How to Protect Plants From Frost Heaving

During cold winter weather the soil contracts and expands as it freezes and thaws. This natural cycle sometimes pops plants right out of the soil. "Frost heaving" can break your plants' roots and leave their root balls exposed to dry, frigid air. Protecting your perennial plants and small shrubs from frost heaving is a simple and easy way to help ensure they live through the winter. Here's what you need to do.

Instructions

1. Insulating the soil from wintertime temperature fluctuations is the most effective way to prevent frost heaving. Apply a 3 to 4 inch layer of mulch around the base of your plants after the ground freezes in fall. Keep the mulch 2 to 3 inches away from the base and crowns of your plants to prevent rotting. Evergreen boughs, pine needles and wood chips are particularly effective mulches because air easily filters between the layers of mulch, providing an extra bit of insulation.

2. Perennials with shallow root systems are most vulnerable to frost heaving (though deeply rooted and established plants can also be affected). According to Iowa State University Extension, many popular perennial flowers, including scabiosa, coral bells, coreopsis and mums are susceptible. Give these perennials time to establish robust root systems that can resist frost heaving by planting them in spring (rather than fall) and keeping them well-watered during the summer.

3. Frost heaving occurs most often in finely textured, loamy soil that has a tendency to stay moist. Digging in 1 to 2 inches of compost each spring and fall will help the soil drain better and minimize the risk of heaving. When adding compost to the soil, make sure that it's not too wet. Digging in wet soil can damage the soil's structure and can create clods. Assess your soil's moisture level by taking a handful of soil and squeezing it in the palm of your fist. If the soil doesn't form a ball, it is dry and fine to work. If it does form a ball, test the moisture level by dropping the ball of soil from waist high. If it easily breaks apart at impact, your soil is dry enough to work. If the ball stays together, or only breaks apart slightly, wait for the soil to dry out a bit more before digging in the compost.

4. Low spots in the garden are most susceptible to frost heaving because water drains into them. In spring or fall, use a bow rake to level out the soil.

5. If your plants do heave out of the soil, press them back into the ground, smooth out the mounds of soil and then apply mulch around the base of the plants.