Protecting plants from late-spring freezes
AMES — Spring is just around the corner, but that doesn’t necessarily mean the end of freezing temperatures associated with a late-spring frost.
ISU Extension and Outreach horticulturists can help answer questions about late freezes and their effects on flowers and plants. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or firstname.lastname@example.org.
When should I remove the straw mulch on my strawberry bed?
To reduce the chances of crop damage from a late frost or freeze, leave the mulch on as long as possible. Removing the straw in March might encourage the plants to bloom before the danger of frost is past. Temperatures of 32 degrees F or lower might severely damage or destroy open flowers. Since the first flowers produce the largest berries, a late spring frost or freeze can drastically reduce yields.
To determine when to remove the mulch, periodically examine the strawberry plants in spring. Remove the straw from the strawberry planting when approximately 25 percent of the plants are producing new growth. New growth will be white or yellow in color. If possible, the winter mulch on strawberries should remain until mid-April in central Iowa.
When removing the mulch, rake the material to the aisles between rows. If there is a threat of a frost or freeze later in spring during bloom, lightly rake the straw over the strawberry plants.
When should I remove the soil around my hybrid tea roses?
Remove the soil, straw and other protective materials in late March in southern Iowa, mid-April in northern portions of the state. A frost or freeze in early spring won’t harm the roses.
After removing the protective materials, prune out any dead wood. Live wood is green and possesses plump, healthy buds. Dead wood is light to dark brown in color. When pruning, make the cuts about 1 inch below the dead, brown-colored sections. Remove the entire cane if there is no sign of life.
When should I remove the winter mulch on my chrysanthemums?
Leave the straw or pine needles on the chrysanthemums until new growth appears in early spring, typically late March in southern Iowa and mid-April in northern portions of the stateCrown rot might become a problem if the mulch is not promptly removed in early spring.