|I have several red carpet roses and three yellow ones from Monrovia.
The red ones, three years old, have not bloomed much this year. What can I do to improve blooming? Can they be transplanted? If so when and how?
The yellow ones, a year old, had black spot. Please help.
|You may be able to move them successfully if you can dig up enough of the root system -- dig as large a rootball as possible. Replant immediately at the same depth as they grew before, water deeply to settle any air pockets, and mulch over the root area. Water as needed to keep the soil moist while they reestablish. This would be a good time to try, or you could do it in very early spring as soon as the soil can be worked.
General considerations with regard to better blooming include a location with full direct sun all day long or a minimum of six hours a day including noon, a site with good air circulation, and soil that is evenly moist yet well drained. These roses also do best if cut back quite short each spring. After several years you may also need to thin out some of the oldest canes. This will improve air and light flowing through the center of the plant.
You might also want to run some basic soil tests and check pH and fertility levels. Your local county extension should be able to help with the soil testing and also with troubleshooting.
Black spot is a fungal infection. Here are some general guidelines you may find helpful.
Unfortunately, many rose varieties have little or no resistance to black spot. Innate susceptibility plus the weather as well as cultural conditions can all contribute to it appearing and to its severity in a given year.
This is a fungal infection. Damp conditions would of course encourage it to develop. Once black spot appears for the season, it is difficult to control. In general, remove affected leaves as soon as they appear and then replace the mulch immediately beneath the plant to try to keep the disease spores from splashing back up onto it. Keep the plant lightly thinned to promote air circulation and make sure it is planted in a location with good air circulation and in enough sun. If you water, avoid watering the foliage and water in the morning rather than at night. Finally, each winter, remove all of the leaves from the plant and dispose of them. Then replace the mulch beneath the plants. Also remove any prunings from the area. These steps should help limit reinfection.
Once you see signs of it developing, you can pick off the affected leaves, and consider spraying. People have reported success using products containing neem oil or containing sulfur (read and follow the label instructions carefully), or using a home-made spray containing one part milk and two to three parts water. Although some people also report success using a baking soda based spray, it can burn the foliage on some sensitive roses and according to the American Rose Society is better as a preventive than a treatment. It is usually a good idea to test spray a few leaves, wait a few days, and make sure there is no adverse reaction prior to spraying the entire plant -- some roses are extremely sensitive to sprays of any kind.
If your plants are in pots, you may also want to spray the pots and surrounding patio or deck to try to keep the spores from splashing back up onto the plants. (Test and make sure the spray will not damage these surfaces.)
Good luck with your roses!