What does a severe freeze mean for your landscape?

Plants that are most susceptible to freeze damage are those on the fringe of hardiness; for example, a plant that is rated for USDA Zone 7 would be considered on the fringe in central Oklahoma.  Plants in pots (as opposed to those planted in ground), plants with existing damage from drought, drainage issues, insects or diseases, and newly planted material are more at risk from a freeze as well. 

Plants that are fully winter hardy in our zone should be fine during a typical hard freeze.  You may notice signs of winter damage, especially on new growth and blooms that have already opened, but winter hardy plants should recover. 

Follow the tips below to protect plants on the fringe for your hardiness zone as well as plants in pots, plants trying to recover from previous damage, and anything newly planted:

• When possible, move indoors tender, just barely hardy, and plants in pots as they are the most susceptible to damage. If this is not possible due to the size or weight of the plant…..
• Use frost blankets.  Frost blankets work by trapping heat from the soil and raising the temperature inside the covered area above the actual outside air temperature. The covering should be secure all the way to the ground to trap as much ground heat as possible.  Frost blankets should be used for cool season veggies as well as to protect the buds of early spring bloomers like forsythia or flowering quince, for example.  
• NOTE: We do not recommend plastic sheeting, since it can trap a lot of moisture and heat on a sunny day and may cause more harm than good to the plant that you are trying to protect.
• Water plants ahead of a severe freeze; it is best to water 48 hours in advance, when possible.  Pay extra attention to any plants under cover (usually from a roof or awning) that don’t get normal rainfall (especially porch pots). Water is a great insulator for plant roots, and wet soil is warmer that dry soil.
• Add mulch around landscape plants to protect roots from freezing temperatures.  Mulch also helps to maintain soil moisture.
• Use Wilt Pruf to further protect plants from drying out, drought, wind burn, and winter kill.
• Don’t forget to disconnect water hoses, protect water spigots, and drain your hoses to protect them from damage as well.  

*PLEASE NOTE:  These are basic tips for normal hard freezes within the average lows in our USDA Plant Hardiness Zone.  In central Oklahoma, the USDA Hardiness Zone is 7a (0°F to 5°F).  If you aren’t sure of the USDA hardiness zone in your area, you can check here: USDA Plant Hardiness Zone Map.