This is an updated version of a Plug article sent out in Spring 2019 from North Creek Nurseries.
There are three main growing periods of weed life cycles in the Mid-Atlantic: early spring as soil temperatures increase, early summer when winter weeds die out and summer weeds begin active growth, and late summer/early fall, when summer weeds are setting seed and winter annual weeds are germinating. Controlling weeds at the right time is an important tool to effectively manage weed pressure in the landscape.
In fall, as the days get cooler and the soil temperatures hovers around 65F, winter weeds sprout, hoping to get a head start for the next spring. Though no larger than a few leafs, these weed seedlings will bide their time over the winter, waiting. When soil temperatures warm in early spring, winter annual weeds attempt to outcompete other plants nearby by quickly growing, either by producing as much vegetative mass as possible to smother competition or by flowering and setting seed. There is a critical time period between weed emergence and weed removal where removal must occur or else weeds reach critical mass and will overtake the space. This is called the critical weed-free period in crop science. While this theory is applied mostly to agricultural crops, the same idea can be applied to the landscape. A couple of hours of weeding done at the right time can prevent a larger time investment to weeding later down the road.
It is important to identify and know the life cycles of common weeds in the landscape to ensure the correct weed management timing and protocol. The top worst winter annual weeds one finds in the Mid-Atlantic garden are common chickweed (Stellaria media), henbit (Lamium amplexicaule), horseweed (Conyza canadensis), purple deadnettle (Lamium purpureum), and shepherd's purse (Capsella bursa-pastoris). Click on the links to learn more about these common winter annual weeds and the different ways you can manage them (from biological methods to mechanical to cultural to chemical). Learn more about garlic mustard, a perennial weed easily spotted in the winter.
Knowing when these plants emerge and attacking them at their critical point will save you hours of labor. While weeds will keep on emerging, despite our best efforts, the number of plants germinating and the speed in which the plants mature is the reason gardeners should plan garden maintenance and weeding schedules at critical weed-free periods.
Flame weeder. Click HERE for details about the make and model.
The standard weeding tools can be used here - your hands, a hoe, or if the landscape has a fair amount of room, a flame weeder. Flame weeders are most effective on newly-emergent weed seedlings. The roots are not well-established and the leaves are immature allowing the fire to penetrate the cell walls and kill the plant entirely. One can easily walk through the garden and eradicate hundreds of seedlings without disturbing the soil and the seed bank or destroying well-rooted perennials nearby.
Interested in learning more about weeds in the landscapes and the best methods to control them? Check out this guide from Penn State Extension.
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