RHA Newsletter 6(3): 8-9 (1975)
Sometimes, roses are reluctant brides. What can be done to ameliorate this reluctance?
In nature, when a plant is in danger of dying, or is in poor health, it will endeavor to reproduce in order to perpetuate the species. It is from here that we take our cue, and that is to make the plant struggle for survival.
Allowing long grass to grow up around the plant and creating competition works in some cases. In one township in New Zealand, I remember seeing just how roses should not be grown. In this case it was a small roadside area someone had evidently tried to tidy up, inasmuch as it was next to a major turnoff. A few roses had been planted in the lawn, and the grass came right up to the stems of the roses, with no cultivated area at all. Under these circumstances, it was safe to assume that the roses received no fertiliser whatsoever and no watering save when it rained. One of these roses was Iceberg, a poor and miserable specimen if ever I have seen one. Normally, Iceberg seldom sets seed; if it does, the seed count is very low. Well, here it was with more hips on it than I have ever seen for this variety, and I very quickly grasped the lesson that it taught me.
Planting in planter bags will restrict the roots and also make life hard for roses, and I have seen Diamond Jubilee setting seed in this manner. There were not many, but nevertheless it was setting seed, whereas in the open garden one never sees a seed pod.
I would like to recommend the reading of an article in the RNRS Annual of 1967. On page 123 is an article by E. F. Allen on the use of gibberellic acid as an aid for making "way out" crosses. I tried this out for one season, and I did get some seedlings from Silver Lining that I wouldn't have obtained without the treatment.
Sometimes it is possible to get open-pollinated seed hips from some of these harder types from areas where a large number of them are planted, such as public gardens. I have noted that some varieties which never set seed on isolated plants will do so in areas where many bushes of the same variety are planted. I am curious about the reason for this and would appreciate theories from other RHA members.
At one of our local rose society meetings, one of our members shoved some slides of the Parnell Rose Garden in Auckland and one was of Frau Karl Druschki. Curiosity got the better of me, as Frau Karl Druschki has a reputation of not setting seed. I wrote to the caretaker of these gardens, asking if his bed of Frau Karl set any hips and, if so, would he mind sending me a quantity of them. Back came the reply and 19 hips, which yielded 240 seeds. Now I am hoping they are fertile and will germinate and amongst them will be one which will set seed that I can use further in a breeding program. Coming from a public garden, they might be crossed by a near neighbour, and only time will tell what traits they will carry. I hope some other members can add ways of making these difficult ones yield seed.
Hints on Improvement
of Seed Set
On Page 17 of the Summer, 1975, Newsletter, Henry Johnson's comments led me to believe that I should pass on some of the things I have learned about getting a rose to accept pollen and deliver a hip.
I used to think that because I was unable to get hips on a variety that that variety was constitutionally unable to produce seed. But I learned two things which I was doing wrong. I was fertilizing too heavily in June, July, and August, and I was emasculating the bloom too soon.
In the Summer Newsletter, I read that several members are emasculating the blooms at one-half to three-fourths open. This is too soon for many varieties. If one waits until the day it is going to open by noon and until he can see a small opening in the center of the bloom, exposing the pistil to view, then it is time to emasculate. Until I started using this method, I thought such varieties as Anne Letts, Tropicana, Kordes Perfecta, Fragrant Cloud, Peace, and a few others would not grow seed. But since I started using this method of timing the emasculation, I can get seed on just about any bloom that has stigmas. But not every one. There are exceptions.
I used to give each plant a cup of fertilizer the first of June, July, and August. And all summer the hips would just keep dropping until harvest time. By then, I had only a few left to harvest. Since changing my fertilizing and emasculation methods, I have been harvesting a full three-gallon pail of hips with their 3-inch stems and labels each fall. My entire fertilizing for the year consists of the following procedure. I use one tablespoon of epsom salts and two of ammonium sulphate two weeks before the first leaves appear in the spring. When the leaves appear, one tablespoon per plant of soluble fertilizer like Rapid-Gro is used. Repeat every 10 days until three weeks before the first blooms. In Detroit, this is the 15th of May. At that time, I give each bush three cups of an organic fertilizer which I mix myself. The mix consists of five pounds of epsom salts, ten pounds of tobacco stems, and fifty pounds each of fish meal, blood meal, cotton seed meal, alfalfa meal, bone meal, and Melorganite. That's all they get until the following year. I keep them watered when they need it.
Drugs to Aid Crossbreeding
It has been shown that the drug which doctors use when they perform a kidney or heart transplant, and wish to insure that the body receiving it does not reject it, can have a use in plant breeding. Apparently the very same drug can prevent the pistils of a flower from rejecting pollen which it would ordinarily know they have no business to flirt with. The name of the drug is Amino-n-Caproic Acid, and it is available in the U.S.A.
How much will this fortunate discovery help the rose breeder? For those who keep to the beaten paths of hybrid teas, floribundas, and the like, it may not do much, but for anyone who wishes to bring in genes of remotely related species which the parent plants would normally regard as foreign, it may be the means of opening new doors. One would guess that its effect in restoring fertility to "mule" plants would be nil.