Extension News

Ask the ISU Extension Gardening Experts

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

10/16/2008

What is a biennial plant?

A biennial is a herbaceous plant that completes its life cycle in two years. The plant produces only leafy growth during the first growing season. Biennial plants flower, produce seeds, and then die in their second growing season. Biennials include foxglove, hollyhock, mullein, carrots, beets, and parsley.

When should I prepare my hybrid tea roses for winter?

Prepare hybrid tea, grandiflora, and floribunda roses for winter after the plants have been hardened by exposure to several nights of temperatures in the low to mid-twenties. Normally, this is early November in northern Iowa, mid-November in central areas, and late November in southern counties.

Are the fruit of the American cranberrybush edible?

The American cranberrybush viburnum (Viburnum trilobum) is a deciduous shrub that grows 8 to 12 feet tall and produces flat-topped clusters of white flowers in spring. After flowering, berry-like fruit develop that turn bright red in fall. The fruit are edible and can be made into jellies and preserves.

What is my plant hardiness zone?

According to the 1990 USDA Hardiness Zone Map, northern Iowa is in Zone 4. The average minimum temperature in Zone 4 is -20 to -30 degrees F. Southern Iowa is in Zone 5. The average minimum temperature in Zone 5 is -10 to -20 degrees F. When selecting trees, shrubs, and perennials, choose plants that are reliably cold hardy in your area.

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Contacts :

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

Del Marks, Extension Communications, (515) 294-9807, delmarks@iastate.edu