Hybrid tea or rootstock suckers – What is it: Following a very cold winter, in the spring my roses were killed all the way to the ground. I then notice a few strong, vigorous green shoots coming up from the ground. How do I tell if they are a hybrid tea variety or what is called a sucker?
Answer: There are two ways to determine whether the new growth is a sucker or a named variety. One way is to wait and see how it flowers. Normally hybrid teas are grafted onto wild rose roots that are very vigorous. The flowers on a sucker would be nothing like a large flowered rose. Another way is to determine whether the shoot is growing from above or below the graft union. The graft is the large knob at the base of the plant. If the shoot is emerging from below the graft union, it is a sucker. The named rose should produce all growth from the graft area. If the shoots are suckers, it is best to remove the plant and replant if roses are the plant of choice.
Thrips on roses: I have had a problem with some of my rose blossoms not opening this spring. A nice bud forms and starts to open, but then it stops and turns brown. Is this caused by an insect or disease?
Answer: It sounds like your rose blossoms were attacked by thrips. Thrips are small insects that are sometimes hard to find because they are harbored in the buds of many flowering plants. Their feeding results in the buds not opening as you described. Thrips are hard to control because they are inside the bud where chemical sprays cannot reach them. Products such as Orthene, Sevin and Malathion provide some benefit. Make two to three applications at three to five day intervals for best control.