Flowering bulbs can really liven up a landscape. They come in an enormous assortment of sizes and colors that some folks say is unequalled by any other flower group. If you are like me, when you think of flowering bulbs it’s the hardy types that come to mind. Spring just wouldn’t be announced without the daffodils, crocuses and tulips. But as much as I appreciate the hardy bulbs, I have grown increasingly fond of the tender ones.
Tender bulbs, or tender perennials as they are sometimes called, cannot overwinter in the western Wisconsin garden. They need to be dug up in the fall, stored indoors through the winter and replanted in the spring. Tender bulbs, however, are well worth the effort. Most offer blooms through the summer and provide a visual feast of shapes and tones. A few popular selections include gladiolus, dahlia, tuberous begonia, caladium and calla lily.
Plant tender bulbs after the danger of frost has passed. When shopping for bulbs you may notice that the term “bulb” is commonly used to refer to plants with storage organs that include corms, tuberous roots, rhizomes and true bulbs. Purchase bulbs that are firm and free of bruises or blemishes.
The gladiolus has long been a favorite of mine. It grows from a bulb-like structure called a corm and blooms from mid- to late summer. To enjoy continuous blooms, plant a few gladioli every two weeks with the final planting in early July.
Another outstanding flower is the dahlia, which grows from tubers. There are reported 42 species of dahlias with over 57,000 different cultivated varieties. They offer a wide range of bloom types and typically flower from mid-summer until frost.
Both gladioli and dahlias prefer sun-drenched locations but for a shadier spot try a tuberous begonia. I have a deep red variety that I keep in a container. This plant adds a beautiful pop of color to my shade garden throughout the summer.
Caladiums are another great choice for partial shade. These tender tubers are prized for their striking foliage, which comes in numerous color combinations of green, white, red, and pink.
Another eye-catching tender perennial is the calla lily. Available in a variety of pastel colors, it brings a tropical, almost exotic feel to the garden. Calla lilies grow from rhizomes and prefer partial shade but will tolerate full sun if kept well-watered.
When the foliage of tender bulbs turns yellow or brown, it’s time to dig them up and prepare them for winter storage. For general guidelines on overwintering corms, tubers, bulbs and rhizomes, check out the UW Madison Extension publication, Storing Tender “Bulb” for Winter.