Each garden has it’s own suite of troublesome weeds – those pesky plants that come back year after year, despite your backbreaking efforts.    Did you know that the plants in your garden actually generate their own unique community of weeds!?  It’s true – a garden of undisturbed shrubs and bushes will tend to promote an understory of shade tolerant, perennial weeds.  Whereas, a garden that is constantly being disturbed and renovated will result in a community of fast growing annual weeds.  The weeds are adapted to the garden condition.

What does this mean for gardeners? First, they can build their garden’s defenses by embracing diversity.  Diversity is critical; in all functional aspects, such as timing of growth, rate of growth, size of plant, life form, rooting system etc.  Each plant in your garden has its own unique form and structure that allows it to capture sunlight, water, nutrients and ultimately – space.   If all the plants in your garden are functionally the same then your garden is only competitive against a handful of weeds.  And, your garden plants will be competing against one another for valuable resources. However, if your garden is functionally diverse then each type of plant will provide competition against a different type of weed.  And, your plants won’t be competing as much with one another.  Take some time to evaluate your community of plant friends – whether they make up a vegetable garden, flowerbeds, or a horse pasture.  Is there enough diversity to create multiple levels of weed competition?

Once defenses are built, gardeners can repel weeds by exploiting the weed’s weaknesses. Fortunately, we have some tools in our arsenal to help our garden plants win the war against weeds.  We don’t have to rely 100% on hand-weeding the garden if we understand the biology of our enemies.  For example, common purslane.  If you have had experience with this weed you know that it can rapidly take over a garden from just a few plants one year, to a dense mat of plants the next.  Common purslane seeds are tiny and germinate very near the soil surface – in the top half-inch.  When you disturb the soil, you bring purslane seeds to the surface – where they can germinate.  Rather than hoeing, a thin layer of mulch will prevent seeds from germinating in the first place.  Or, consider the timing of germination; have you noticed how henbit and chickweed are full grown and flowering seemingly overnight?  These weeds germinate in the fall and overwinter as young seedlings; ready to take off as soon as temperatures are barely above freezing.  Planting a fall covercrop in your vegetable garden will provide excellent competition against these fall germinating weeds and drastically reduce their abundance come the spring.

As always, the better you understand your weeds the easier you’ll be able to win the battle, and the war, in your garden!

Good luck and happy gardening!

Catherine is the Education and Outreach Coordinator for the Thompson Nicola Invasive Plant Management Committee (on Facebook @TNIPMC).   Look for more resources at www.tnipmc.com.