Master Rosarian, South Carolina Rose Society
This article is a 2016 Award of Merit winner
Time flies when you are having fun, and this spring blooming season has flown by...but what a great season it was! This spring weather was remarkably good for growing roses. There was no customary late freeze arriving in April and we had a cool spring with no days breaking the 90 degrees mark even once before the roses bloomed. The result was the earliest blooms that we have seen in 37 years of growing roses here; also with the cool weather, we saw huge flowers which bloomed in our garden, most of which had fabulous form with pinpoint centers, and outstanding substance and color, giving us a taste of what our Northern brothers always enjoy and take it for granted. I hope you had similar experiences as well! Our garden came into full bloom three weeks ahead of the usual time of second week in May. Vijaya, my deadheading machine, made short work of the job, literally cutting off two wheel barrows (six cubic ft. each) full of spent blooms every day for three days and had most of the hybrid teas dead headed before our Greater Columbia Rose Society garden tour! Well, it is time to move on to the hot summer, which will no doubt descend upon us in the next couple of days!
The most appropriate bit of horticulture for exhibitors to discuss this month is how to get one’s plants through the summer in the best possible shape so that they will be able to tolerate a light pruning in the latter half of August in preparation for the fall blooming season. There are four important horticultural components to this challenge. The first and most important aid we can give our roses to withstand our hot summers is sound irrigation; one’s soil should be constantly and evenly moist, free of waterlogged areas or dry spots. The second important aid in soil management is to keep the beds totally weed free. Opportunistic weeds will take over generously watered and fertilized beds in a few short weeks. A good layer of mulch will help reduce germination of annual weeds and conserve soil moisture. The third item is to rigorously follow IPM and maintain a preventive spray program for fungal diseases. I will not address the annual assault of Japanese Beetles as the damage caused by them is self-limiting and will not affect our fall blooms. Merit (imidaclorprid, which is not labelled for this purpose) is effective in killing adult beetles and consequently reducing their numbers in your garden the next season; however, they will come from other areas around your garden over which you have no control. The same goes for B.T. (bacillus thuringiensis). Also, avoid beetle traps because they attract beetles from some distance that will end up in your garden! The last and perhaps equally important item is to keep the bushes dead- headed, appropriately thinned out and pruned while retaining an adequate amount of healthy foliage. I will briefly discuss this last item, which could be considered as a sequel to my recent article on pruning which appeared in the spring issue of the Noisette.
When performing mid-season deadheading and pruning, it is well to remember there is not a single rule that covers all rose bushes. Each plant’s individual condition, size and type must be taken into consideration. Let us start with a small bush. When a small bush has finished its spring blooms, irrespective of whether it is a miniature, miniflora, floribunda, a shrub, hybrid tea or climber, it only needs a simple deadheading. That means one only needs to remove spent blooms and nothing more. The idea is that all foliage must be conserved, because these leaves will be working hard, performing photosynthesis to generate energy needed to produce basal breaks, a process which will help the bush grow in size and mature. Additionally, if there is any disease, such as black spot, the infected leaves should be removed and disposed of in plastic bags.
When I see a medium sized bush which is ready for deadheading, in addition to removing spent blooms, I consider what the bush should look like when I am done with that bush. I will cut back longer stems deeper than the first leaf with five leaflets. If I am challenged to give a guide-line, I would say I cut off approximately a half of the stem, which may mean that I might remove one, two or three of those five leaflet leaves. I would also take this opportunity to remove any blind growth tending to crowd the center of the bush. I coined the term “boxwood rose” to describe a bush which is so dense with foliage that you can’t see the grass or other background material beyond the bush through gaps in foliage. When properly done, I ought to be able to “see through” the bush, at least to some extent. Similarly, when I
deadhead a large bush (four feet or taller when the first spring blooms are finished) I take the opportunity to reduce the over-all height of the bush. Thus, on a fortuniana grafted hybrid tea or a miniflora bush, I am likely to cut back most of the length of the stem leaving only about two, three or four five leaflet leaves behind. This helps me control the over-all height of the said bush. In addition to cutting long stems, I
also thin out the growth in the center of the bush to promote air circulation and to ensure spray of fungicides and pesticides reach all foliage for even coverage. Mr.Johnny Becnel, who was one of the original nurserymen who sold and popularized fortuniana-grafted roses shared his experience with pruning and deadheading fortuniana bushes. He said that he leaves no more than the bottom two sets of five-leaflet leaves on each stem that he dead heads. He said that typically, there would be no further new growth from that stem until fall. With this type of deadheading, in the fall, fabulous blooms are produced on new shoots that emerge from the nodes on the canes where the stem originated and not from the point where the stem was pruned.
I saw a video online which was entitled “how and when to prune roses”. The expert explained he would be performing a mid-season pruning of a growing bush. He had a puny looking, potted rose bush which appeared to be about 20 inches tall and wide, with many short stems, three spent blooms and a few leaves, all of which were diseased. He proceeded to remove all “crossing stems” and “dead buds”, cutting each of them back to main stems. He painstakingly showed how to cut above a five-leaflet leaf on each of those short stems and how to cut them at an angle, although not slanting downward, away from the axillary bud. He appeared to be at a loss to find an appropriate “outward pointing bud” to prune above. The poor plant had produced two or three basal breaks of modest size. He proceeded to cut all of them off commenting that “the lower growth must be removed to encourage the top growth”. My best guess is that he was confusing rootstock suckers and basal breaks and thus proceeded to remove basal breaks! The hapless little plant actually only needed its three spent blooms and diseased leaves removed, and a good dose of fertilizers and water. But when he was finished, it looked pitiful and bare of most foliage! It appeared that neither the expert nor the videographer had the necessary knowledge to produce a video on how to do a mid-season rose pruning. To my horror, I saw feedback from several gardeners and or beginners, who said “thank you for this excellent video, which simplifies this complicated topic of pruning roses. I will go out and prune my roses just like you showed how it should be done!”
As we, the C.R.’s and experienced growers began writing and giving programs on this important topic, many new and unnecessary rules were created and pruning practices became very complex, even daunting, especially to beginners. Gradually the pruning pendulum has swung back to its rightful position emphasizing that one cannot harm a rose bush by making a few simple pruning mistakes. Unfortunately, the video I mention earlier, which I am sure has a very wide distribution and will reach a vast number of beginners and encourage them to, yes, remove basal breaks. So I feel compelled to start a list of pruning mistakes one should try to avoid. Number one, obviously, is do not remove basal breaks! The bush will be harmed if you do that, without question!
I think that it would be worth explaining the difference between the suckers from the rootstock and the basal breaks and how to distinguish between the two, so that beginners will not mistakenly remove basal breaks. A good starting point would be to familiarize oneself with the most common rootstocks. Here in the United States, the two most widely used rootstocks are Dr. Huey and the Canadian Multiflora. In the southeast, another popular rootstock is Rosa Fortuniana.
When someone says to you that they had a rose bush which used to produce beautiful, big, yellow roses, mostly one bloom per stem, for several years but this spring, the same plant produced a few bunches of smaller, double red roses and now the plant is growing like a climber with no more blooms rest of the year, it is obvious that the scion, or the grafted top died and the root stock, Dr. Huey is growing! Dr. Huey, by the way, could be a little bit harder than other rootstocks to correctly identify as its foliage can resemble any other common hybrid tea roses. The leaves of Dr. Huey tend to be larger than the leaves of other two rootstocks we will shortly discuss and also have somewhat similar color as the rest of the roses. Canadian Multiflora foliage has distinctly smaller leaves, of light green color and will grow very fast, like a climber. The third kind of rootstock, which has become very popular with Southern exhibitors is Rosa Fortuniana. This rootstock has the reputation for producing widespread, strong root systems and comparatively very large bushes which bear many blooms on longer stems. When suckers emerge from the base of a bush grafted on Fortuniana, they are also of light green color; they grow fast like climbers, with somewhat small leaves and few thorns. Pictures numbered one, two and three show Dr. Huey, Multiflora and Fortuniana respectively. It is good to familiarize oneself with what these rootstocks look like so that the suckers can be identified easily and promptly removed as soon as they appear.
Though sometimes confused with a rootstock sucker, a basal break is generally defined as growth originating from the graft union or a few inches above it. Most basal breaks are red in color, in contrast to the light green color of rootstocks, the exception being Dr. Huey whose foliage is going to be larger than the other rootstock suckers and can be very similar to that of the scion, (the variety you are growing). If a sucker is allowed to grow and mature, removal will then result in even more suckers arising from the same spot, repeatedly, over and over again. There has been some discussion regarding whether tearing off a sucker at the point of union is more effective in preventing re-suckering than cutting it off at that point. In my experience, cleaning up of soil around the point where the sucker originated in order to be able to clearly see it and cutting flush with the trunk is more effective in preventing re-suckering than just yanking it off!
To summarize mid- season deadheading and pruning practices:
1. Remove only spent blooms on small bushes
2. On medium sized bush remove spent blooms. Moderately cut back each stem. And remove blind shoots crowding the center so that you can “see through” the bush.
3. On large bushes, cut the stems deeper so as to keep the bush from getting overly tall by fall.
Also clear up the center, remove dead growth and blind shoots, and remove diseased foliage.
4. Remove all suckers as and when they appear.
5. NEVER remove basal breaks! That is really not good for your bushes!