The Winter Storm did a number on outdoor plants. But all hope is not lost in saving them before spring. ACC’s Sustainable Agriculture Department shares expert tips to keep your garden growing.
By: Savannah Rugg, Agriculture Department Chair
Recommendations for Freeze-Damaged Plants
Succulents/Cacti: If you see evidence of bacterial rot symptoms (usually indicated by watery, soft, black spots on the plant), prune the affected areas back to healthy tissue, removing approximately half an inch of healthy material from around the affected area. You will want to sterilize any tools with a 1-part bleach to 10-parts water solution to prevent the infection from spreading further. Do not do any further pruning until all danger of a freeze/frost has passed for the season.
Small Shrubs/Vines: If your plant has been killed all the way to the ground, prune your plant with clean, sharp cuts leaving approximately 6 inches of growth out of the soil. You may leave them covered with mulch for the time being, but rake the mulch back after the possibility of freezing weather has passed so that the sun and light can aid in recovery. Be patient – it can take up to four months for plants to come back from freeze damage.
Large Shrubs/Trees: Even if you do see damage to your large plant, it is best to leave it alone until all danger of freezing weather has passed; the dead plant material can actually help the healthy parts of the plant survive the rest of the season. Once the weather has warmed up a bit, take a look at any new growth to assess the extent of damage on any particular part of the plant. Carefully prune away the dead portions, cutting about half an inch above any new buds. This would be a good time to be intentional with your pruning in regard to the desired direction of plant growth.
Be Prepared Next Time!
Here are tips on what to do the next time a freeze is forecast for our area:
Give your plants (except cacti and succulents) a good watering a day or so before the forecast freeze date; drought-stressed plants are less able to weather the elements, plus the moist soil provides a good “heat sink” for the plant via increased heat absorption through the day and slow radiation through the night. Be sure not to overwater though.
Move container plants to a sheltered area – they are the most susceptible to freeze damage because they have less soil to protect the root system; the additional soil around in-ground plantings also provides a “heat sink” that helps during freezing temperatures.
Cover your plants with a lightweight plant cover fabric (available from garden centers or via the internet) – this will help keep the heat radiating out from the soil close to the plant. You can also use a regular household blanket, but be sure to support it with a frame of some kind so that you don’t damage the more tender parts of the plant. Make sure that the cover extends to the ground around your plant and doesn’t end at the base of your plant. Additional protection can be provided with a layer of plastic over the fabric or blanket, but make sure that the plastic does not touch any part of the plant directly as it can burn the leaves of the plant. It is best to remove the cover during the day to allow the sun to heat up the soil and then re-cover the plants at night.
Provide additional sources of heat underneath the covers in the form of a string of outdoor Christmas lights (making sure that the lights are incandescent, as LED lights don’t emit heat). The lights should not be touching any plant tissue to avoid heat damage. Another way to provide some supplemental heat underneath the covers would be through the use of milk jugs filled with water, which (like the moist soil mentioned above) will store heat during the day and radiate it out at night. As with the lights, make sure that the jugs are not directly touching any part of the plant to prevent damage from condensation.
For perennial plants a layer of mulch can be beneficial – old leaves are the best but you can use regular mulch as well (just don’t bury your plants, which could prevent water from getting to the soil).
ACC’s Sustainable Agriculture program allows students to learn about sustainable agriculture, soil and water conservation, soil science, product marketing, horticulture, animal science, and small farming. The college offers two unique degree plans: the Associate of Applied Science in Sustainable Agriculture and the Associate of Science in Sustainable Agriculture. There also are short-term certificates and awards available through ACC’s Continuing Education Division. Students enrolled in the programs have access to the college’s 17-acre sustainable farm located at ACC Elgin Campus.
For more information, and to register for courses, visit austincc.edu/agriculturesciences.