University of Vermont
Department of Plant and Soil Science

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DORMANT OILS AND OTHER FEBRUARY GARDENING TIPS

Leonard Perry, UVM Horticulturist
and Charlie Nardozzi, Garden Consultant

Applying dormant oil sprays if needed, inventorying seed supplies, and learning about “clean air” houseplants, are some of the garden activities for this month.

Now is a good time to take inventory of your supplies for seed starting. Check quantities of potting soil, containers, labels and similar supplies. Wash any used containers, then disinfect them with a 10 percent bleach solution (one part bleach to ten parts water), or less corrosive solution of a household disinfectant such as Lysol (one part to two parts water).

When a break in the cold brings temperatures above 40 degrees, it's a good time to spray dormant oil on landscape plants infested with scale and other overwintering pests. The oil will smother the insects.  Only apply when the temperature is predicted to stay around 40 degrees, or above, for at least 24 hours.  And, as with any pesticide, make sure to follow label directions.  Some plants, such as maples, may be injured from it and, if overused, it can remove some of the blue color from blue spruces.  Dormant oils are useful to control some scale insects, such as magnolia scale, and mites which overwinter as exposed eggs (not the two-spotted mites).

While many consider genetically modified (GMO) crops as bad, there now is potentially a good plant use—for a houseplant. Researchers at the University of Washington (www.washington.edu/news) introduced a synthetic version of a protein (2E1), which occurs in mammals, into pothos or devil’s ivy.  In humans, this protein is found in the liver and becomes active when we drink alcohol.  So, in this common vining houseplant, it turns on to break down the volatile organic compounds (VOCs) benzene and chloroform.  The former in homes comes from stored power equipment in connected rooms, such as garages.  The latter chemical is present in small amounts in chlorinated water.  This plant could really be helpful, as these chemicals are too small to be captured by HEPA filters.

Although pothos was one of the original “Clean Air” plants, found in the 1980’s by NASA’s Dr. Wolverton of removing some air pollutants, the Washington researchers found that their unmodified pothos plants didn’t remove these chemicals.  They’re now trying to modify pothos further, to remove another indoor pollutant—formaldehyde.  This harmful chemical comes from some wood products, such as cabinets and laminate flooring, and tobacco smoke.  

Other top clean air plants to consider include areca palm, rubber plant, Janet Craig dracaena, Boston fern, and peace lily.  You can find more about these, and others, from the book by Dr. Wolverton (How to Grow Fresh Air: 50 House Plants that Purify Your Home or Office).

When tree and shrub branches bend under the weight of a new snowfall, use a broom to gently brush off the snow. Don't try to remove ice or you might break the branch. It's possible to save a large branch that partially splits from the main trunk if you tie it in place and use long screws (coming from each direction, if necessary) to secure it. If done right away, the tree may callous over the wound and heal itself during warm days.

Other activities for this month include keeping birds fed regularly and heated bird baths cleaned every few days; starting small seeds indoors, such as begonias and pansies; checking houseplants for pests weekly, and fertilizing them if they’re growing; and buying some cut flowers or potted spring bulbs for Valentine’s Day, or just to brighten up your indoors. 

(Charlie Nardozzi is a nationally known horticulturist, author, gardening consultant, and garden coach; gardeningwithcharlie.com).   

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