Insects - Leaf Rollers
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  (March) Last year all my Canna Lilies had some kind of worms that caused the leaves not to open. Are the tubers left from last year still infected, should they be destroyed, or, is there a chemical I can use to control the problem this year?

  There is an insect called a leaf roller that can keep the leaves rolled up tight. Cleaning up the spent foliage from last season, may help cut down on the problem this season, since the insects often over winter in the old foliage and mulch. Make sure all the old foliage and mulch are removed and monitor the plants closely for signs of problems. Spray if you see a problem beginning. BT - Bacillus thuriengiensis, Dipel, or Sevin can help, but hopefully, won't be needed.

  (March) I have a long narrow bed in which I have grown cannas in one end, ginger lilies in the other, for many years. I cut everything back to the ground after the foliage has died. I have occasionally dug the tubers and separated them, but most years they just stay in the ground for the winter. For the last several years I have had worms that infest the cannas and keep the leaves tightly rolled. My local nursery people have told me to treat them with Sevin dust, after they manifest themselves. The worms don't bother the ginger lilies. Is there any way to rid myself of the worms permanently so they don't reinfest my cannas every year? Also, would you please give me a recommendation for a fertilizer program.

  Cutting back the spent foliage and removing it is very important. The canna leaf rollers do overwinter in plant debris, so sanitation is important. If you continue to get them, you may want to use a preventative insecticide. Sevin or the BT should work when you see them. Interestingly enough, cannas should be dug and divided every spring--let them make it through the winter intact. Probably most people don't divide annually, but they multiply rapidly, and often don't have as good a bloom the second or third season if not divided--they get so crowded, that they grow taller and have smaller flower heads. Fertilize as they begin to grow in the spring, and then again about six to eight weeks later with any high nitrogen or complete fertilizer.

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