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Got gardening questions? Contact the Hortline at (515) 294-3108 (Monday-Friday, 10 a.m. - 12 noon and 1-4:30 p.m.) or send an e-mail to hortline@iastate.edu. For more gardening information visit us at Yard and Garden Online at www.yardandgarden.extension.iastate.edu

2/22/2006

Can I plant gooseneck loosestrife in my garden? 

Common plant names are sometimes confusing.  Two groups (genera) of plants share the common name of loosestrife. 

Numerous states, including Iowa, Minnesota, Wisconsin and Illinois, ban the planting of purple loosestrife (Lythrum spp.).  Purple loosestrife is an attractive herbaceous perennial.  Plants produce pinkish purple flowers on dense, 1-foot-long flower spikes in mid to late summer. Unfortunately, purple loosestrife is also an invasive weed. It adapts readily to natural and disturbed wetlands, forming dense stands that outcompete and replace native grasses, sedges and other wetland plants. 

The scientific name of gooseneck loosestrife is Lysimachia clethroides. Gooseneck loosestrife produces small, white flowers on 6- to 12-inch-long, curved flower stalks. The curved flower stalks resemble a goose’s neck, hence the common name.  Gooseneck loosestrife can be planted in the home garden in Iowa. While it is not a noxious weed, gooseneck loosestrife does spread rapidly. Plants should be dug, divided and replanted every two to three years to keep it from crowding out nearby perennials. 

When pruning trees, is it desirable to make flush cuts? 

Do not make flush cuts when pruning trees. Flush cuts are pruning cuts made as close as possible to the trunk or main branch. They destroy the tree’s natural defense mechanisms that promote wound compartmentalization and callus formation.  When pruning trees, make the final cut just beyond the branch collar and branch bark ridge. The branch collar is the swollen area at the base of the branch. The branch bark ridge is the dark, rough bark ridge that separates the branch from the main branch or trunk. Pruning just beyond the branch collar and branch bark ridge retains the tree’s natural defense mechanisms and promotes compartmentalization and callus formation. 

Is it possible to move an established asparagus bed? 

The root system of an established asparagus plant is quite large. As a result, transplanting attempts are usually unsuccessful. Large, established plants will be severely injured during the transplanting process. Some plants may actually die.  Those that survive may never produce a good crop. If you would like to establish a new asparagus bed, it’s advisable to purchase crowns from a garden center or mail-order nursery and plant in early spring. Asparagus performs best in fertile, well-drained soils in full sun. 

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Contacts :

Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu

Jean McGuire, Continuing Education and Communication Services, (515) 294-7033, jmcguire@iastate.edu

No photos are available for this week's column.