Potentilla, Bush Cinquefoil Potentilla fruticosa 'Abbotswood.' (Marian Hengemihle, Baltimore…)
A huge swarm of bees is hanging on a tree in our yard. It has been there for over a day, and I hate to spray it because I know we need to protect the honeybees that are left. What do I do?
We have a book full of the names of beekeepers who are eager to come to your house and get your honeybee swarm. Please call us at 1-800-342-2507 and we will refer you. May is a big month for bees to pack up and head out for new territories, though this year we got calls about swarms in April, too.
Suddenly my rosebushes got all red, twisty and clumpy, with thick ugly stems and a million thorns. They had rose rosette disease, and I had to dig them all up. Now I'm told not to replant with any plants in the rose family!
The rose rosette virus does not persist in the soil. You can replant with a rose family plant or even a rose. However, the mites that carried this disease to your roses are still in your area. These minuscule mites can blow in from any infected rose, but they especially spread the infection from non-native invasive rosa multiflora roses that spring up in neglected roadsides and fields. (Their clusters of small white roses bloom in May.) Remove any rosa multiflora in the area, particularly upwind from your site, before you replant roses. If you can't do so, you may want to choose another type of plant for that spot.
University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information. Call 800-342-2507 or send a question to the website at hgic.umd.edu.
Plant of the week
Potentilla, Bush Cinquefoil
At 3 feet high and wide, this deciduous shrub with fine blue-green leaves is a size much sought after by gardeners. It is also known as cinquefoil because each leaf usually has five leaflets. Potentilla's best feature is its flower display, which appears in late spring and continues sporadically through the growing season. Flowers are borne atop the tips of new growth, in white to yellow, pink, orange or red, and are a good source of nectar for butterflies and other pollinators. Peeling woody stems are a rich brown and provide winter interest in the garden. This small, almost zero-maintenance shrub comes in many varieties and makes a lovely addition to butterfly and rock gardens. It is not bothered by deer. Best growth is in full sun, and it tolerates poor, dry soils. Each year before growth begins, prune one-third of the oldest stems to the ground to prevent legginess. — Marian Hengemihle