Annuals Gardening Light Needs of Plants

Pale Growth on an Overwintering Annual

Cuphea suffering from etiolation. Photo: Rachel Bernier

Question: I’m overwintering a cuphea Vermillionaire on my windowsill after a friend tried this last year with success. But I find its growth weak and pale, even if it is placed in my sunniest window. Should I prune it back regularly to strengthen its stems?

Rachel Bernier

Answer: The appearance of your Cuphea Vermillionaire® plant shows it simply lacks light, which explains why it is etiolated (showing weak, pale growth).

Honestly, that’s a pretty normal situation for an overwintering annual. Due to the short days and, in many climates, persistent gray weather, fall and winter sunlight is far less than the plant really needs, even in the brightest window, so it etiolates: stretches as if to try and grab a bit more sunlight. By cutting it back, you’ll at least keep it fairly compact until days lengthen.

And, of course, they will. You should notice a huge change in the plant’s growth in starting in March and early April. Its new stems will be shorter and its foliage denser and greener. In fact, as spring progresses, it will probably start blooming again to a certain degree, although not as heavily it will outdoors (indoor sunlight is never as intense as sunlight outdoors).

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The appearance of Cuphea Vermillionaire outdoors in full sun. Photo: http://www.provenwinners.com

When there is no more risk of frost, acclimatize your cuphea to outdoor conditions and give it full outdoor sun. In no time it will again be as gorgeous as it ever was!

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

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