By Donnetta Wilhelm, Colorado Master Gardener
I loved helping in my ‘Grandmother’s garden’, and she was an authority at growing dahlia, gladiolus, and begonia—all the old-fashioned, summer-blooming bulbs. Summer blooming bulbs burst forth in beauty after many of her annuals succumbed to the hot summer days. ‘Grandmother’s gardens’ were actually the informal, mixed flower gardens that arose in the late 1800s as a reaction against the Victorian ‘carpet bedding’ style. Today, says Leonard Perry of the University of Vermont, most people are so busy they “strive for simpler gardens,” but as some gardeners “add more flowers for pollinators, or combine flowers with edible herbs and vegetables, they are beginning to recreate gardens that hearken back to this old-fashioned garden style.”
These summer blooming bulbs*, magnificent and beautiful in the hot summer days, are damaged by frost and need to be stored in milder temperatures over the harsh Colorado winters. After the first 32°F autumn frost, cut the foliage back to 4-6 inches. Use a trowel or small garden fork to gently dig up each bulb from underneath to avoid damaging them, as damaged bulbs will rot in storage. Loosen soil from around the bulb and lift it out. Lightly brush off any soil and allow the bulbs to cure in a cool, dry place. Always make sure to label them with plant tags.
A great place to keep bulbs in the winter is surrounded by layers of shredded paper in a cardboard box. Assure the storage container is not airtight as bulbs need air circulation to avoid rotting. Store at 45°F (caladium at 60°F, begonia at 50°F), and check them periodically during the winter months for dehydration and dispose of any with rot. In the spring after the soil has warmed, divide bulbs before planting.
More information on summer blooming bulbs can be seen here.
*Note that ‘bulb’ refers to corms (Gladiolus, Crocosmia), tubers (Dahlia, Begonia, Caladium), rhizomes (Canna) and bulbs (Lily).