The Q&A Archives: Rose buds do not open

Question: I have a few rose bushes which were planted last year and flowered well. But this year even though they got big buds they are not opening. The buds have remained tightly closed and have started wilting. The bush is doing good and growing well. What can be done to help the bushes?

Answer: Without seeing the rose buds and carefully inspecting them, it's difficult to make a positive diagnosis. However, the symptoms you describe sound suspiciously like damage from rose weevils (also known as Curculios). Rose weevils make their damage to roses more than one way. Weevils feed on the rose buds and flowers by puncturing and sucking the juices. After that they lay their eggs in those same buds and when the larvae hatch, they feed on the petals and the receptacle area. If any flowers manage to open, you will notice distinct small holes in the petals that were made by the adults. The adults drill small round holes deep into the flower buds and hips for feeding and egg-laying. Eggs are usually laid in the hip or ovary and the small white larvae feed on the reproductive parts. The greatest damage to roses is cause when adults feed on flower buds. The adult punctures the floral parts contained inside buds. Later, if the flowers suceed in opening, these flower parts are riddled with holes, resulting in ragged , unsightly blossoms. If flower buds are not plentiful, the adult weevil may feed on the tips of new rose shoots, causing the death of terminals. At other times it may gouge the stems of buds, causing the bud to wilt and die.

Many species of weevils are resistant to many insecticides. The best thing to do is to hand pick the adult weevils off of the blooms as soon as you see them, then remove the damaged buds and spent blossoms. This will prevent continuing damage minimize the chance of large populations the following year. Make sure that you look for them in other places in the garden too, no just the roses. Adult weevils drop readily from plants and feign death when disturbed. In order to take advantage of this behavior, collect the adult weevils with a wide mouth container half full of soapy water. Touch the plant parts where the weevils are feeding and they readily fall down into the soapy water and drown.

Best wishes with your roses!

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