QBARS - v15n2 Rhododendron Notes

Rhododendron Notes

A few years ago a prominent gardener told me he could not understand why "Unknown Warrior" had a one star rating as this variety grew well for him and had a truss that was outstanding for form, color and brilliance. His plants were growing in full sun. Where it is grown in half shade the branches grow leggy, droop badly and the number of blooms is much below normal.
It is helpful to know without learning through painful experience the plants that must have full sun in the San Francisco Bay area to perform satisfactorily. Other plants that need this situation are R. 'Dawn's Delight', 'Forsterianum' and 'Max Sye' and 'Jock'. There are probably many others, but with these we have had garden experience.
The need for good drainage for rhododendrons is constantly stressed in cultural literature, but it is left to each individual to interpret the implications of "Good Drainage" particularly as it may apply to the kind of garden soil he may have to contend with.
In my case it appeared that good drainage would be accomplished by digging a fairly large basin in the adobe soil, filling the bottom with gravel and back filling around the plant with a mixture of soil, sand and leaf mold or peat. This however does not provide the needed drainage for many "difficult" species and hybrids as I learned after losing about sixteen plants in the last two years.
To obtain the necessary drainage in adobe soil which is so prevalent in California it is necessary to dig in sand and gravel for an extended area around the plants.
We believe this condition has been a factor in the high rate of failure of such plants as 'Moonstone', 'Bow Bells', pemakoense , sanguineum , russatum and many other beautiful plants.
To obviate these conditions we are going to plant such varieties on top of the soil and fill in around them with light soil. This method of planting has been recommended by some of our members in the East, who have had to contend with heavy clay soils.
We will report later on results.

Flowers are out about one week earlier than last year. Blooming in this area February 16, are R. spinuliferum , 'Forsterianum', 'Cornubia', 'Glory of Penjerrick', racemosum , arboreum , grande , taggianum , delavayi and others.
A beautiful species is R. protistum , a plant 20 feet high is blooming in the University of California Botanical Garden. Dr. Evans took 35mm pictures with a telescopic lens of the gorgeous pink truss topping the tall growing rhododendron tree. We hope to show them soon at a Society meeting.
Blooming beautifully in the interesting garden of Mr. A. E. Jensen, a life member of the Society, in Berkeley is a dwarf arboreum about 18 inches tall with four full size trusses. We took a picture which will be shown soon.
- Edward H. Long, Oakland, Calif.

An experience new to me at least has been enjoyment of Azalea 'Albert and Elizabeth' for well over two months. Planted in the garden until just before frost, brought into the house it opened its first buds December 20. In early March it still contained a few blooms.

While the West Coast has enjoyed a mild winter, the east has had a rough one. Some rhododendrons have been killed; many flower buds were frozen. Azaleas have been badly burned but most flower buds came through.

The Philadelphia Chapter A.R.S. has just entered a long range program of developing a chart for azaleas as to hardiness and merit. The range of the Glenn Dales, for instance goes from very hardy to borderline. Labeling will also enter the program. There are so many azalea clones, many of which are nameless seedlings when sold yet are very beautiful.

This winter in Philadelphia has proved how extremely variable hardiness ratings are. Minimum temperatures at members' homes ranged from zero to minus 14 F. Therefore, in recommending clones for the area, we must qualify them as to an extraordinarily severe winter, and possible use of more tender plants.

Along the lines of hardiness and the severe winter we have had it is quite possible that the effect may be a revision on hardiness of certain clones. The writer has R. 'Britannia' in very good condition, while R. 'Cynthia' nearby is badly burned. President Jefferis has R. 'Earl of Athlone' in his garden at Media and with little protection it has wintered well.
- Besti Kelius, Philadelphia

Rhododendrons change color from bud stage to fading, which is glorious in itself but it can create problems in placement for color harmony. Here are some examples:
Rhododendron 'Carita Golden Dream', listed as a yellow, was planted near Magnolia Lennei as they bloom together. R. 'Carita' is a double-crosser who bursts forth with orange-yellow buds and stays that way in flower for quite awhile before fading to pale yellow. Sentence was passed and R. 'Carita' was banished to a place near Pieris japonica , whose bronze new growth pays proper tribute to her beauty. Cream colored 'Unique', with a slightly pink bud, took R. 'Carita's former place and is just right.
Ostbo's form of R. 'Moonstone' was near a pink camellia as well as Rhododendron 'Bluebird.' Out came the orange-yellow buds and out came 'Moonstone', to be placed somewhere else with blue.
Other examples are yellow R. 'Idealist', orange-pink buds; yellow R. 'Letty Edwards', unusual pink buds; apricot 'Elspeth', scarlet buds; pink 'Dawn's Delight', brick red buds; 'Loder's White', pink buds and pink for awhile after flowers open.
This is not a condemnation of changeling rhododendrons. They are all beautiful with the correct companions and the changing feature usually is not a disturbing factor. However, if certain effects are desired, it is well to find out the color stages. Instead of merely ordering rhododendrons from catalogs by blooming season under the general headings of white, apricot, yellow, etc.

There is a good bud set in Seattle this year and the winter has been mild so far. Prunus subhirtella rosea started a month ahead of its usual blooming time. Early rhododendrons, including sutchuenense at the University of Washington Arboretum, are about three weeks earlier than usual. We are keeping our fingers crossed that there will be no radical change in the weather pattern in the next few weeks.
- Ruth Jacobson, Seattle, Washington

Another early mixed-up spring. As these "Notes" are being written on March 24, R. 'Moonstone' is nearly in bloom while just a bud or two on R. thomsonii barely shows color. Buds on Knaphill azaleas are swelling and look as though they could bloom next month. We have had rhododendrons in bloom for over six weeks.

First to bloom for us was R. moupinense , a pink and a white form planted together put on a wonderful show. We have never seen them so good. R. 'Tessa' was spectacular and blooming with 'Bric-a-brac' was most attractive. 'Cilpinense' was loaded with flowers and not a single bud lost to frost. R. mucronulatum 'Cornell Pink' bloomed well on a small plant; we thought it the finest form of this species we have seen.

"Organic Gardening," November, 1960, carried an illustrated story of "Growing Rhododendrons in Levittown." A most interesting account of how Mrs. William A. Kelius, Pennsylvania contributor to this column, gardens under difficulty on low ground where drainage is poor. Rhododendrons like good sharp drainage and Mrs. Kelius gets it by planting her shrubs on top of the ground and covering the root balls and in between with a mixture of oak leaf mold, peat moss and good topsoil from a nearby farm. They are then mulched with pine needles. She has raised her beds by this means eight or ten inches. The beds are retained by edging with a border of medium-sized rock. (It is rumored that one choice rock came from the lawn of the Levittown police department.) This is a fine story of how rhododendrons can be grown by a good gardener under great natural difficulties. Your public library probably has a copy of this publication. It is well worth reading.

We are sometimes asked, "Will this rhododendron bloom?" We have never heard of a plant which would not bloom in time, but some certainly do take their time about coming to blooming age. Often these slow-bloomers make up for it by being wonderful foliage plants, with handsome leaves, often extra large, sometimes with a white, grey, light or dark brown indumentum on the under side. They are among the most beautiful plants one can grow in a garden.
- Bob Boveee, Portland, Oregon