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Freeze Warning

The National Weather Service has issued a Freeze warning from Midnight until 10:00 AM Wednesday.

Forecast lows tonight include 27 in Washington, 28 in Petersburg and 26 in Linton.Sensitive vegetation could be killed.

The following was prepared by Rosie Lerner, Purdue Consumer Horticulture Specialist.
Spring Frost Can Spoil the Show
Rosie Lerner, Purdue Consumer Horticulture Specialist
Released April 4, 2007
At long last, signs of spring are everywhere. Forsythia, daffodils and magnolias in bloom; trees pushing out their buds; and songbirds chirping happily. But along with the hope of spring, winter's last gasps in the form of frost and freeze can spoil the show.

The further along the plant buds are in their development, the more likely they are to be damaged by below-freezing temperatures. The lower the temperature drops below freezing, the more damage can be expected. Also, different species of plants vary in their susceptibility to freezing. High winds accompanying these low temperatures, cause tender plant tissue to dry wilt because the plant is losing water faster than it can replace it.

Early spring flowering trees and shrubs are most likely to have some flower damage, since many are alerady in flower are at least breaking bud. Depending on the conditions mentioned above, the damage may just be brown edges along the petals, or it may be failure to bloom. For fruit crops, every flower that is freeze-damaged results in decreased fruit potential.

Foliage buds generally are considered to be more resistant to cold damage. Depending on the severity of low temperatures, freeze-damaged foliage buds usually leaf out as warm weather returns. However, foliage will likely appear distorted, scorched and/or tattered. Most plants should be able to outgrow this type of damage.

Spring-flowering bulbs, such as daffodil and tulips, are also likely to be damaged if temperatures drop into the teens and low 20s. The flowers can take freezing temperatures without much damage, but colder temperatures likely will cause some damage to flowers and foliage. If flowers are in full bloom when frost or freeze strikes, the flowers may wilt as the flower stalk thaws.

Many gardeners ask if they should cover the plants for protection. Blankets, tarps, etc., may be able to provide a few degrees of warmth, but if temperatures drop down into the teens, the covers may not be sufficient to prevent damage. Snow is a great insulation, but if it is heavy and wet, the weight may cause stem breakage on tender shoots. Likewise, blankets can become heavy from snow load and cause breakage. Providing some support under the blanket in tent-like fashion should help prevent mechanical damage. Keep in mind that even if the flowers are damaged, the bulb is well-protected down in the soil. If the foliage is allowed to mature, the bulbs should make a good comeback next year.