Late spring frosts
Spring frost that occurs after the first week in June often threatens many of the tender plants we may have placed outdoors in our gardens already. Simple methods of protection include covering the plants with cloth fabric, plastic sheeting, or straw. Be sure to remove the protection once temperatures warm again. If you have an area too large to cover physically, but with a sprinkler available, run the sprinkler continuously throughout the freezing temperatures until the ice melts off the plants naturally. This method, however, is somewhat tricky. The mistake most people make is to turn the sprinkler off once temperatures are above freezing while there is still ice on the plants they are protecting.
Remember, low areas are more susceptible to freezing and may have a shorter growing season by as much as two weeks on the same property. For large trees and shrubs there is little you can do. Many of our native plants are quite tolerant of near freezing and just freezing temperatures. When a hard frost of 28 degrees or so threatens, you may lose some flower buds on early flowering shrubs and trees. This is often the reason that we have poor fruit set on apricots in Minnesota.
Make sure the plants you have selected for your landscape are hardy for your growing zone, which is zone four for the southern part of the state and zone three for areas north of the Twin Cities. For lists of appropriate plants contact your University of Minnesota Extension County Office.