Cold winter weather is good at killing off plenty of garden plants, but is it enough to kill weeds?
Do weeds die in winter? It’s a common question, but unfortunately, there’s no OSFA answer: some weeds die and some don’t.
In this article, we’ll have a good look at which weeds will die in winter, and which ones just go dormant. Then we’ll look at tips and tricks for weed control before and after the winter.
- What is a Weed?
- Do Weeds Die in Winter?
- Which Weeds Don’t Die in Winter?
- How Can I Beat the Weeds?
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- Some weeds die in winter, some go dormant, others grow through winter.
- Many weeds leave seeds behind at the end of summer that stay dormant through winter and sprout in the spring.
- Completely eradicating weeds is impossible. Instead, you need to choose a management approach.
- Weeds can be managed with or without sprays. Unfortunately, neither option provides a quick or long-lasting fix.
- Little and often is the trick! Stay on top of them with manual removal to avoid the formation of deep tap roots and seeds spreading.
What is a Weed?
In layman’s terms, a weed is simply a small (or big) plant, often a herb, that’s growing where you don’t want it.
Some weeds can cause health issues for pets and animals, while others take over or don’t flow with the aesthetic you want for your yard.
Different people actually have different concepts of what weeds are depending on their threshold for the wild, unkempt look.
Many people appreciate herbs such as dandelion and clover for the food they provide pollinators, and the health benefits for humans that they can provide when prepared as a tea.
However, there are some weeds that most would agree are best kept under control:
- Invasive weeds are introduced species that have little or no competition and can therefore over-run native species.
- Noxious weeds are species that the federal or state government has declared to be injurious to health or physical well-being.
Identifying Your Weeds
Before you can create a plan of attack, it helps to understand what types of weeds you’re dealing with in your garden:
These are weed species whose life cycle consists of one season. They grow quickly, flower and set seed in a short space of time, and they seem to pop up almost anywhere.
Despite their short life, they’re hardy; the seeds of many annual weeds can lie dormant for several years until conditions are right, and they often germinate at lower temperatures. This means when spring comes, they’ll push through before other garden plants.
Some examples of annual weeds include:
- Common nettles
You guessed it!… biennial weeds complete their lifecycle in two years rather than one year. Biennial weeds flower in the late summer or fall, but seeds don’t emerge until the second growing season.
Some of the common biennial weeds:
- Field bindweed
Perennial weeds can last for many seasons, by sending up shoots from their underground root system. They’re tough, and compared with annual and biennial weeds, they’re often highly resistant to common herbicides.
In short, they’re a real menace! And their ability to reproduce via both seed and their creeping underground stem systems makes them super challenging to control. (If you don’t remove the entire root, the plant can reproduce by sending up a shoot from the remaining root.)
Some common perennial weeds include:
- Poison Ivy
- Japanese knotweed
- Johnson grass
- Quack grass (common couch)
Do Weeds Die in Winter?
Let’s find out…
Most weeds don’t like the cold any more than the rest of your garden plants, and low temperatures do effectively kill the vegetation of many common weed species.
But, because your garden seems to have fewer weeds during winter than summer, or because they spread more slowly, don’t think you’ve won the weed war: lots of them are good at playing dead, and when the spring comes along… Bingo! There they are again!
Why? Because they plan ahead. They store up resources to help them through their winter dormancy, then come back as large as life once the cold weather has passed.
And if they’re the flowering variety, they drop their seeds during late summer and fall, where they lie happily dormant through the cold months.
Which Weeds Don’t Die in Winter?
Does snow kill dandelions? No. Dandelions, Canada thistle, chickweed, prickly purse and annual bluegrass are all species that continue to plague gardeners during winter.
And if the season is a milder one, even broadleaf weeds might survive the cold.
So, what month do weeds stop growing? And what temperature kills weeds?
As winter approaches, weed growth will generally slow. So, from December through to February, you can expect less weed growth.
As a rule of thumb, if the night-time temperatures drop below 28° for more than four hours, the above-ground vegetation of most weeds will die off.
Having said that, some of the tough guys such as annual bluegrass, can even survive up to 6 weeks of snow and ice!
The challenge is that while other plants are dormant, these weeds will take advantage of reduced competition and flourish! On the positive side, they may be easier to spot and get rid of during winter, especially if the rest of your lawn and garden has yellowed or died back.
As mentioned above, many weeds drop seeds before the cold arrives, thereby ensuring that they’ve supplied you with a season’s worth of headaches once the weather warms up.
How Can I Beat the Weeds?
We all know that ‘prevention is better than cure’, and your garden is no exception to this rule.
Having a plan of attack is super important. A lawn care calendar is a great tool when it comes to planning and staying one step ahead of lawn and garden weeds.
There are different options available for weed management and each has its pros and cons.
We’ve listed them here so have a peruse and decide which approach to go with.
The Spray-Free Options
There are a few different things you can do to naturally manage weeds without resorting to spraying.
Unfortunately, there is no quick fix. Instead, long-term sustainable weed control requires staying on top of weeds before they become a real problem.
If weeds have become a problem to the point that they have completely overrun your yard, these are your options:
Water deeply to soften the soil and then use a fork to loosen large weeds from the ground so that you can pull them out with their roots intact. You can focus on just the biggest, most problematic weeds and then hoe the rest.
Regular hoeing will prevent any new weeds from establishing roots or getting a chance to flower and seed. The hoed weeds will then die and return their nutrients to the soil – you don’t even need to remove them!
If you are targeting your lawn, re-seeding with plenty of good quality grass seed should mean that there is no space for weeds to return. Keeping your lawn dense and healthy is the secret to keeping weeds at bay.
The best way to prevent weeds from establishing themselves in your garden beds is to avoid leaving any bare soil exposed.
Instead, plant ground cover plants like creeping thyme, and keep the soil surrounding ornamentals well mulched with around two inches of shredded leaves, grass clippings, aged compost or wood chip.
Cover with Black Plastic
If you have an area of your yard that is completely overrun but manual removal isn’t possible, cover the area with black plastic sheeting weighted down with bricks.
Leave the area for a few months, ideally through the spring when most seeds will be trying to germinate.
The heat of the sun will raise the temperature under the plastic and kill any weeds underneath. You can then hoe and re-seed if you want the area to be lawn, or mulch and re-plant with ornamentals.
Overseed Your Lawn
You also have the option of overseeding a weedy lawn without actually doing anything to the weeds per se.
Instead, hand pull the largest and most obvious, then mow your lawn as short as possible, water deeply, sprinkle with a layer of potting mix, fertilizer and grass seed, and wait for the magic!
This is one of the best ways to control weeds on your lawn in winter.
If weeds haven’t completely overrun your yard and you just need to stay on top of them, use these tips:
Keep Things Tidy
Keep your lawn mowed to the appropriate height for your grass type, season and the type of weed you are trying to control.
For example, during summer, a slightly longer lawn has the advantage of being healthier and more likely to out-compete weeds.
A longer lawn is also more likely to shade out crabgrass and prevent it from becoming a problem.
The opposite is true if you have weeds in your lawn that have just flowered or gone to seed.
Then, you really want to be mowing your lawn a little shorter with the catcher on to remove all of the flowers and seed heads before they get a chance to disperse.
In this way, you can reduce the seed bank of your yard and lessen the arrival of new weeds.
Not sure what type of mower would be best for you? Our guide to different types of lawn mowers will help you select one that suits your needs and your budget.
Be Smart About Watering
One of the most underrated skills of gardeners is knowing smart watering strategies, especially if you’re dealing with a new garden.
When you water every bit of soil in your space instead of just your plants, it means you’re also watering the weeds and helping them grow.
Using soaker hoses or setting up a direct watering system that goes straight to the roots of plants will do wonders to help you achieve a weed-free space.
Brush Up on Your Weedy Knowledge
Learn about the weeds specific to your yard and their lifecycles.
Weed management is really all about timing and doing what you can to remove them before they go to seed.
The easiest way to manage the weed load of your yard is to weed frequently in the spring when many of the young weeds are emerging.
Little and often will prevent them from getting established and reproducing.
Read my guide to the most common lawn weeds to help with this.
The Chemical Spray Option
Note that there are two broad categories of herbicides: pre-emergent and post-emergent.
Post-emergent sprays will not kill seeds so there is no use using them when the plant is not in its active growth phase or has already flowered or spread seeds.
Pre-emergent sprays do kill seeds and prevent them from turning into the weeds you hate, but it requires the seeds to try and start germinating first.
The success of this spray also depends on the right amount of rain and sun, so timing is crucial.
Neither option is suitable for winter. Using the wrong type of herbicide at the wrong time of year will just increase the supply of seeds in the soil, known as the seed bank, and make the problem worse!
Chemical sprays should be used as a last resort. At the very least, make sure you’re using the right kind of weed killer for the job.
When Should I Spray Weeds?
Assuming you’ve decided to take this route, timing is key.
Applying a dose of pre-emergent herbicide in spring will help to prevent summer annuals from appearing.
Applying another dose of pre-emergent herbicide in fall will help to prevent winter annuals from appearing.
And for the sneaky ones that still somehow manage to get through, use a dose of post-emergent herbicide to knock them off before they flower and drop seed.
If you’re tackling weeds in the lawn, you might choose to use a targeted broadleaf spray – this will kill off weeds without killing your grass at the same time.
Tips for Weed Spraying
Here are a few simple things to remember when spraying weeds in your garden and lawn:
- The temperature needs to be 40°F or above for the spray to be effective.
- Water the soil 24 – 48 hours before you apply the herbicide.
- Don’t water the soil for 24 hours after applying the herbicide.
- Don’t apply herbicide on a windy day – overspray can kill other plants in your garden.
- Be careful about letting pets and children near the sprayed area during and after spraying.
Can I Get Rid of Weeds Completely?
No. Mother Nature loves diversity, and there will always be opportunistic species ready to take advantage of a cozy niche in your yard.
Weed seeds travel on the wind, they are spread around on shoes and in pet fur, and they creep under fences.
Maintaining some management practices like the options listed above is the only way to keep them at bay. And winter time is no season for slacking off! For more information about caring for your lawn in winter, click here.
In conclusion, most weeds don’t die in winter, but instead go dormant or have seeds waiting underground for the warmer weather to arrive.
While some weeds are a menace, with a comprehensive prevention plan, you can win the battle.
And there’s nothing quite like the satisfaction that comes from a morning’s work pulling weeds!
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