QBARS - v17n3 Species Project Reports

Species Project Reports
Milton V. Walker, M.D., Eugene, Ore.

The Species Project of the A.R.S. would like to make available some of the information gathered by local committees and checked by members of the A.R.S. Committee with the full knowledge of its incompleteness. In the short time the Committee has been functioning it has been physically impossible to locate all the best forms of a given species even in the Pacific Northwest, or to definitely state which ones are "typical" or representative of the species. However many fine forms have been found and we have been asked to publish a short description of these plants and state where they may be seen and studied.

The plants described below, by their growers in most cases, are fairly mature plants according to our standards in the U. S. A. In the committee's judgment these plants are outstanding representatives of the species and conform to the published botanical descriptions. Undoubtedly there are many others just as outstanding and one reason for starting publication of our findings is to uncover other fine forms.

R. calophytum
Fig. 25. R. calophytum in full bloom in
garden of Dr. Phetteplace.

Rhododendron calophytum

This plant was grown from seed by the late James Barto with no existing record as to the explorer or its number to identify its source. It is probably 30 years old and began flowering 15 to 18 years ago. It has missed a year occasionally but generally is covered with trusses. In February 1962 it was very heavily budded and almost ready to flower when the temperature suddenly dropped to 15 degrees Fahrenheit. Although the plant has never shown any injury, this unusual cold destroyed all the flowers and there was only one truss that year.

Calophytum means "beautiful plant" and it is that indeed. The fine plant now growing in my garden near Eugene, Oregon is presently about 10 feet tall and 14 feet across. Although one of the Fortunei series it is considered one of the "big leafed" species, with leaves 14 to 16 inches long and 3 to 3½ inches wide. A characteristic is the collar-like arrangement of the leaves on the branches.

The truss is rather flat topped and has 25 or more flowers. This specimen has especially deep pink flowers which are accented by the almost red pedicles, which are 1 to 1-1/2 inches long. There is a rather prominent deep maroon blotch in the corolla. Another distinctive characteristic is the stout style capped by a discoid stigma 1/s of an inch across. The leaf scales are red and the new growth is striking with the bright green upper surfaces and white floccose undercoating which is quickly lost.

R. calophytum is such an outstanding rhododendron that it probably should be used more in hybridizing. Two of its progeny are 'Avalanche' and 'Calstocker', both fine varieties for the larger garden area.


Eugene, Oregon

With the exception of a very large and very fine plant in the garden of Mr. and Mrs. Ted Greig at Royston, Vancouver Island, B.C. the plant described above is, in our opinion, one of the finest now growing in the Pacific Northwest. Other very good forms may be seen at the U. of W. Arboretum, the Test Garden in Portland, Oregon 'and at Hendrick's Park, Eugene, Oregon. Variations in color from the usual pink shade, which may be very light to a dark pink, may be found in plants growing in the gardens of Halfdan Lem of Seattle, Wash., and H. J. Larson of Tacoma, Wash.

- M. V. W.

Rhododendron thomsonii

A Rhododendron thomsonii was given to us by some friends about 1947. The plant was then about 2½ feet tall and possibly around 10 years old. We have grown it in full sun until the last 3 years when we moved it to a position where it gets afternoon shade. It has now reached 6 ft. tall, 11 ft. wide and 25 ft. in circumference 1 ft. above the ground. Our plant has been blooming for about 8 years only sparingly, however it bloomed profusely one year. The flowers are a good red and a little larger in size than the typical, as described in the "Species of Rhododendron." The leaves of our plant correspond to the usual description of a somewhat orbicular lamina with rounded apex and blunt mucro. Kingdon-Ward in his book "Rhododendrons" says that Rhododendron thomsonii forms a handsome shrub 10 to 20 feet high and almost as much through. He could be describing the plant now growing in our garden in Seattle. The local species committee tagged this plant as a superior form on its habit alone.


Seattle, Wash.

Most plants of R. thomsonii checked by the A.R.S. Committee were found to be tall, rangy and not particularly attractive as garden plants. Occasionally we found a compact and well shaped plant, usually growing in more sun than the average, but in one garden two plants growing side by side showed definitely different growth habits leading us to wonder if there are actually two forms of R. thomsonii. Let readers be advised that "full sun" as described by Ralph Jacobson above, is for the Seattle-Tacoma area and is equivalent to probably half sun in the Portland-Eugene area.

We have selected the plant described by Ralph Jacobson to bring out the difference in growth habit and to emphasize the fact that a well grown and cared for plant of R. thomsonii can be an exceedingly handsome shrub as well as breathtakingly beautiful when in the full bloom of maturity.

Many of the fine specimens of R. thomsonii to be found in the Seattle area originally came from an exceptional batch of seedlings grown by Herb Ihrig, Bainbridge Island, near Seattle. Mr. Ihrig received his seed from Darjeeling, India in the early 1930's. He has kept a few plants, and now has some extraordinarily beautiful ones 10 to 12 ft. tall and as much in diameter. The writer had the great privilege of seeing these plants in full bloom this spring. The beauty of the large ruby red waxy flowers will long be remembered. In Tacoma, Wash. good forms may be found in the gardens of Herbert Bowen, H. J. Larson and others. The late Rudolph Henny had a good R. thomsonii in his garden and other good ones may be seen in the Test Garden in Portland and in the garden of Dr. Carl Phetteplace of Eugene, Oregon.
- M V. W.

R. yakushimanum

Our plant of R. yakushimanum F.C.C. was obtained from E. R. Peterson about 1954. He received the cuttings from George Grace, to whom they had been sent by Francis Hanger from Wisley in 1950. The Wisley plant came from Exbury as a layer from the original plant imported by Rothschild from Wada in Japan.

Our plant is now about thirteen years from a cutting and is about thirty inches high and fifty-six inches wide. It is dome shaped and very compact. It buds well every year, and many buds are removed in the fall to keep them from being too crowded.

It is exposed to the summer sun from about nine in the morning until three in the afternoon. The temperature may go above 90 degrees as many as fifteen times during the summer with daytime humidity in the twenties and sometimes lower. The low humidity is pleasant for people but a test for rhododendrons. R. yakushimanum appears to stand more sun than the great majority of the genus. The foliage is a little larger and darker on the north side of the plant than on the south side. Perhaps the ideal exposure would be in the open except for light shade for four or five hours in the middle of the day.

R. smirnowii, R. metternichii, R. makinoi and R. degronianum require more shade than does R. yakushimanum .

This plant has good drainage next to a four foot dry rock wall. It is in silty clay loam with some fir sawdust incorporated and has a constant mulch of fir needles. Nitrogen and sulfur are added once a year in March. It has had no die-back and the leaves stay on for six years, the longest time that I have observed in either species or hybrids.

The horticultural virtues of R. yakushimanum have been so thoroughly aired in the literature the last few years that I shall make only a brief summary.

The leaves are thick, glossy and dark green on the upper surface when mature and have a heavy, bright tan indumentum underneath. On the developing foliage there is a white frosty indumentum both above and below as well as on the stems. This display is as striking as that of any species that I have seen although on a smaller scale than some, and it lasts for at least two months.

There are about eleven cup-shaped corollas in a compact dome-shaped truss. The spacing could not be improved.

The flowers have much substance and last well. The expanding buds show a bright, clear pink and gradually turn light as they open. The fully open truss is pure white with a waxy shine. At the stage when about half the trusses are fully open and the other half show their bright pink opening buds R. yakushimanum is unmatched in its beauty and evidence of quality. In short, the word quality would be the word to describe the plant in all its stages of growth.


Aurora, Oregon

Mr. Jock Brydon imported from Exbury a plant now in the garden of Bob Comerford of Marion, Oregon, and from which many plants now growing in this vicinity owe their origin. All are alike, but none we think are as beautifully grown as the one described above. The only plant of any size we have found north of Portland is a very nice one growing in the garden of Fred Robbins of Puyallup, Wash.

- M. V. W.

R. metternichii var. tsukushiana

This plant was purchased in 1946 from a row of seedlings grown by H. L. Larson of Tacoma, Wash. It was about 8" tall, compact and supposedly a dwarf type of rhododendron well suited for a sunny location. It was about 8 to 10 years old at the time of purchase. Two or three years later when it bloomed for the first time we identified it from the Species Rhododendron book as R. metternichii . Mr. Larson later confirmed this identification and then gave us the Japanese varietal name of tsukushiana .

Our plant has been grown where it receives only early morning sun. It puts out from 4 to 6 inches of growth a year and now stands a full 6' tall and 8' in width. The mature leaves 'are 6" long with a dark-green, glossy surface. The underneath is a beautiful, tawny color, the indumentum being so fine it gives the effect of a hard, shiny surface. The prominent mid-rib is a light green color.

The flowers are campanulate, light pink in color with a few reddish freckles. They are 7 lobed, 9 to 12 in a truss, each floret supported on a 1½" pedicel. This is an excellent foliage plant as well as one having beautiful flowers.

At the time we purchased this plant there were six others purchased by members of my family; however our plant seems to be superior to the other six, though they are all beautiful specimens. Four of these plants are now to be found growing in the National Test Garden in Portland, Ore. Two are at the top of the rockery and two are located in the species plantings along the west side of the Island.


Portland, Ore.

Mr. H. L. Larson of Tacoma has three distinct forms of R. metternichii growing in his garden, all of them very beautiful either in full bloom or as an interesting foliage plant. In the Eugene area Dr. Phetteplace has a good plant about 5 ft. tall and in Portland there are the plants in the Test Garden but none as fine as the one described above growing in the garden of Ruth and Ted Hansen.

- M. V. W.