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In My Garden Blog

September 25, 2008
New England
By Kathy Bond Borie,
Richmond, Vermont

Save your favorite glads by storing the corms in a frost-free place over the winter.

Overwintering Tender Plants

The brilliant colors of fall have exploded in the past week. Tawny ornamental grasses, red sumacs and maples, and purple fall asters grab my attention and almost make me forget the summer stars of the garden. But wait, there are still lots of annuals and summer bulbs in colorful garb -- coleus, dahlias, gladiolus, crocosmias, acidanthera, geraniums. Although in more modest dress, the tender salvias and ornamental oregano are still in leaf. I could leave all of them to die with the deep freeze and start with new plants next year. But keeping them through the winter is relatively easy, and the cost savings can be considerable. Plus the longer the potted plants grow, the larger the plant, and the better the show. Many can share our living quarters, others need a cool spot to rest. If you have any of these plants and would like to keep them safe and sound until next year, here are some guidelines.

Gladiolus, Crocosmias, and Acidanthera
When they have finished flowering or when frost kills the foliage, carefully dig the corms of gladiolus, crocosmias, and acidanthera and spread them out in a dry, well-ventilated area at room temperature for two to three weeks. Then remove and discard the old corms. Store the new corms in paper bags in a 35- to 40-degree location.

Cannas
After the foliage has been damaged by frost, allow cannas to dry in the ground for a few days, then cut back the stems to 3 to 4 inches and carefully dig the rhizomes and let them dry at room temperature for a few days. Store in cardboard boxes or mesh bags filled with vermiculite or peat moss at 40 to 50 degrees for the winter. In spring, plant the entire clump or separate the rhizomes, leaving a portion of the old stem attached to each one.

Geraniums
You can keep geraniums growing and blooming indoors by cutting them back by about a third and then starting to fertilize them a couple of weeks later. Keep plants in a sunny window. Or to keep them dormant for the winter, move the potted plants into a dark, cool (40 to 50 degrees) location. Don't water them and don't cut them back until they show new growth in spring.

Coleus
Take cuttings from non-woody stems and root them indoors in water. If you want to save the entire plant, bring it indoors now and cut back the stems a few inches to remove the most succulent growth, which is most susceptible to aphids.

Fuchsias and Tender Salvias
Bring plants indoors now and cut back stems by about half. Keep them in a state of semi-dormancy by moving them to an unheated basement or a place with low light where temperatures stay between 40 and 55 degrees. Water about once a month. When temperatures reach the 60s in spring, move them outside to a shady spot, give the plants a trim, and begin watering and fertilizing.

My friend Andy - who has a greenhouse for vegetables and herbs in
Bend, Oregon- has an aunt named Frances Borie in Philadelphia. Any
relation?
Charlotte

I have an agapanthus x monmid (Midknight blue) which is re blooming
in my garden on Martha's Vineyard, said to be Zone 6A.  Should I dig
it up and put it in a pot in the basement, or should I mulch it and
leave it where it is?  And if I should dig it up, when do I do this?
 Help!  Thanks so very much.

Lee,

Since agapanthus are rated as hardy only to zone 7, it would be
risky to leave it in the ground over the winter. If you surrounded
it with a thick layer of hay or straw, it might survive, but if you
don't want to take chances, bring it into a cool but frost-free
place for the winter and let it go dormant. The cold weather should
be signaling the plant to slow down and go dormant. Withholding
water can help, too. Before the temperatures dip into the 30s, pot
it up and bring it in. Good luck. 

Thanks very much.  I'll put it in the basement and keep my fingers
crossed.  Appreciate your answer, and especially its promptness!

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