University of Vermont Extension 
Department of Plant and Soil Science

Summer News Article


Dr. Leonard Perry, Extension Professor
University of Vermont

Three questions many ask us in Extension this month include how to keep rabbits from eating your seedlings, what is the best way to control grubs, and how can you get ahead of weeds in your garden.

If there aren't many rabbits in your landscape, or they aren't very hungry (there are other food sources nearby), then repellents may work.  The usual one is a taste repellent: pepper spray.  Make sure you follow product directions.  Some last longer than others before they need to be reapplied.  And make sure you cover all parts of the plant.  If you spray just the leaves, rabbits may leave them and eat the stems!  I learned this the hard way.

If repellents don't work, you may need to exclude rabbits with a short fence of a material such as poultry wire.  It should be at least 18 inches above ground, with about six inches buried in the ground to prevent digging.  Having dogs or cats in the vicinity may help with control as well.

Margaret Hagen, from the University of New Hampshire Cooperative Extension, suggests applying grub controls from the middle of June to late July are better than spring applications.  In spring, overwintering grubs are very large and feed for only a short period of time.  Later applications will reach young, newly developing larvae that are very susceptible to control.  Consult your local full service garden store and professionals for appropriate chemical controls.

Many gardeners prefer to use alternative grub controls.  Milky spore is a bacterium applied as a dust to turf grass, where Japanese beetle grubs ingest it.  Infected grubs soon die.  Ideal soil temperatures for spore development are 60 to 70 degrees F.  In northern New England, with cooler soil temperatures, control may take several years, if at all.

Beneficial nematodes are also available for grub control.  If they are used, the soil temperature must be close to 70 degrees F.  Nematodes are dependent on moist soils, so it is important to keep your lawn watered for at least a week after application.

Dr. Lois Berg Stack, from the University of Maine Cooperative Extension, says that by learning your weeds, this will indicate how to control them.  Annuals, like crabgrass and lambsquarters, reproduce by seeds.  Pull such weeds, or at least cut off their flowers, before they produce seeds.

Biennial weeds, such as bull thistle and burdock, produce rosettes of leaves near the ground in their first year.  They flower and set seed in their second year.  Dig them out in their first year, or remove their second-year flower stalks before they produce seed.

Many perennials reproduce in more than one way.  Dandelions, for example, propagate quickly from seeds as we all know.  So remove flowers before they set seed.  Or, since they also live for several years from taproots, dig entire root systems to prevent regrowth.

Remember that removing weeds is only the first step.  For long-term control, mulch your garden, develop competitive plantings that will shade out the weeds, and remove weeds diligently and regularly before they get out of control.

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