Tips for Organic Rose Gardens

"Worms" in Rose Canes/Stems
A number of insect species have larvae that are grouped under the umbrella term "rose borer". These larvae are usually grayish white or yellowish moth larvae that may grow to about one inch in length. They crawl up the outside of the rose canes, then enter the canes through the pruned tips or through other wounds. Some species create their own entry holes in new green growth. The caterpillars (larvae) live in the pith and soft tissue inside the rose cane, and the resulting scar tissue usually kills the entire cane. You will typically see a bulge or swelling on the cane where the larvae are feeding. The bulge is scar tissue that develops in the cane in response to the larval damage. Prune off the cane below the bulge and destroy it. Treat the cut tip of the cane by applying a layer of ordinary white glue to seal it. Buds below the cut should begin to grow soon after the pruning.

When you find rose borers in one rose bush, check your other roses for signs of these caterpillars. Prune them out as soon as possible. You may notice withered leaves at the tops of canes or other signs of stress before you notice the bulge of scar tissue.

Best Fertilizer for Roses
Compost is the best thing you can add to the soil in your rose garden. Besides nutrients and trace elements, it adds humus and improves the general condition of the soil. If your compost is high in nitrogen from lots of green waste content, such as grass clippings, mix in some bone meal to increase the phosphorus level. Phosphorus encourages flowering. Potassium, or potash, is readily available to organic gardeners as wood ashes. Sprinkle sifted wood ashes into the compost pile to incorporate it. Potassium encourages the development of good root systems.

Remember that compost should be completely finished before you use it around growing plants. Incomplete compost can actually drain nutrients from the soil. Plant matter requires nitrogen to break down. If unfinished compost is mixed into the soil around your roses, it will pull the nitrogen it needs from the soil to complete the decomposition process, robbing your rose bush of the nitrogen. Finished compost should look like dark, soft loam soil. It should have a clean compost smell, never an unpleasant odor. While an occasional twig is acceptable, compost should not contain chunks of undecayed matter.

Roses are such heavy feeders that you may need to add supplemental organic fertilizer if you don't have enough compost. Commercial organic fertilizer for roses should have a ratio of 5-10-5 or 10-20-10 for best flowering results.

Source:
Personal Experience