Biennial weeds form roots and a rosette of leaves the first year and set seed the second. Perennial weeds live for more than two years and are the most difficult to control since they can reproduce four different ways: By seed, roots, stems and/or by stolons.
Weeds may be annuals, biennials or perennials. Annual weeds are the easiest to control. They complete their life cycles in a year or less. Summer annuals, like lamb’s quarters, sprout in the spring and go to seed in the fall. Winter annuals like chickweed sprout in the fall, over-winter and then go to seed by late spring or summer.
Getting to the root of the matter
Gardening between the lines
Use vertical barriers like wood, metal, stones or heavy-duty plastic edging between lawn and garden areas to prevent grass from sneaking in. Once certain grasses get a stronghold in your garden, it’s difficult to get it out.
Gardeners can create a stale seedbed by very lightly and shallowly working the very surface of the soil repeatedly, causing seed to germinate until the seed bank in that layer is exhausted. Others will use a quality mulch/compost to keep those seeds in the dark to prevent germination. If there is time and space to do soil solarization in your growing rotation, then that becomes a real option.
Given the opportunity, a gardener can reduce that seed bank, which is sitting there, just waiting for conditions to be right to sprout. More than 90 percent of our weed seed germinate in the spring, so we should focus on seed germination prevention, dealing with the weeds while they are just seedlings and easily removed.
That chickweed mentioned earlier can produce 25,000 seeds that immediately fall to the soil. University of Massachusetts lists our troublesome crabgrass as producing about 150,000 seeds every year. Crabgrass is not limited to growing in the lawn either.
It’s amazing how prolific and hardy some of these weed seeds are. Dr. Mark Renz, working from literature from the California Weed Science Society’s “Principles of Weed Control,” third edition, compiled information of a number of weeds, providing the number of seeds produced by a single plant and how long we can expect them to be viable in the soil. Here are a few common weed plants we find every year in our beds:
Common purslane gives us up to 2 million seeds annually, but the good news is they may only last about 5 years in the soil. Compare that to Eastern Bitter Nightshade only giving up 825,000 seeds, BUT lasting 40 or more years. I pick the purslane!
On the danger of allowing weeds to grow and seed themselves: also used figuratively. □ 1866 Rural American 1 Dec. .
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