Extension News

Ask the ISU Extension Garden Experts: Evergreens, Tulips, Barberries and Tomatoes

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

7/1/2009

I would like to plant a low-growing evergreen on a slope. What are possibilities?

There are a number of low-growing juniper varieties, such as ‘Blue Rug,’ ‘Blue Chip’ and ‘Prince of Wales.’ Junipers require at least six hours of direct sun each day. Russian cypress (Microbiota decussata) can be successfully grown in partial shade (two to four hours of sun). Russian cypress has medium green foliage that is similar to that of arborvitae. It grows about one foot tall.

When can I move tulip bulbs?

Tulips can be dug up and replanted as soon as the foliage dies back (turns brown). Tulips also can be dug up and replanted in fall (October). If you would like to move the tulips in fall, mark the site when the foliage is present so the bulbs can be located in October. Tulips perform best when planted in a well-drained soil in full sun.

Several barberry stems have suddenly wilted and died. What could be wrong?

The wilting of individual barberry shoots may be due to Verticillium wilt. The Verticillium wilt fungus blocks water-conducting tissue within the stem, causing the stem to wilt and die. The only thing that can be done is to prune out the dead shoots (when they appear) and destroy them. Verticillium wilt cannot be controlled with fungicides. Verticillium wilt may continue to destroy the plant stem by stem or it may suddenly stop and the remainder of the plant may survive.

Several leaves on my tomato plant have curled up. Why?

The curling of the tomato leaves may be a physiological disorder referred to as leaf roll. Affected leaves roll upward and inward. The leaves also may become thickened, giving the foliage a leathery appearance.

Leaf roll often occurs after a heavy rain, plants have been severely pruned or the plant’s roots have been damaged by deep cultivation. Leaf roll does not reduce crop yield or quality. Leaf roll is usually a temporary problem. Plants typically recover on their own.

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Contacts :

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

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