Frost Protection for Tender Plants
It’s that time of year to get those frost blankets ready. The average first frost date in Phoenix is December 16th and you may have several common plants in your yard that need protection from winter freeze and frost. If you take measures to prevent damage to these tender plants, you’ll spare your yard from some unsightly frost damage, yourself from extra pruning come spring and possible plant loss.
Below is a partial list of common frost-sensitive plants. If you have any of these plants or any other sub-tropical plants, you’ll want to take the below listed measures to protect them from frost and freeze damage.
The following are all frost sensitive:
Citrus (young citrus are particularly susceptible)
Thevetia (Lucky Nut Tree)
All varieties of Carissa (Natal Plum)
Tecomaria (Cape Honeysuckle)
Tecoma (Yellow & Orange Bells)
Passiflora (Passion Flower)
Senecio (Mexican Flame Vine-Let go deciduous, or won’t bloom next year)
Solanum (Potato Bush/Vine)
Cuphea (Mexican Heather)
Nerium (Oleander-saves the bloom)
Petunia (Saves the bloom)
Geranium (Saves the bloom)
Lobelia (Saves the bloom.)
For home use, we recommend using geotextile fabric, otherwise known as a frost blanket to cover tender plants. A frost blanket gives 7 to 10 degrees of frost protection. We recommend against using burlap, bed sheets or plastic. Burlap is heavy and messy (fibers) and the fibers are open and loose; bed sheets are quite thin and only give a couple degrees of protection; and plastic doesn’t breathe and can actually compound damage to the plant.
A frost blanket can be left on during the day since it allows light and water in and doesn’t allow the warmth from daytime heat to escape. Additionally, the frost blanket is economical and can be folded and stored to be used for many years to come. If you get caught without a frost blanket and need to use what you have on hand, be sure to uncover your plants during the day so photosynthesis can occur.
To properly cover a plant, drape the blanket over the top of the plant and allow the blanket to flow to the ground weighting the bottom if needed.
Columnar cactus tips on the other hand can be covered with Styrofoam cups.
For large areas or plants/trees that are too difficult to cover, you can also use an anti-transpirant like Anti-Stress 2000. This particular product is a non-toxic liquid that’s mixed with water and sprayed on leaves for approximately 5 degrees of protection. Once applied it is active from 45 to 60 days. Anti-Stress 2000 can be used on edible plants, but no later than 45 to 60 days before harvest and we generally recommend against using it on edible plants. You get best protection when Anti-Stress is applied 24-48 hours before frost is predicted. This product is particularly helpful when hard freezes are predicted used in conjunction with frost blanket on landscape plants or sprayed to protect fruit blossoms from frost.
Frost damage is evident when leaves become discolored after a frost–usually they turn black. If plants are damaged by frost, DON’T prune them! The damaged branches will actually add protection from additional frost damage for the duration of winter. If you cut that off, future damage can occur to the newly exposed branches. Wait until all frost is over to cut the damaged areas back. In the Valley, that is around the beginning to the middle of February.
Kari Petterson is the sales & marketing coordinator for Terra Verde Landscape Solutions.
She can be reached at 480-497-8200 or firstname.lastname@example.org