It is nearly time to store our summer flowering bulbs such as tuberous begonias, dahlias and gladiolas for the winter. Unfortunately these lovely bulbs cannot survive our winters outdoors in the garden.
After a truly hard frost has knocked the life out of the foliage of these bulbs, I dig them carefully out of the ground. You will be amazed at the growth your bulbs have put on over the summer! Cut the foliage away from the bulbs (such foliage makes great compost!) and knock as much soil as possible off the bulbs. Let them sit for a couple of days on your porch or deck until all the soil can be easily rubbed off.
(Glad corm picture from Plants Unlimited)
Dahlias and glads in particular will have added to the parent bulbs over the summer. By that I mean that the dahlia tubers will have added new tubers and the gladiola corms will have added new corms to the parent corm. Feel free to break off these new additions; they will mean more plants next year! Tuberous begonias will have almost doubled in size. There is really nothing to divide but in a situation where you may have had 4 or 5 begonia tubers in one container for 2010 this means for 2011 in the same container you can probably have 3 begonia tubers and still have the same showy look. This means more containers of beautiful tuberous begonias next year.
Winter storage of these bulbs should have 3 goals:
(1) Treat the bulbs for any mildew or little bugs they might have now. Bulbs are living creatures; mildew can reside on them or tiny bugs called thrips can also call your bulbs home. We recommend a product such as Garden Dust by Bonide. I put some dust in a plastic bag and place some bulbs in that bag. Close the bag and shake it well; this dust will cover the bulbs and help get rid of mildew and pesky little bugs such as thrips.
(2) Prevent the bulbs from freezing. The bulbs should be stored in a situation where the winter temperatures are cool—between 40 and 50 degrees. I have an unheated crawl space under my house that works well. Most people have heated basements that may well be too warm. I have heard of people digging a hole about 18” deep outside next to their foundation where the temperature hovers just above the freezing mark.(I have not tried this method myself). Some people have cool basement corners and store their bulbs against the cool basement walls.
(3) Prevent the bulbs from dehydrating. I store my bulbs nestled in some loose good quality potting soil or peat moss in the same plastic bags that I shook them with the Garden Dust. Once I have the bulbs snuggled in with the soil or peat moss, I tie up the bag and wish them a good winter’s sleep. A "zip loc" baggie works great as well!
In late February, it will be time to wake the tuberous begonias and pot them in fresh soil. They will have to stay indoors near a sunny window until the danger of hard frost is past in the Spring. “Ditto” for the dahlias except I would plan on starting them in early March. The glads can be started indoors in mid April.
One final note about bulbs! We have a great selection of fall bulbs like tulips, daffodils, crocus, alliums, fritillaria and more here at Skillin’s! These Spring flowering bulbs are planted in the fall!
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