Summer bulb plants, including calla lily, canna, dahlia, caladium, elephant ear, gladiolus, and tuberous begonia, boast beautiful flowers and foliage throughout the summer months. These plants grow from fleshy structures such as bulbs, rhizomes, tubers, or corms, but all are collectively referred to as just “tender bulbs”. While they are beautiful during the growing season, tender bulbs will not survive the winter unless they are given proper care and attention. Follow these 4 simple steps to winterize your tender bulbs and enjoy their summer show year after year!
1. Dig up your bulbs
Once the foliage begins to dry or is killed by the first light frost, it is time to dig up your tender bulbs and prepare them for winter storage. It is important to dig them before the first hard frost hits in order to avoid frost damage to the bulb zone below ground. Using a spade or fork, gently loosen the soil several inches back from the base of each plant. Take care to avoid piercing or damaging the bulbs.
2. Remove excess soil
After your bulbs have been dug from the ground, shake each plant to remove excess soil. All foliage can then be cut back 2-3 inches from the bulb head. Gently rinse remaining dirt from your bulbs with a garden hose. Use caution to avoid breaking the outer skin layer of each bulb head; injured bulbs are prone to disease and rot.
3. Cure your bulbs
Most bulbs require a short drying time before they are packed away for storage. After cleaning, set your bulbs out in a dry, well-ventilated space out of direct sunlight (such as a garage or garden shed). Dahlias, callas, and caladiums will dry out in about 3 days. Cannas and gladiolus require a 3 week drying period.
Before packing them away for storage, inspect each bulb for disease or insect damage. Your bulbs may benefit from a light dusting of fungicide as a preventive measure against rot. Wrap each bulb in newspaper or place them individually in paper bags with labels. Include sphagnum moss, sawdust, vermiculite, or coconut coir to absorb moisture and prevent bulbs from touching each other directly. You may also layer your bulbs in a cardboard box, alternating between several inches of one of the above-mentioned natural materials. Bulbs in direct contact with each other may encourage the spread of rot and disease. Do not place your bulbs in airtight containers as this will encourage moisture accumulation. Store the bulbs in a cool dry location (such as a root cellar, basement, or unheated garage) with a temperature between 35 and 50 degrees. Check your bulbs periodically throughout the winter and inspect for signs of rot. Discard spoiled bulbs before they infect the entire collection.