Question:
What are the general rules about mulching plants for cold weather protection? I see very little being done, but I’m new to the area.Answer:
- Mulching plants with straw and other materials are used to insulate their roots when the ground freezes. Fortunately, the ground never freezes in the Bay Area, so mulching isn’t necessary.
- But we do get freezing temperatures that damage and even kill many plants. Summer color and other soft tissue, herbaceous plants are the first to go. The key to the damage with woody ornamental plants is how long the temperatures stay below thirty-two degrees after the sun rises and how much moisture there is in the ground.
- Cold is a descant. It withdraws moisture from plant cells at a very rapid rate. This results in the burnt or brown foliage and in severe cases, the plant(s) don’t recover. Hence it’s essential to water container plants before a frost. Frost damage is a concern when the air is still and never an issue during windy conditions.
- The wind chill factor is of no concern with plants, as they have no central nervous system. Only the actual temperature affects them. Herbaceous herbs such as parsley, basil, and others don’t survive most cold periods and are replanted each spring. Sage, Oregano, Rosemary and other woody varieties are not effective by our winter temperatures
- We protect cold-sensitive plants like Citrus, Bougainvilleas, Mandeville’s, Hibiscus and others with Bonide Wilt Stop or Cloud Cover. These products put a protective film or barrier on the leaves. I like to refer to them as ‘ChapStick’ for plants.
- Also, plants can be covered with N-Sulate or similar plant blanket. N-Sulate is a UV treated, reusable tarp-like covering available at many garden centers. It is used to drape groups or clusters of plants.
- You could also use sheets or blankets, but plastic sheeting is not recommended. With plastic, the cold travels right through the material. This is not the case with the other materials.
- Plastic could be used as long as you ‘tent’ the plants keeping the material from contacting the leaves. It is not recommended to wrap plants long term as we do with water pipes for the winter.
- Typically, we would expect out coldest temperatures in January and February. It is not recommended to prune off any of the cold-related damaged until March.
Question:
This summer I wrapped the trunks of my young Redwood trees with burlap. The burlap protected the trunks from the deer rubbing against them. Should I continue to leave the burlap on during the winter?Answer:
- I wouldn't keep the burlap on year round. If the deer continues to be a problem next year, then I'd look to encircle the tree(s) with a wire cage. Most home improvement retailers have a heavy-duty wire along with rebar to make it strong enough to resist the deer.