Gardening Tips and Highlights Waushara County Master Gardeners

Saving summer bulbs: Dahlia and Gladioli

Digging the tubers in the fall, storing them over winter, and then planting them to experience their joyful return is a garden ritual I enjoy. I find dahlias to be the easiest of the tender bulbs (and tubers) to save from year to year. I lose a few, but most make it.

The first frost will blacken the foliage of the tender dahlia. After this happens, cut off all but two to three inches of the foliage and carefully dig up the tubers, much like you would potatoes, excavating well away from bulbs and then digging and sifting through the dirt to locate them.

Let the tubers dry for three days in a cool location and out of direct sunlight. When they are dry, tap off any excess soil. I have had great luck storing my tubers in paper grocery bags. I lay the bag on its side, place the tubers in a single layer, and then loosely roll up the top of the sack, just enough to close it with space for a little air to get in. Ideal storage temperatures range from 45 to 55 degrees. You may want to check your stored tubers a couple of times throughout the winter and remove any that have rotted.

At planting time in the spring, you may see some new growth on the tubers, which is encouraging, but even if you don’t see any, the bulb will sprout if it is firm to the touch. Dispose of the dried-up or rotted bulbs, and plant the firm ones about three-inches deep in a sunny, well-drained location. The old stem shows which side goes up.

Just remember, dahlias are heavy feeders and require fertilizing and regular watering to be at their best. The process for gladioli is nearly the same as dahlias except you need to let the corms dry for two to three weeks to cure them before packing them away for the winter. A temperature of 45 to 50 degrees is best for storage, so the refrigerator works well.

This information was obtained from the Northern Gardener at