I have some rose bushes that the petals fall off as soon as they bloom. Anyone know why or what to do to stop?

I have 10 bushes and only three of them do it (they are all tea roses). They are all in the same garden.

I have some rose bushes that the petals fall off as soon as they bloom. Anyone know why or what to do to stop?
Do you have thrips?



Adult thrips are tiny, slender insects, 1/25 inch long, variously colored pale yellow, black or brown. They have four long narrow wings fringed with long hairs and very short legs. Their chief target is the rose bloom, especially the red, white, yellow, and other light colored varieties. Flower thrips and tobacco thrips attack rosebuds and disfigure petals. They attack buds in their early stages, working among the unfurled petals. The buds become deformed and fail to open properly, while the damaged petals turn brown and dry. New growth also may be damaged in the same way.



Since thrips burrow deep between the petals, early identification and control is important. Set out yellow sticky traps about 4 weeks after last frost as early warning devices. As soon as you spot thrips on the trap, spray rose buds with insecticidal soap or a pyrethrin/pyrethrum insecticide product as directed on their labels. Commercially available predatory mites, lacewings, ladybugs and beneficial nematodes are effective backups to the soap spray. Thrips prefer a dry environment, so make sure plants are adequately watered.



Here is a link that discusses the identification and control of thrips: http://www.ipm.ucdavis.edu/PMG/PESTNOTES...



This is the western flower thrip which attacks rose petals: http://www.ipm.ucdavis.edu/PMG/F/I-TS-FO...







Botrytis Blight?



Botrytis is a fungus that attacks rose petals. It is also known as Bud Blight or Flower Blight or Grey (Gray) Mold, and also when the cane is affected: Cane Canker. The first symptom you will probably notice is a characteristic set of pink spots on white and lighter colored blooms. Sometimes there is a pink ring that forms around these spots. These can also appear as yellow or brown flecks as they age. At times this can even look quite artistic. Other main symptoms will be balling of the buds or failure of the buds to open. The petals can then turn brown at the bottoms of the bud like shreds of a paper bag. In serious cases, infected leaves can appear as if they are rotting away. Sometimes there can be a grayish brown fuzzy growth on parts of the infected portions. Lower petals on these blooms dead and brown. A gray mold can also occur at the base of canes that are covered by leaves or mulch. The problem is most severe in humid and cool (60 degrees F) conditions. The disease tends to start high and run down the stem so that over time, more and more of the plant becomes infected. The blight survives winter as black lumps in the soil or on dead infected canes and buds that have not been pruned off.



Treatment: Cut out and destroy all infected plant parts. Also open up the plant so it has good ventilation and air circulation. Preventative spraying isn't very effective, but will work in some climates and cases. Chemical spraying is with copper hydroxide or lime sulpher early in the season.



Spider mites?



This deforms flowers and stunts and deform the foliage. I doub its mites from your description, but Iinclude it because there is a possibility. Many rose gardeners complain that their roses suffer from stunted and malformed flowers and foliage. While there are many conditions that can cause this problem, one of the most common causes is spider mites. These spider mites may be either yellow, red or green, and they cling to the underside of the leaves, where they suck the juices and nutrients from the plant.



While spider mites are certainly a troublesome problem, in many cases the problem can be cured simply by applying a strong stream of water to the foliage to dislodge the mites. If this doesn't work, there are commercial preparations designed to fight such infestations, as well as a number of beneficial insects that can be used as natural predators for these unwanted garden visitors.



Rose Midge?



Roses fail to blossom or existing buds suddenly turn black and die. The foliage and the stem surrounding affected buds may also blacken and die.



Rose midge, a fly larva that is white and 1/12 inch long. The larvae feed in clusters at the bases of rosebuds.



Prune off and destroy all infested plant parts. Spray plants with an secticide and apply a systemic insecticide to the ground around the plants where the larvae pupate.



Final thoughts: I found a web site that lets you ask a question of a consulting Rosarian. All I ask is that you email me their answer when you find out what is the problem - http://www.sdrosesociety.org/menu_ask_ex...