Growing Green: Spring Planted Bulbs for Summer Blooms
I can’t imagine a garden without the lovely fragrance of Acidanthera (Peacock Orchid). A type of gladiola, the acidanthera flower is a white bloom with a maroon blotchy center, and like the gladiola, is a summer bulb.
Summer bulbs and tubers are planted after the last frost date, once the ground has warmed a bit. In our area, this means planting will take place roughly from mid-May – June. Gladiolas, dahlias, calla lilies, canna lilies and tuberous begonias are all planted in the spring for summer bloom. Some of these are tubers and corms, but for purposes of planting and storing, they tend to be grouped together under the term “Summer Bulbs”. These plants are not winter hardy, so they need to be lifted and stored in the fall before the ground freezes. If you’d like to try summer bulbs this year, be sure to keep these basics in mind.
Summer bulbs prefer well drained soil. Amend the soil with organic matter, such as compost, composted manure or peat moss if needed. Bulbs are to be planted at a depth of about three times their height. (Check the package for specific bulb depths.) Make sure you place bulbs in the ground correctly. Bulbs and corms are planted sprout side up, tubers are planted horizontally. Summer bulbs like moist soil, so water immediately after planting, and keep the soil moist while they sprout. As always, keep your garden weed free. Weeds compete with your plants for nutrients and moisture. Once all your plants have broken the soil, mulch your garden, sit back and enjoy the blooms, fragrances and textures.
After the leaves of tender bulbs have been killed by frost, harvest the bulbs for winter storage. Lift your bulbs with a garden fork, shake off the extra soil, and air dry for several days. Bulbs should be stored in a well-ventilated, cool, and dry location. I generally place my bulbs in a paper bag with a little peat moss and place them on a basement shelf until spring. Mesh vegetable bags also store bulbs well. Don’t store your bulbs in an air tight plastic container because this will retain moisture and encourage mold and rot. Remember to label your bulbs by type and color for easy identification the following spring.
Mixed with annuals, summer bulbs are a striking addition to your container plantings. Plant them close together to fill the container quickly. Canna lilies are wonderful container plants for blooms and foliage. Tuberous begonias, calla lilies and caladium also make great container plantings.
Try summer bulbs this year for a touch of the tropics in your yard.
Robin Trott is a Horticulture Educator with University of Minnesota Extension.