Extension News

Ask the ISU Experts

Note to media editors:

Got gardening questions? Contact the Hortline at (515) 294-3108 (M-F; 10-12 & 1-4:30) 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


What is the proper way to plant strawberries? 

When selecting a planting site for strawberries, choose an area that receives full sun and has a well-drained soil. Do not plant in weed infested areas. Perennial weeds, such as quackgrass, are extremely difficult to control in strawberry plantings. Also, avoid sites where strawberries, tomatoes, potatoes and peppers have been grown in the last two years to reduce the possibility of root diseases. 


Purchase virus-free plants from a reliable garden center or mail-order nursery. Plants from an old planting or the neighbor’s garden are often diseased. If planting must be delayed after purchase, place moist wood shavings or peat moss around the roots of the plants and place them in a plastic bag. Store the plants in the refrigerator at 32 to 40 degrees F. They can be safely stored in the refrigerator for one to two weeks. 


April to early May is the best time to plant strawberries in Iowa. Remove the strawberry plants from storage when ready to plant. Trim off the older leaves, place the roots of the plants in water for one hour, then plant immediately. Set each plant in the ground so the crown of the plant is even with the soil surface. 


The type of strawberry determines plant spacing. June-bearing strawberries should be planted 18 to 24 inches apart within the row. Rows should be spaced 4 feet apart.  Everbearing and day-neutral strawberries are typically planted in beds consisting of two or three rows.  Rows should be spaced 1 foot apart within the bed. In the row, space plants 1 foot apart.  Beds should be separated by 2-foot-wide paths. 


How do I prune my hybrid tea roses in spring? 

The upper portions of hybrid tea, grandiflora, and floribunda roses typically die due to exposure to low winter temperatures and extreme temperature changes. When the winter protection is removed from these roses in early spring (late March to mid-April), gardeners should prune out the dead wood. 


Identifying live and dead wood is easy. Live wood is green and has plump, healthy buds. When pruned, the center of the stem (pith) is white. Dead wood is brown, has no live buds and the pith is brown or gray. 


When pruning roses, make the cuts at least 1 inch below the dead, brown-colored areas on the canes. Make slanting cuts about one-fourth inch above healthy, outward-facing buds. The slant should be made in the same direction as the bud. Remove the entire cane if there is no sign of life. 


Because of our severe winter weather, hybrid tea, grandiflora and floribunda roses often suffer a great deal of winter damage. Normally, the primary objective of rosarians in the upper Midwest is to remove all dead wood and save as much of the live tissue as possible. If the roses suffer little winter damage because of a mild winter, prune the rose canes back to within 8 to 12 inches of the ground. 


Should I apply lime to my garden? 

In Iowa, gardeners should apply lime to gardens and lawns only when recommended by a soil test. A soil test will indicate the current soil pH and, if necessary, the amount of lime to add to the area. Liming materials include ground limestone which is mainly calcium carbonate (CaCO3) and dolomitic limestone which contains calcium carbonate and magnesium carbonate (MgCO3). 


Lime is applied to acidic soils to raise the soil pH. The soil pH is important because it influences the availability of essential nutrients. The pH scale runs from 0 to 14. Any pH below 7.0 is acidic and any pH above 7.0 is alkaline. A pH of 7.0 indicates a neutral soil. The optimum pH range for most flowers, vegetables, and other horticultural crops is between 6.0 and 7.0. Lime is applied to acidic soils with a pH below 6.0 to raise the pH into the optimum range. However, an application of lime to an alkaline soil can raise the soil pH to excessively high levels, reducing the availability of plant nutrients and leading to poor plant growth. 




Contacts :

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

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

There are no photos for this week's column.