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Friday - August 17, 2007

From: Pflugerville, TX
Region: Southwest
Topic: Non-Natives, Pruning
Title: Deadheading cannas and geraniums
Answered by: Barbara Medford

QUESTION:

I'm new to gardening. Your help would be appreciated. 1) I think I read that canna flowers can be deadheaded so they will continue to bloom throughout the summer. What part is actually taken off? There is a round green pod that grows directly below the blooms. Does this get cut off along with the wilted blooms? What about the stem that remains above the leaves? 2) Can geraniums be deadheaded as well? Do I just take off the wilted blooms, or can I cut the stems off as well. Thank you so much for your help!

ANSWER:

We are assuming that the cannas you are raising as ornamentals are hybridized plants, bred for spectacular color. The entire genus of Canna is native to tropical and subtropical regions of North and South America, with some in southern South Carolina and southern Texas. The native Canna glauca (maraca amarilla) is not nearly as spectacular as the hybrids available in commerce, but a lovely plant, nevertheless. In response to your question on deadheading, this website on cannas (or canna lilies, although they are not true lilies) will give you lots of information on care of these colorful plants. The bright-colored "petals" that you see are not actually part of the blossom, which is small and insignificant looking. The "flowers" are actually staminodes and Nature's intention in creating the bright colors was to attract pollinators who collect nectar and pollen. According to the information we were able to find, it is always good to cut back the entire stalk on which a flower has faded. It is such a vigorous plant that the stalk will quickly be replaced by a new one with new blooms on it.

In response to your second question about deadheading geraniums, we have another question: "Which geranium?" As you know, the Lady Bird Johnson Wildflower Center is dedicated to promoting the care and preservation of native wildflowers, so we will deal first with the perennial natives that you might have in your garden in Texas: Geranium caespitosum (pineywoods geranium) , Geranium carolinianum (Carolina geranium) , and Geranium texanum (Texas geranium). These are all Geraniaceae (Geranium family). They would certainly benefit from deadheading, and it would contribute to more blooming.

It is more likely, however, that you are asking about members of the genus Pelargonium, for which "geranium" is the common name. These are subtropical in origin and, like the cannas, have been heavily hybridized in commerce. They are often used in pots for decorative purposes, and should be treated as annuals. Certainly remove blossoms that have begun to fade and dry, taking off the stem to the next joint. They can be broken off, but are better snipped with garden scissors. And snap off any dead leaves at the same time.

Canna glauca

Geranium caespitosum