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Journal American Rhododendron Society

Current Editor:
Dr. Glen Jamieson ars.editor@gmail.com


Volume 21, Number 4
October 1967

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Evergreen Azaleas
Augustus Elmer, Jr.
Chinauapin Hill Gardens, Pass Christian, Miss.

        The Evergreen Azaleas, which are considered one of the finest shrub groups, are natives of China, Japan and Formosa. Even when not in bloom they are beautiful foliage plants. Those who live in the southeast are very fortunate, since contrary to the common belief that Azaleas bloom for two or three weeks, by proper selection of varieties one can have blooms from January through June and again from September to December. Azaleas can be grown in full sun, but will do better in partial shade especially in the southeast where the summers are long and hot.
        For background or foundation plantings there are available the large varieties such as Southern Indian, Glenn Dales or the newer and more tender Hirados. For hedges and lower plantings the Kurumes can be used, or the last introductions of the late B. Y. Morrison, the Back Acre Azaleas. The Gable hybrids, Rose Bud, Mary Ann and Purple Splendor are good for low plantings and have done very well in this area. Although they were developed for northern climates, many of the Glenn Dales are also very good for low plantings. For edgings and rock gardens the Dwarf Kurumes which also take pruning very well can be used.
        The flowers of the Evergreen Azaleas have an orange-red, red, pink, purple, violet and white color range. There are no true yellows or true oranges. The flower forms are single, semi-double, double and hose in hose.
        The following is a list of types and varieties that have done well here in Southern Mississippi and which, with the exception of the Hirados, should do well in the whole area of the Southern Chapter.
        Southern Indian: Rapid growers. Make very large plants in a few years. Flowers are large, mostly single, and cold hardy in all the Gulf States. More of the little known Southern Indians should be grown such as 'Iveryana', 'George Lindley Taber', 'William Bull' (very double), 'Harry Veitch' and 'Flag of Truce' to name a few.
        Hirados: A new introduction but grown for years on the island of Hirado off Japan are rapid growers and make large plants with large leaves and very large single flowers up to five inches in diameter. Flowers are pastel and should be given some shade. They are more tender and are best suited for the lower south.
        Glenn Dales: Over 400 to choose from. They were developed by B. Y. Morrison at the U. S. Plant Introduction Station, Glenn Dale, Maryland. The flowers are mostly single but some are hose in hose and some are double. Colors range from solids to mottled, spotted, striped and edged. The plants are cold hardy to Washington, D.C. In the South many bloom both in spring and fall. The fall bloom is not as full as the spring.
        Kurumes: Are low growing and growth is rather slow compared to Southern Indians. Flowers are small. They can be single, hose in hose and semi-double. The plants are cold hardy and when grown correctly are covered with blooms in early spring.
        Pericats: With medium size flowers, they have good color range and bloom in trusses similar to Rhododendrons. They are cold hardy.
        Gables: Are slow growing and make medium size plants. Many are double and all are very cold hardy. Ones that have done well in the south are 'Purple Splendor', 'Mary Ann' and Rose Bud.'
        Satsuki: Are low, spreading and slow growing. Flowers are large, mostly single. They may be striped, edged or ruffled. They make good pot plants and are the Azaleas used in Japan for Bonsai.
        Back Acre: Azaleas developed by the late B. Y. Morrison at Pass Christian, Mississippi. These plants are slow growing. Ten year old plants rarely exceed four feet in height and are almost as wide. The flowers are single or double, may have white or light centers with colored borders. These plants are cold hardy to Washington, D.C.

CULTURE
        The most important part of growing Azaleas is soil preparation. It must be remembered that all Azaleas are acid loving and prefer a soil pH of 4.5 to 6.0. If the soil does not fall within this range, it can be adjusted by the addition of acid peat or ground sulphur.
        Too much cannot be said about the importance of soil preparation. In the case of a single plant, a hole should be dug at least one foot larger in diameter than the root ball of the plant. It should be fifteen to eighteen inches deep. The hole should be filled with a mixture that is loose, on the sandy side, and that contains plenty of organic material such as peat moss, leaf mold or ground pine bark. Pine bark can be purchased under a number of trade names and seems to have great possibilities, not only as a soil conditioner but in a coarse form as a mulch. If the plants are to go into a bed, it should be at least three feet wide.
        If your soil is strongly alkaline, it is better to build raised beds. This prevents the alkali from leaching into the beds. It is a little more work but it's better than a constant battle with a rising pH.
        A three to four inch mulch should be used, in the southeast, all year. In the summer, a mulch keeps the roots cool and retards the growth of weeds. In the winter the mulch protects the roots from the sudden changes in temperature to which this area is subjected.
        Pine needles and coarse ground pine bark are, in my opinion, the two best mulches. Others that can be used are sawdust, wood shavings, peanut hulls and many others.
        Many people over fertilize azaleas. If a good organic mulch is maintained and fairly good soil was used in the preparation of the hole or bed, further feeding may not be necessary. However, if fertilizer must be used a small amount of cotton seed meal is best, about two tablespoons for a two foot plant.

PROPAGATION (Cuttings)
        Evergreen Azaleas are propagated quite easily by cuttings. Time to make cuttings in the southeast is between June 1st and August 1st. The best time will vary from year to year and also will be different for different varieties. If in doubt it's better to be a little late than too early.
        Any kind of box will make a good cutting box so long as it's nine to twelve inches deep. Cut the box on a slant so that the back is about two inches higher than the front. This is done so that it will shed rain. Fill the box with a mixture of peat moss and coarse sand, 50-50 by volume. This mixture should be thoroughly wet but not dripping. Do not provide drainage as this cutting box will not require watering. When the box has been filled with about five to six inches of this mixture, pack lightly with a piece of wood or other flat object. Tack a piece of clear plastic over the box and let set for three or four days to make sure the peat moss is completely wet.
        Make cuttings from shoots that form behind old flower heads. Cuttings should be taken with a sharp knife and be four to five inches long. Remove all but the top two or three leaves. Dip cut ends in a rooting hormone and stick cuttings about two inches deep into rooting medium. After the box is filled with the cuttings they should be watered lightly to settle medium around cuttings. Now nail down the plastic to seal the box. Place the box in a place that gets good light but no direct sunlight. In about eight weeks most of your cuttings should be rooted.
        When the cuttings are rooted they should be transplanted to a cold frame containing a good Azalea mixture, or given some other kind of winter protection so as not to lose the growth made from August or September to the first frost, which will kill the new growth if it is not protected. Please note that if the sand and peat moss are thoroughly wet before the cuttings are placed in the box and the cuttings watered and then sealed with the plastic, no other watering is necessary.

PROPAGATION (By Seed)
        Evergreen Azaleas can be propagated from seed without much difficulty and will bloom in three to four years. However, they do not come true from seed.
        The following method has been very successful here. (1) Collect seed in late summer or early fall and store in a covered, but not airtight, container until the following February. (2) Prepare a flat using shredded sphagnum moss. Fill flat to top and set in a container of water, compress moss and let flat remain in water overnight. Next day remove flat and drain compressed moss. Then put flat back in water for at least three or four hours. Remove and let drain. This will insure that the moss is completely wet. (3) Clean seeds and sow on top of moss. Do not cover seeds. (4) Cover flat with a pane of glass or clear plastic and cover the glass with one thickness of newspaper. (5) Place in a light place but not direct sunlight. (6) When seeds begin to sprout, remove newspaper. This should take three to four weeks. Do not remove glass. (7) When plants have three pairs of true leaves, transplant to a flat, that has been thoroughly wet, containing a 50-50 peat moss and sand mixture by volume. Space seedlings one inch apart in rows two inches apart. (8) Grow seedlings in this flat (covered with a pane of glass until plants are established, about two or three weeks) until next spring at which time they should be set out six to eight inches apart and twelve between rows. They can remain here until they bloom.
        Azaleas can be grafted but we have had no experience with this type of propagation and think it not necessary for Evergreen Azaleas.

PESTS AND DISEASES
        Compared to other shrubs Azaleas can be said to be relatively pest free. But if you are bothered by lace bugs, white flies, aphids or leaf miners, treat with Diazinon or Malathion according to directions on container. For scale use Volck or Oil-I-Cide. For weevils and many forms of beetles use Malathion or Chlordane.
        Petal blight, the bane of all Azalea growers, has been controlled in this area by using "Acti-dione RZ" as a ground spray, one month before colored buds appear, and followed by colored bud and open flower spraying as the season progresses. This, or any of the other controls, is a lot of work and most people won't or don't have the time to see that it is done. The hope of all is a systemic fungicide that could be applied once or twice each year.
        Leaf Gall and Leaf Spot can be controlled by using Captan or Ferbam. These must be used early, before buds show color. For Die-back and Branch Gall, all infected parts must be cut out. No other control is known at this time.


Volume 21, Number 4
October 1967

DLA Ejournal Home | QBARS Home | Table of Contents for this issue | Search JARS and other ejournals