Article and Photography by
Master Gardener Judy Stevens
Tulips in bloom mean spring has arrived in Iowa. Tulips, daffodils, hyacinths and crocus are among the most common hardy bulb plants for our area. But these springtime beauties aren’t the only “bulb” plants that grace Iowa gardens.
The term “bulb” plant includes any plant that grows from a bulb, tuberous root, corm or rhizome. Hardy bulb plants stay in the ground in Iowa because they require cold winter temperatures for their growth cycle. That’s why spring bulbs are planted in the fall. Hardy bulbs are relatively maintenance free once planted properly and will reward you with blooms each Spring.
Plan to plant spring bulbs in late October. Select a sunny spot with well draining soil. Bulbs will rot in wet soil. Plant bulbs at a depth equal to three times the bulb’s diameter, about 6-8 inches deep for daffodils and tulips and 3-4 inches deep for crocuses. A less common hardy spring blooming bulb is one of my favorites, the Allium. These are fun plants and look a bit like a big purple “lolipop.” They range in size depending on the variety. Plus they are deer resistant.
Lilies are also hardy bulbs in Iowa and are a terrific addition to any garden. Lilies offer lots of color options and can be early, mid-season or late blooming. Asiatic and Oriental are the most common lilies. The Asiatic are the easiest to grow, they’re hardy and don’t require staking. The Oriental are usually larger and do require staking, and these exotic looking flowers are very fragrant.
Lilies can be planted in either spring or early fall. They grow best in full sunlight, but some varieties like Martagons and Turk’s Cap will tolerate some shade. Mulch newly planted lily bulbs for winter. Established lily bulbs don’t require additional winter protection.
Iowa’s hardiness zone ranges from 4 to 5, which means lots of bulb plants are tender here, needing to be dug up and wintered over inside. These include Cannas, Callas, Gladiolus, Dahlia and Tuberous Begonias.
Cannas grow from rhizomes and are native to tropical areas. They’re very showy, ranging from 2 feet to over 5 feet tall depending on the variety. They have beautiful foliage and large leaves that can be green, dark red or bronze. They flower at the top in a variety of colors. Cannas, like most tender bulbs can be planted directly in the ground in the spring after the soil has warmed and any threat of frost has passed. They can also be started indoors in pots and transplanted outside after temperatures have warmed. Cannas like full sun and hot weather. The rhizomes need to be dug up after a frost has blackened the foliage. Carefully dig them in the fall, cutting the stems back to about 2 inches and let them dry. Once dry store in a cardboard box in a cool location where they won’t freeze.
Callas are sometimes confused by name with Cannas but they’re very different. Callas are popular cut flowers. The tuber-like rhizomes should be planted in the spring and also need to be dug up after a frost kills the foliage. Store them in peat moss or vermiculite in an open box or paper bag for the winter.
Gladiolus are the tall, multi-bloom spiky flowers popular in floral arrangements. Gladioli come in almost any color. They are easily grown from corms, which is similar to a bulb. Plant them in the spring after temperatures and the soil warm. They must be dug up in the fall and stored similar to Callas. Some Iowa gardeners treat gladiolus as an annual and just plant new corms each spring.
Dahlias are my favorite flower. They are native to central Mexico and come in truly one of the widest varieties of colors, sizes and forms. These beauties range from around 6 inches to 6 feet in height. The flowers can be as large as 12 inches in diameter in the “Dinner Plate” varieties. The tall Dahlia’s require staking, full sun and fertilizer. They can be planted directly in the garden after frost has passed or started indoors in pots. Dig up in the fall and overwinter in a cardboard box in a layer of dry vermiculite, peat moss or wood shavings.
Tuberous begonias are the showy ones that come in bright colors and like shady areas. They’re popular for containers and hanging baskets. Tuberous begonias bloom throughout the summer, but unlike the houseplant begonias require a dormant period. Dig the begonia tubers after a killing frost, cut the stem to about 2 inches and let dry indoors. Once dry store in peat moss or vermiculite in a covered box or bag in a cool dry location.
Adding a variety of bulbs to your garden can be very rewarding, but over-wintering tender bulbs does require a bit more maintenance.