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Canna

February 1, 2016

QuestionI dug up some Cannas rhizomes last fall and have stored them in the garage this winter.  I wanted to move them to another location.  When should I replant the rhizomes and do I need to do anything special when I replant them.

 

AnswerWait for all chances of frost to pass, then divide the rhizomes and replant in a sunny location where they get plenty of water.  Cannas multiply quickly, so dividing them at planting will allow them room to grow.

 


 

October 24, 2015

Question

This popped up this spring. Any idea what it is?.

 canna beside rock wall

AnswerIt looks like a dark-leafed variety of canna.  We now have folks growing them more for their unusual foliage than their flowers, but I would suspect a dark flower accompanies this one. 


 

(May 2008)

QuestionMy cannas haven't bloomed in three years.  Is it because they are not in full sun? They only have sun in the afternoon?

 

AnswerCannas need a minimum of six hours of sunlight to bloom their best.  They also may be too crowded.  Canna bulbs grow quite quickly and can easily get overcrowded.  Try thinning out the plants and try moving a few to a sunnier locale and see how the blooming goes.  Water well and fertilize two to three times during the season.


(Nov. 2008)

QuestionEvery year now we get something rolling itself up in young canna leaves in our six-year-old canna bed. We've noticed black specks, and the tightly rolled leaves never open, but become lacy. In previous years we've just kept clipping them off as they occur, but this year I'm more aware of butterflies and beneficial insects in all their stages of life. I don't want to be tossing away something that will be a butterfly or be helpful someday. None of the butterfly books I have mention cannas as a host plant. Just to be sure, can you please tell me what affects cannas this way?

 

AnswerThe problem is an insect called the lesser canna leaf roller (Geshna cannalis) and seems to be getting worse all the time.  The adult of this insect is a small, light brown moth.  She lays eggs in groups of 6-15 on the upper surface of the canna leaf starting soon after the cannas have emerged in the spring.  When the eggs hatch, the larvae tunnels into the leaf leaving behind the droppings or frass as they feed.  When they get to be about one week old the larvae initiate the leaf rolling, which helps to protect them from predators and insecticides.  The insects overwinter in a pupal form in the dead canna leaves.  Good sanitation this fall, removing all the old leaves and replacing with a fresh layer of mulch can help you start the season out clean. The moths won't get active until the cannas emerge next spring, but there can be several generations of the insects each season.  If you still see symptoms next season, at the first sign--either leaf rolling or the frass or droppings, spray BT (Bacillus thuriengiensis) into the rolled leaf and the surrounding foliage.  Cutting off heavily damaged leaves and destroying them, is also helpful.


(April 2006)

QuestionMy wife and I recently bought our first home. At the time, it had a handsome flower bed. Not being floral experts, we asked the previous owners how they cared for the plants. One plant needed to be pruned, which we did. The others required no pruning or any other maintenance, we were told. Now, what we believe are elephant ears, and some of the other plants, still show no sign of life. I realize they may be reading the weather better than we, but I wonder if there is more that needs to be done. Would you help us by identifying the plants and suggesting any care or maintenance the plants need?

 

AnswerIn the picture you sent, the main plants you have are elephant ears, cannas and hostas. These are all perennials and should be sprouting within the next couple of weeks. Growth rates vary based on soil temperature. In south Arkansas last week, I was amazed at how much had already begun, while in cooler areas, it is not unusual to see sprouting begin in mid April. Be patient for now. The blooming plants appear to be zinnias--it looks like the Profusion Cherry and White zinnias. These are summer annuals and will need to be replanted. I do think you probably want to incorporate some evergreen shrubs in the landscape so your winter landscape is not so barren. You may need to regroup some of the perennials to make way for shrubs, but this can be done as the plants emerge this spring.


(March 2005)

QuestionLast 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.

 

AnswerThere 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.


 

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