Question: I have 13 rose bushes in my backyard against the side concrete wall that were planted two years ago. The first and second years they really grew and blossomed nicely. But this year, for whatever reason, all the petals are dropping off and most of the bushes are now bare. Because of the warm weather this winter, they seem to have bloomed much earlier than usual (in March). I am wondering if they will have a second blooming season this year before โwinter,โ and what could be causing the petals to fall off. They are very delicate, it seems.
Answer:ย A common problem with most plants is lack of water. Plants often lose parts when they are too dry, and yours are most likely receiving additional heat radiation from the wall. Roses typically require water every three to five days in the summer, every five to seven days in the spring and fall, and every 14 to 21 days in the winter. And you should be watering to a depth of 18 to 24 inches.
Roses also need to be fertilized. It is better to apply small amounts of a slow-release fertilizer every six weeks during the growing season rather than a heavy application once a year. The first application of slow-release fertilizer should be applied after the roses have been pruned in January or February and repeated every six weeks until June.
March is about right for roses to begin blooming in Tucson if you pruned them in late January. At our office, the Rose Demonstration Garden maintained by the master gardeners started blooming in late March and bloomed into April. Some of them are still blooming. Yours will likely have a second bloom in the fall if you prune them again in mid-September. For more details, check out our publication available on the Internet by searching for โroses AZ1305โ with a search engine.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed toย plwarren@cals.arizona.edu.
