SPRING PLANTED “BULBS” FOR SUMMER COLOR
“Bulb” generally covers true bulbs and other structures such as corms, tubers, tuberous roots and stems, and rhizomes that store food for the plants. Buy bulbs early to get the biggest selection and healthiest bulbs - usually, the bigger, firmer the bulb, the better the flowers.
There are many spring planted bulbs that provide great color, foliage, and flowers for the summer season. Dahlias, caladium, canna, gladiolus, allium, tuberous begonia, and lilies are some of the easiest to find summer blooming bulbs.
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| Colorado Master Gardener Gail Wilson |
Gladiolus come in nearly every color, including lime green. Plant 3” deep and 6” apart after danger of frost has passed. During the growing season, the original corm withers and a new corm forms on top of it. You can cut the flowers; just be sure the leaves stay until they die down naturally. The remove the withered corm and store the new corms in a frost-free place.
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| Dahlia - CSU Stock Photo |
Dahlias come in a wide range of flower and plant sizes, and nearly every color, except a true blue. Dahlias do not tolerate frost at all, so wait to plant until all possibility for frost is past. They often need support because of their height, so drive a stake 12” deep and 6” behind the root while planting. After the vegetation is killed by frost, prune back the stalks to 6” and leave the tuberous roots in the ground for two weeks to harden before digging. Dig carefully so the tuberous roots do not break away from the clump. Dry the tuberous roots enough to shake off excess soil, and pack in sawdust, perlite or vermiculite and store in a cool, dry place until spring.
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| Courtesy Pixabay |
Canna flowers bloom in a wide range of colors—ivory, yellow, scarlet, salmon, rose and orange. Foliage can be green, bronze or variegated and just as interesting as the flowers. Canna plants thrive in containers, planting beds and also ponds and water gardens. Plant the rhizomes 6” deep and 18” apart in late spring and after the danger of frost has passed. After frost kills the foliage in fall, dig and store the roots over winter, much the same as dahlias.
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| Colorado Master Gardener Barb Kett |
Tuberous begonias range in color from white, yellow and orange to deep red and bloom for long periods. Plant the roots (which may be up to 1 ½” in diameter) 4” deep in a partially-shaded area. Tuberous begonias do best in relatively moist soil with high organic matter. After frost, dig the roots from the ground, pack in sawdust, and store under cool, but frost-free conditions for replanting in the spring.
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| Courtesy Esty |
Allium is a member of the onion family, but these plants are very ornamental and showy. Plants vary in height, and flowers can range from two to ten inches in diameter. Allium flowers are ball-shaped and consist of many tiny florets in hues of white, yellow and blue. Alliums make great cut flowers that last for a long time; flower heads can also be left to dry on the plant and later cut for dried arrangements. While alliums do not need to be dug from the ground after frost, be sure to mulch the bulbs well to ensure winter survival.
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| Courtesy Michigan Bulb Co. |
Caladiums are grown for their foliage which can be white, pink, red or green. These plants do best in shady areas or containers and prefer a highly organic, moist growing medium. After a killing frost, dig up these tubers and store them in a cool, dry place until next spring.
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| Lily - CSU Stock Photo |
Lilies are available in several types and in colors ranging from white and yellow to deep red. While lilies are perennial, some do not survive Colorado’s winters. To test hardiness of a particular lily, dig a portion of the plants and pack the rhizomes in sawdust, perlite or vermiculite. Store the rhizomes in a frost-free location during the winter. Replant the stored lilies in the spring. Any plants remaining in the garden should be heavily mulched to avoid winter kill. Plant the lilies to a depth three times the height of the bulb. Easter lilies can also be planted into Colorado gardens with varied success.
For lots more information on site selection, and soil prep: CSU-FactSheet,