Picture yourself surveying the garden in June or July making notes of those empty spots. You muse aloud, surely something could be found to fill the void and compliment the neighboring plants.
The perfect solution could be summer flowering bulbs. They can provide a multitude of color, height and texture that can be quite different from your existing plants. For the purpose of this column, a bulb is a catch-all term to refer to plants, which start out as self-sufficient underground storage organs. The term includes true bulbs, corms, rhizomes and tubers, some of which produce the most exotic plants a gardener could grow.
True bulbs have a short basal stem covered with fleshy leaf scales which surround the embryonic flower shoot. All of this is covered with a dry tough coat for protection. Corms consist mainly of stem tissue attached to a basal plate and covered with thin, scaly fibrous modified leaves. In both true bulbs and corms, the roots develop from the basal plate.
Whereas bulbs and corms have a symmetrical shape, tubers and rhizomes are quite oddly shaped. They consist of modified stem tissue. Tubers have enlarged underground stem tissue with clusters of nonfunctioning leaf nodes. Buds between the nodes are responsible for producing the plant and its roots. Tuberous roots are a modified root system enlarged to store food, which is attached to a stem. Each growing season depletes the food supply, so new roots form next to the spent ones. Rhizomes are creeping stems which send new buds out horizontally that will develop their own root systems and flower stalks, thus increasing the number of plants.
The vast majority of summer flowering bulbs are members of the amaryllis and lily families and are natives of South Africa, Asia and South America. In the United States, most are hardy in USDA hardiness zones 7 through 10. Our USDA hardiness zone in Washington County is either 5 or 6, depending on how close your backyard is to the Laurel Mountains. For the Western Pennsylvania gardener, it means you’ll treat summer flowering bulbs either as annuals and replant them every year or as tender perennials which requires lifting and storing them for the winter.
Winter storage methods will vary somewhat. A good gardening book on bulbs will provide the information you need for each particular plant. Generally, the plants are allowed to die back naturally, lifted from the ground and dried in a dry, shady well-ventilated area. Storage medium for the winter may be peat moss, vermiculite, or a simple dry paper bag. The bulbs are kept in a cool dry spot in your home until planting time in the spring. You will want to wait until after the last frost, which is usually some time during the last two weeks of May here in Washington County.
The following are the names of a few bulbs to plant this spring for a glorious summer display. Allium, or ornamental onions, are bulbous plants with varieties that bloom from late spring through mid-summer. Agapanthus, also known as African lily, is best used as a container plant in our northern climate. Both tuberous begonias and cannas are commonly found in most local garden centers and while we tend to treat them as annuals, they can be lifted each fall and stored until replanting the following spring. Dahlias, Dutch Iris, gladiolas and oxalis – commonly called shamrock plant – can also add a dash of texture and color to your favorite garden bed.
The possibilities are nearly endless for adding summer flowering bulbs to your landscape. I have provided a very short list of some of the summer flowering bulbs that could provide just the right color, height and texture for those empty spots in your garden. Take yourself to your local library to research which ones may be best suited to your personal garden space and enjoy their beauty for years to come.
Trunzo is a Penn State Extension master gardener of Washington County.