BEWARE of late spring FROSTS
Spring may be here but this doesn't mean the end of cold weather and the potential for frost!
Some things you may not know about frost:
- Temperatures do not have to drop below freezing for frost to occur.
- Frost can occur even at 38oF or 40oF if the night is clear and the winds are calm!
- If there is cloud cover and the night is windy, frost will not usually settle on the ground or plants even when temperatures drop to 34oF.
- White frost generally occurs when temperatures are above the 32 degree mark and is usually less damaging to plants than a black frost.
- Black frost occurs when temperatures fall below 32oF - down to around 28oF or lower.
- Black frost is always a killing frost because it damages plant tissue causing a blackened appearance to the foliage.
- Certain perennials are more susceptible to frost and freeze damage once they begin growing. These include Hosta, Astilbe, Cimicifuga, Kirengeshoma, and Japanese anemones.
Watch the temperatures and be prepared to cover tender new growth if a frost or freeze is forecast.
- Blankets, sheets, or cardboard boxes can be used to protect plants from frost or freeze damage.
- These covers prevent the frost from settling on the foliage and physically causing damage.
- In addition, covering preserves the ground heat and keeps the temperatures warmer under the cover.
- Keep the plants covered until the temperature rises above 38oF or 40oF or the frost melts off.
- Be careful not to leave the covers over the plants in the sun or they will cook!
If severe frost or freeze damage does occur on the above listed perennials, they can be sheared back and will flush out with fresh new growth.