About Selecting Seedlings
By Ben Lancaster
I have read and re-read with keen interest the discussions on the finer points of rhododendron breeding in The Quarterly Bulletin of the American Rhododendron Society and regard with some envy the background of knowledge shown by the various breeders who have contributed their experiences and theories to improve the hardiness or quality of American hybrids.
Having started my own rhododendron program some fifteen years ago without any special knowledge on the subject, I shall attribute any small success I may achieve to plain luck and what little horse sense I developed along with the other colts on the farm where I grew up. As a farm boy I was taught that superior results in breeding could be expected only from thoroughbred parents. Assuming that this premise would hold true in plant breeding, I proceeded to select the parents of one hundred or More crosses I have made, with due consideration as to hardiness, growth habits, foliage, flower form and color. These parents were always selected with some definite objective in mind as to improvement over the parents, or to create a new form or growth habit which would be more suited for some special environment or situation where we would like to grow them, as in foundation planting, sunny borders or perhaps some shady spot where some favorite fails to thrive. For instance the cross, R. racemosum , R. pemakoense thrives in the shady border in rather close quarters as well as the open rock garden situation that R. pemakoense seems to demand, and was considered attractive enough to receive an award. A plant is in the shady side of the rockery at the Portland test garden at Crystal Springs Lake Island.
It is my considered opinion, that whatever method or theory of rhododendron breeding is favored, be it "shotgun methods with complicated hybrids," line breeding with pure bloods or highly scientific procedure, the most important part of the operation is the selection of the seedlings you wish to inflict on fellow rhododendron lovers.
As for breeding in the iron clad hardiness class, we in the northwest must necessarily leave that work to men like Mr. Gable and others in their more rigorous climates on the eastern seaboard. Personally as a breeder I welcomed the -20 F. at night and -10 F. in daylight hours for the few days it was with us in January of 1950. It eliminated quite a few half hardy seedlings in the open field where we grow them and demonstrated the considerable variation in hardiness in seedling groups.
Our seedling selection for future observation begins when the plants are in their third or fourth year. Any showing unfavorable tendencies have been discarded before this time. This first selection is made for excellence of foliage, habit of growth, vigor, dwarf character or whatever ideal we were striving for when we cheated the bees out of their haphazard job of pollenization.
These plant characteristics we consider in making selections would read about as follows; plant should branch naturally without continuous pinching back to create a well rounded shrub; annual growth stems should be of sturdy caliper and not overly long, 4" to 6" would be ideal for anything except dwarf forms. Slim willowy growing plants that will not support a blooming truss are avoided; foliage may be of any good healthy appearing green, (the darker and finer textured the better as in 'Purple Splendor'); leaves should be as resistant as possible to frost or sunburn under ordinary growing conditions and be retained on the plant for several seasons. We count the annual growth cycles and try to select those which carry their leaves in good condition 4 to 5 years. We have checked many seedlings up to 7 and 8 years that have retained practically every leaf that has grown on the plant. Such plants generally grow slowly and seldom appear leggy. Another growth habit we feel is important is the number of dormant eyes in the leaf axils and how they are spaced along the growth stems. We prefer them spaced near the terminal bud and avoid those with blind eyes (no buds in the leaf axils).
Such characteristics may seem unimportant at first glance but just wait until that vigorous hybrid gets out of hand in a few years. Too big for it's surroundings or to move handily, the only solution some drastic pruning. The ones with these good traits can be reduced to half their size or more, if necessary, over a two year period without sacrificing a year's bloom, if you cut back half of the plant one year and the remaining the following year.
These first selections are made before the plant is of blooming age. Each selection is given a number with parentage noted and grown on under field conditions with no special care until bloomed. When bloomed, colors are checked with the Royal Horticultural color chart and recorded with flower sizes, number to truss and other bloom characteristics. These selections are checked for several years or until the plant is mature enough to produce what we consider it's maximum bloom. Color and type of bloom selection poses many more difficulties than the plant form selections made previously. Colors must be clear and definite, two or more colors in the different parts of a flower are acceptable if they blend well and sometimes are very attractive. Flower must be of good first substance and last well under ordinary conditions.
In our own experience, primary crosses between two species have resulted in colors with very little variation and only slight differences in foliage and habit. For instance: Records on R. griersonianum X macrophyllum (our native northwest species), several bloomed this year for the first time, read as follows:
- Flowers: 3" wide, 1½" long. 5 petaled, wide bell. 15 flowered upright truss. color, spirea red #025/1, top petal slightly freckled darker shade.
- Leaves: 5" to 7" long, 1½" to 2" wide, oblong elliptic. Persistent.
- Habit: upright rounded bush, sturdy growth stems, vigorous grower.
This description as to color and habit would fit any of the dozen plants grown from this cross, that have bloomed to date. Further observation will likely show one or more of the lot superior to the others. I might add that this cross was prompted mainly out of respect for our northwest rhododendron, which we consider a lovely species, when given a chance. Many consider the resultant hybrid a charming plant.
This same constancy in color and form has seemed to hold true in many of our species crosses with named hybrids, for instance; R. griersonianum X R. 'Purple Splendor' has given 12 to 16 flowered trusses with 3½" to 4" flowers of long lasting quality and substance, splendid foliage and growth habits that are nearly identical. Basic colors are rhodomine purple, throat glows of cardinal red, some heavily eyed with garnet brown or deeper. it difficult to choose between them. The R. 'Purple Splendor' X R. 'Tally Ho' cross gave many numbers nearly identical to the R. griersonianum X R. 'Purple Splendor' group in color and habit and others with a slight variation in inflorescence character with very little color variation.
It is in making selections from groups like the foregoing that the little things, as leaf persistence, color and texture and some of the general growth habits are the deciding factors in choosing the ones we feel will be worth while.
We have tried to avoid making crosses with varieties of unknown or complicated parentage, lacking sufficient room to grow the many plants we feel should be tested in order to obtain something good. Even the crosses between primary hybrids have shown considerable variation. R. 'Fabia' X R. 'Tally Ho' has produced some plants of rather dwarf habits, some on the spreading side, others in upright rounded forms. Recorded colors range from majolica yellow, burnt orange, marigold orange, fire red, currant red, signal red, blood red, geranium lake, porcelain rose and various scarlets, many self colored and others in combination of these and other shades. R. 'Fabia' X R. 'Azor' has produced these same color variations with a few added as, peach and various shades of rose. However the influence of R. discolor in the R. 'Azor' cross has given this group a wider variation in growth habits, having produced a few with lots of vigor and larger flowers.
The dozen or more selected forms from these two different crosses between primary hybrids have given us a wide selection of plant form within their color range. Here again the original selection in seeking for plant perfection has materially aided us in making the final choice of seedlings. We would in no way minimize the importance of color and flower character in the selecting or judging of rhododendrons. We just prefer beautiful blooms on beautiful plants. If plant foliage and form was our only aim, we would plant some of the many admirable forms of laurel. We have been greatly aided in confirming our color selections by garden club groups and others, who are doubly welcome to visit Lackamas Gardens and pass judgment on our attempts.
Incidentally, the "we" used by the writer, indicates the better half or silent (?) partner. Growing the plants is my part of the job. Keeping records and color reading is her province. Color classification, using the Horticultural color charts as issued by the British color Council can be highly exasperating at times. The search for that little nuance of shading that will match some luminescent color in a flower part is materially aided by the assistance of two or three color conscious aides. The milder shades are sometimes difficult but easier on the eyes. Recently I made the mistake of presenting four flowers in the so called hot scarlet and red class to the expert at one sitting. I received my classifications and also found out the meaning of that old expression "seeing red."