Contributed by Jennifer Tufts, Master Gardener
July conjures up images of hot, lazy days in the sun, juicy watermelons, ice cream, fireworks, and summer flowers. Most of the serious planting work is done. Now it's time to sit back and enjoy the long days, harvest the fruits of our labors, watch the fireflies, and, of course, pull the weeds.
Thoughts of Fourth of July celebrations inspired this Master Gardener to look into our country's ecological history. On Independence Day, Americans remember a victory that seems long behind us. But, in fact, we are standing side by side with Paul Revere and the Minutemen of the Revolutionary War every time we weed the garden. You may not need to be on the watch for Red Coats coming over the hill with loaded muskets, but remnants of that invasion still linger in our countryside.
In 1778, General George Washington, based in Brunswick, N. J., directed his army to put "green boughs" in their hats, issued them a double allowance of rum, and ordered a Fourth of July artillery salute to commemorate Independence Day.
What he probably could not imagine was that long after the English troops surrendered at Yorktown in 1781, their ecological allies would continue to occupy and dominate North America. You might very well see many of the same green boughs George Washington was familiar with out your back door or on a walk in the Erving or Quabbin state forests. You will also find plants that arrived with the wave of European colonists - and some that have traveled from distant parts only recently.
In his book, “Ecological Imperialism: The
Biological Expansion of Europe, 900-1900”, Alfred W. Crosby makes the
case that European migration took many forms: human, microbial, and
biological. With European domination came the advances of agriculture,
including concentrations of plants and animals that brought with them
populations of predators, including insects (mosquitoes!), fungi,
bacteria and viruses. Crosby notes that there were "three kinds of life
forms that often passed over the seams of Pangaea and usually prospered
in the colonies, not with, but often without help and even despite
European actions: weeds, feral animals, and pathogens associated with
humanity." "Sixty percent of the more important farmland weeds in Canada
are European. Of the 500 equivalents in the United States, 258 are from
the Old World, 177 specifically from Europe." What more proof do you
William Cronon writes that "Grazing animals were among the chief agents in transmitting to America one of the central - albeit not applauded - characters of European agriculture: the weed." Ragweed was already here and we can only hope it gave the British soldiers a bad case of hay fever ... but 22 European weeds came on the scene as early as the mid-1600s: dandelions, chickweed, Shepherd's purse, bloodworts, mulleins, mallows, nightshades and stinging nettles, to name a few. "With fences had come the weeds: dandelion and rat alike joined alien grasses as they made their way across the landscape."
So, a weed is a weed is a weed, right? Not so fast. There are weeds and then there are dangerous weeds! All weeds are characterized by their ability to produce large numbers of seed as well as their adaptability, meaning that they can withstand high or low temperatures and long periods of drought. They also reproduce with a vengeance, both by seed and by asexual means. All gardeners know the back-breaking work of hand pulling and hoeing as a means of controlling weeds, and that can certainly be effective, especially against annuals, but you may need other weapons in the battle against biennial and perennial weed invasions.
If it is a lawn you are trying to save, you might consider Carbohydrate Starvation to keep the crabgrass, spotted spurge or goosegrass under control. Every growing plant needs leaves to store carbohydrates and flourish, and if you mow often enough you will seriously limit the spread of the weeds. It's not pretty, I know, but remember, this is war. Mow and mow again, removing the seed head of your worst lawn enemies, and starve them out!
Ratcheting up the intensity a bit, there is the smothering tactic for certain unwanted intruders. Obviously, this method will not work on your lawn, but for a targeted area in the garden, between the rows of tomato and squash plants, you can stop weeds cold with ground covers, including carpet, tarps, weed fabric, paper, plywood or plastic.
Another tool in the guerrilla warfare arsenal, albeit the last resort of the weed warrior, is flaming. Beware of torching your neighbor's fences, areas of vinyl siding, mulch or dry grass in the vicinity. Basic safety regulations apply, such as keeping a safe distance from the plants you want to save and any exposed body parts. But don't hesitate to do what you have to do, patriots! This is not just about ugly - this is about the integrity of our countryside!
Because this is the third century of the struggle, after all, we do have some highly modern weed control substances to recommend. There are brand new herbicides containing vinegar (yes, vinegar!) to control Canada Thistle seedlings. Other modern organic products useful for spot treatment of weeds are made from yucca extracts, acetic acid and/or lemon juice. Corn gluten meal contains a compound to inhibit germination and can take out 50%-60% of the vegetative varmints in the first year, 80%-90% by year three. Don't hold back. Throw the whole kitchen cabinet on the problem if that's what it takes!
If you want to do something a little less violent than throwing vinegar on the ground to win the war of European aggression, let me suggest that you visit Nasami Farm or the internet to learn more about our region's native plants. A native plant is generally understood to be any plant that existed here in Western Massachusetts prior to the arrival of Europeans. Whereas only 3%-4% of non-native species of plants are likely to become a nuisance by displacing native plants or endangering wildlife with a loss of shelter or food, there are several unwelcome invasives around, and we need to watch that we don't contribute to the problem by encouraging them. Unfortunately, some well-known and all too common plants, such as Norway maple (Acer platanoides), multiflora rose (Rosa multiflora), oriental bittersweet (Celastrus orbiculatus), and burning bush (Euonymus alatus) are in this category.