the European strain, is present here. Furthermore, it has not been a serious pest on rhododendrons, probably no worse than the native rusts which are widely distributed. Apparently the Plant Quarantine Branch of the U. S. D. A. has come to the conclusion that this is just another plant disease of relatively minor importance.
- J. Harold Clarke, Long Beach, Washington
The University of California Botanical Garden is now attempting to increase the range of species. In the course of alleviating the crowding of the garden, some material of Hybrid origin which the Golden Gate Park particularly wants to have, may be transferred there. The selection will be made on a plant to plant basis in as much as the Berkeley Garden will maintain both a collection of Hybrid and an increased number of species. The Rhododendron Dell should look even more beautiful after trimming work is completed.
Anyone visiting California should take the opportunity to visit this Botanical Garden with a wealth of horticultural rarities and some of the oldest and largest Rhododendrons in the state. In Oakland up to December 1st, we have had a very mild winter and many gardens have plants that are blooming prematurely. To mention a few;
R. yakushimanum
, R. 'Countess of Athlone', R. 'Lady Alice Fitzwilliams', R. 'Elizabeth', R. 'Max Sye', R. 'Confection' and
R. racemosum
,
R. megeratum
, R. 'Bo Peep',
R. odoriferum
and
Rh. sinonuttallii
are all throwing out new shoots, they do not seem to know that it is fall.
Dr. Bowman has several in bloom among them is a plant of beautiful R. 'Victorianum' which is nearly in full bloom but the flowers are not as large as they would be if blooming in spring.
Comment is made at times about the awkward growth habit of a number of otherwise outstanding rhododendrons among them R. 'Earl of Athlone' and R. 'Broughtonii Aureum'. We have experimented with keeping the branches tied in, while still small and find that in several months the wood hardens and you have a fine compact plant.
Mr. Wales Wood gave us a plant of R. 'Rubina' which had frozen down a couple of times in Portland and wanted us to try it out here. Well, the plant is growing beautifully. It has full green foliage with lovely silver under coating and no blemishes or burning. A full set of large buds and looks like a fine addition to any garden in this area. It is growing in full sun.
A plant of
R. kingianum
four years from rooting has three large buds and will bloom this spring. It has grown vigorously with striking reticulate, lanceolate foliage. It is one of my personal selections for top rhododendron.
In the Pacific Northwest in the fall of the year the gardens are beautifully colored by the frosted foliage of the deciduous azaleas but in our frostless fall weather in many sections of California we get little or no leaf coloration on the deciduous azaleas so must be satisfied with the spring bloom.
- Edward H. Long, Oakland, California