Tender, Summer Flowering Bulbs for Nebraska Gardens

In any discussion of ‘bulb’ plants, the most important distinction to make is between hardy and tender bulbs.  Hardy bulbs, including tulip, daffodil, crocus, etc., are planted in the fall and can be overwintered in the ground.  Tender bulbs, like gladiola, dahlia and canna, are planted in the spring and must be dug up each fall; they are not cold tolerant enough to survive in the ground during winter. 

Many tender bulbs are available at garden centers in spring, ready for planting.

But not all ‘bulb’ plants are grown from true bulbs.  Some grow from rhizomes (Canna), corms (Gladiolus), or tuberous roots (Dahlia). Botanically, there is a difference, but this is generally important only to the horticulturist. The everyday usage of the term “bulb” includes all plants that grow from fleshy underground storage organs.  Regardless of the terminology, summer flowering bulbs are a great way to add a splash of color to the landscape. 

Canna
Cannas are a tropical plant with large spade-shaped leaves and bright red, pink, orange, white or yellow-colored flowers.  Canna height ranges from 2 ½ to 3 feet for dwarf varieties, to 6-8 feet for the standard varieties. 

Cannas grow from rhizomes, or underground stems, which can be started in pots in mid-March then moved out to the garden after danger of frost is past.  The rhizomes can also be planted directly in the garden in mid-May, in an area with well-drained soil and full sun.  Fertilize the plants once a month after growth starts and remove flowers as they begin to fade to encourage further flowering. 

Once frost has killed the top growth in fall, cut off the foliage and dig up the rhizomes.  Brush soil off the rhizomes and store them at 45 to 50 degrees F. Do not allow the rhizomes to freeze.

Gladiola
Gladiolas are a very easy flower to grow, making them perfect for the beginning gardener.  They make a great background plant for the garden, at a height of 1-5 feet tall depending on the cultivar you choose. 

Gladiolas grow from corms, which produce one flower stalk each.  For the best effect, plant the corms in odd-numbered groups of 5-7, 6 inches apart, and 4-5 inches deep.  Plantings of single corms are less effective than groups for color and flair.  They prefer full sun and well-drained soil.  Staking may be needed for tall varieties. 

Dig up the corms in late fall. Remove the soil, air dry the corms and store them at 35 to 40 degrees F.

Dahlia
Dahlias can add BIG color to the garden on 2-8′ plants, with 8-12″ wide flowers in all the bright colors of the rainbow except blue.  Again, tall plants, especially those with equally large flowers, usually need staking to stay standing tall. 

Choose a sunny area with well-drained soil and start the tubers or seed directly in the garden mid-May.  Feed lightly at first because heavy feedings may delay flowering. Prune side stems allowing only one main stem.  Mulch plants after establishment to keep soil cool and preserve moisture.

Tubers must be dug and stored each fall in sawdust or peat at 60 degrees F. Divide the tuber clump in spring leaving a part of the true stem attached to the tuber.  One interesting cultivar is ‘Bishop’s Children’ which has single and semi-double flowers in red, orange, yellow, pink, purple and bicolor, 3-4 inches across, with dark maroon-black foliage.  Height 2 ½-3 feet.

Images from Pixabay.com.