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John Fulton

John Fulton
Former County Extension Director

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In The Backyard

Horticulture columns and tips done on a timely basis

Dig Tender Bulbs Now - from Dave Robson

Posted by John Fulton -

Tender flowering "bulbs" produce some of our most colorful summer blooms. Gladiolus, canna, tuberous begonia and others are commonly grown throughout the U.S.

These plants need special care since freezing kills them. The "bulbs" (in reality tubers, rhizomes and corms, in addition to true bulbs) need to be dug up and stored indoors just like potatoes, onions or carrots. Harvesting these bulbs takes the same care as vegetable harvesting.

While the different flowering plants require different handling techniques (i.e., gladiolus differ from cannas, dahlias and tuberous begonias), they all require the same care in handling.

Gladiolus grow from corms. The corms should be dug once the foliage has matured or after frost. Lift the corms carefully from the ground to avoid losing the small cormels that will be future glads.

Cut the tip an inch above the corms, and cure the corms for two to four weeks in a warm spot with good air circulation. Brush off any dried soil with a soft cloth. Remove the old shriveled corm on the bottom of the new tan one.

Before storing the corms, dust them with an insecticide-fungicide mixture. This will prevent the corms from rotting and will control thrips. Store the corms in onion bags or old nylon stockings hung in a place with a temperature of 35 to 45 F and good air circulation.

Dahlias grow from tubers. Cut dahlia tops back to within three to four inches of the soil after the first frost. Dig carefully to avoid damaging the fleshy roots or breaking off the new eyes. Cure dahlias the same way as glads for one to three days. Keep as much of the soil attached as possible.

Store dahlias in a box or plastic bag, packed with vermiculite, peat moss or wood chips, to prevent drying out. Dahlia tubers should be completely covered and stored at a cool 35 to 45 F.

The tubers should be inspected several times throughout the winter; and, if they start to shrivel, sprinkle the packing material lightly with water. If conditions are too moist and roots start to rot, move the tubers to a drier place and remove rotted portions.

Treat canna roots similar to dahlia. Except, store canna roots upside down in a shallow box. Cannas do not require covering. Hold the roots in 45 to 50 F storage temperatures.

Tuberous begonias should be dug before the first frost. Cut tops back to two inches, and dry the tubers in a frost-free location for two weeks. Store the begonias like dahlias but at a higher temperature–between 45 and 55 F.

Tuberoses should be cut back after frost and their bulbs stored in sand or vermiculite-filled plastic bags at 55 to 60 F.

Peruvian daffodil bulbs should be dug before frost and stored upside down in vermiculite or dry sand. Store these at the same temperature need for tuberoses.

Check your bulbs, tubers, corms and roots throughout the storage season, and make any necessary changes in their conditions so that they will make it through the winter in good shape.

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