Do Weeds Die In Winter?

What a reward that would be after struggling to keep the weeds in check over the summer months. The truth is that cold weather reduces the activity of weed growth, so weeds do tend to ‘die’ in winter. There’s no time to rest, though. Both summer and winter annual weeds leave their seeds in the soil before they die off, ready for new growth in late summer through the early fall. 

There is no one quick solution for weed removal. There is only management. Understanding the cycle of the weed, and the best time to address them are the best tools in weed management, coupled with patience and timely action. Weed growth is part of nature, and warring with nature is a no-win battle. The best chance for success lies in taking timely precautions and actively understanding the life cycle of the weeds in your garden.

Stepping Stones To Successful Weed Management

The first step to a successful weed management program is proper weed identification. Identification is generally easier once weeds have matured, even though control is most effective when those same weeds are immature and actively growing. It is going to take time to gain the upper hand. Knowledge is power.

The second step is understanding the biology of these undesirable plants. Annual weeds complete their life cycle in a single growing season. Depending on when it does most of its growing, it is classified as either a summer or winter annual. Perennial weeds live multiple years but may behave similarly to annual species. Winter perennials flourish during the cool months and go dormant at the onset of summer heat. It is difficult to contain perennial species because they hold and store food reserves and nodes for subsequent root and shoot growth.

The final step is to consider herbicides. Pre-emergence and post herbicides are a useful management tool to prevent annual winter weeds from becoming established. Herbicides typically used in the spring for summer annual grass control will also provide control for most winter annual species. They will prove effective on some winter annual broadleaf weeds. Studies have shown that the application of these herbicides in mid-September has gained excellent control of annual bluegrass during the subsequent winter and spring. 

Identifying Weeds

Are you struggling with lawn weeds? You’re not alone. Step one in weed management is to identify your weeds. An annual is defined as a plant that germinates from seed, grows to maturity, produces seed, and dies within a 12 month period. However, most annuals only live for half a year at best, with a few exceptions.

Annual weeds will either be ‘summer annuals’ or ‘winter annuals’. Most winter annuals will germinate in late summer to early fall, survive through winter and grow quickly in the spring. They will produce seeds and die by late spring or early summer.

Since annuals die each year, they must come back the following year from seed. To ensure their survival, most annual lawn weeds produce an enormous amount of seed. Some plants can produce several hundred thousand seeds each year. 

Most lawn weeds don’t like competition, so a thick lawn turf is your greatest defense against lawn weeds. Focusing attention on weed control without building a dense turf is a guarantee you will have continued weed problems. For lawns in poor condition, it may take a couple of years of improvement before you see a significant reduction in lawn weeds. 

Weed Identification Examples

Corn Speedwell

– Spreading winter annual that germinates in the fall.

– Survives winter then grows considerably more by mid-spring.

– Dense mat-forming weed of thin or poor quality turf.

– Small rounded leaves, no more than half an inch in diameter.

– Small blue to purple flowers about just under half an inch across.

– Seed pods are heart-shaped.

Henbit

– One of the most common winter annuals.

– Square stems.

– Leaves positioned opposite each other on the stem.

– Slender, tubular, pink flowers at the tips of stems.

– Spreads by seed.

– Grows in moist soils and can reach heights of 12 inches by mid-spring.

Common Chickweed

– Winter annual that prefers moist sites.

– Tolerates cold weather well and can survive temperatures of near zero degrees.

– It will bloom all winter even when temperatures dip several degrees below freezing.

– Shallow root system makes it easy to be pulled up by hand.

– Mature leaves are approximately half an inch long with a smooth texture. These leaves fold up around the stem at night.

– Flowers grow in clusters on a long stalk, starting from the leaf axils. There are five white petals on each flower, but each petal is deeply lobed, giving it the look of ten petals.

Canada Thistle

– Perennial weed, classified as noxious.

– Soft green, deeply lobed, spear-like leaves.

– Purple pom-pom shaped flower produced in clusters at the top of the plant.

– If allowed to go to seed, the flower will become white and fluffy, much like the dandelion seed head.

Virginia Pepperweed

– Winter annual found throughout most of the US.

– It prefers dry soil conditions in full sun locations.

– The stems grow erect and are multi-branched.

– Leaves grow alternately on the stem.

– Almost all seeds germinate in late summer or fall.

Herbicides

Find a suitable herbicide that is powerful enough to kill weeds like corn speedwell but doesn’t cause damage to your lawn. Identify the grass varieties you have in your lawn to determine which herbicides won’t cause it harm. 

Pre-emergence weed control can lessen the growth of new lawn weeds. A pre-emergence herbicide is the solution when dealing with multiple unwanted weed growth. To control summer and winter annual weeds, application during spring and a second one in the early summer can limit the germination of the seeds left in the soil. The chemicals work by putting a herbicidal barrier on the soil surface that prevents any seed left from reaching the necessary conditions for their growth.

Tips For Using Post-Emergence Herbicides:

– Apply to actively growing weeds.

– Avoid mowing 24 to 48 hours before or after application.

– Irrigate 24 to 48 hours before application.

– Avoid irrigation within 24 hours following the application.

– Apply when the weeds are most susceptible, smaller weeds are easier to control than larger mature plants.

Of course, weed killers should only be used as a last resort. Herbicides can be dangerous, so be sure to read the entire label before using it, and always store the product according to the label’s instructions.

Don’t forget organic solutions. Use white vinegar for spot treating weeds. Pour white vinegar in a spray bottle and spray it directly on the weeds to kill them off. Vinegar is also effective against dandelions and crabgrass, which generally proliferates from spring to fall, but if you find some in your lawn during the winter, get that vinegar spray ready to make sure it doesn’t reappear in the spring.

Lawn Care

Most lawn weeds begin their germination and growth in winter. This is the perfect time to start an eradication program for a weed-free lawn through the spring and summer seasons. 

The best defense against weed infestation is the promotion of a dense turfgrass stand. Select a turf species adapted for the location (sun or shade) and intended use (low or high traffic). A turfgrass suited to its environment requires fewer inputs and will generally be less weedy. Maintain soil fertility, aeration, and moisture, mowing at the correct height to promote turfgrass growth. Preventing weed establishment and encroachment can be the result of a competitive turf. 

Generally, light is required for optimum germination of many annual weed species. By using a healthy turf canopy to reduce the amount of light that reaches the soil surface, you can reduce weed seed germination. It is vitally important to use the appropriate herbicides at the labeled rates when it becomes necessary to use chemical control. Read and follow the manufacturers’ directions and recommendations on the label.

Building a thick healthy turf, whether in warm or cool-season grass, is the best way to discourage winter annual weed invasion. You can use a pre-emergent in the fall to discourage seed germination. However, if you plan on overseeding, a pre-emergent will hinder your lawn seed from germinating as well in warm-season grass.

The best time for post-emergent herbicide use is in the fall or early spring. Weeds are still young and growing, making them easier to control. By mid-spring, the weeds have already hardened and are more tolerant of herbicides.

The primary way of preventing winter weeds from establishing is to build a thick, vigorously growing lawn. Mowing your grass at its tallest recommended height will help as well. Taller mowing heights promote deeper rooting and strengthens grass. However, warm-season grasses may experience problems with this and other lawn weeds until it breaks dormancy.

Opt for a reel mower. It has a superior cutting ability and, with its clean, even scissor cut, which seals the grass blade to hold in moisture and keep out disease organisms. It also yields a natural mulch by dispersing clippings in a fine spray that decomposes quickly.

If you want to reduce your lawn care issues for spring and summer, preventive actions must be carried out in the winter (ideally, during the latter part of the season). Try spreading a fresh layer of fertilizer. Some formulations can remove weeds and fertilize the lawn at the same time. Just make sure the product is compatible with the grass varieties in your lawn.

So, Do Weeds Die In The Winter? 

Do weeds die in the winter? Yes, they do. Unfortunately, death is not the end of the weeds. Those persistent weeds are determined to unfurl their leaves again come spring. Seeds are part of a cycle. Frost will do nothing to stop weeds from sprouting. Seeds can remain frozen for years and still remain viable.

Seeds are enclosed in a protective shell that makes them immune to spraying. They wait for the right conditions, including sunlight and correct temperature, to begin germination. As winter ends, their exposure to sunlight can start their life cycle and result in the growth of another batch of weeds. Seeds can be transferred by the wind, or they could come from your neighbors. Weed control is a year-long activity.