Staying On Top of Cool-Season Weeds

How should one weed in the winter?

Those with a strong attachment to their recliners might say ‘one shouldn’t,’ and leave it at that. I completely understand.  I have a strong bond with my yellow tufted chair that goes quite beyond love and is entering the realm of soul connection – particularly in the winter.

My yellow chair

However.

I submit to you three excellent reasons for throwing off that love affair and weeding during the winter months. One is harsh and somewhat personal, the second, perfectly factual and accurate, and the last, supported by Shakespeare himself.

– One –

Didn’t you made a New Year’s resolution that you would get more exercise?  Let’s kill two birds with one stone; or – according to PETA recently – feed two birds with one scone.

Something might as well enjoy the scones since that particular pleasure is no longer yours.

– Two –

There are a great deal of cool season weeds at their most vulnerable right now.  Vulnerable weeds are second only to dying weeds as the very best kind of weeds to own.

– Three –

If it were done when ‘tis done then ‘twere well it were done quickly.

I.e. it’s a nasty job that’s not going away – deal with it sooner rather than later because, in the words of another immortal poet,  April Come She Will.

Certainly we don’t want any damage to the garden, and I’m not advocating the sort of summer assault that starts with two gin and tonics and ends with a lidocaine patch. If you literally throw your weight around, you are in great danger of damaging your soil structure and the roots of plants you want to keep, so it is important to tread softly and carry a long hoe.

“But wait a minute!” I hear you scream.  “Weeding is for summer and warmth and children who got themselves grounded!  What is there to weed?”

Cool-season vs. warm-season weeds

There are cool-season weeds and there are warm-season weeds, and once you’ve been gardening for a while the appearance of either marks a turning of the seasons (even when you can’t feel it yet). 

For the purposes of this article, I’m not discussing those plants that fit under the classic definition of ‘weed’ – a plant you don’t happen to want growing where you find it. We’re going to focus instead on the ones you never want growing where you find them (unless you are a forager or a masochist, or indeed both).

Annual cool-season weeds germinate in the fall or early spring (early winter too if it is relatively warm) and finish out their lives by late June.  If they’re perennial they tend to be at their strongest during the cooler months.

winter weed seedlings

We can fight cool-season weeds, or if we’re messy and somewhat undisciplined, we can wait to have them replaced by warm-season weeds.

Warm-season weeds are what most people think of as weeds – purslane, dock, crabgrass, pigweed etc…  They germinate or come back to life when the weather warms, ending by the close of summer.  You may see tired and bedraggled remains of mallow or dock in winter, but they won’t start punishing you until late June. 

It’s always nice to have something to look forward to.

Set your sights on cool-season weeds

At this time of year we’re looking for cool-season annual weeds (such as chickweed, bittercress, deadnettle or henbit).  They can be lightly scraped or pulled whether or not the ground has frozen. 

Frozen soil makes scraping easier, though the work tends to be colder and the chair more inviting.  It’s best to cover that bare ground with cardboard and thick mulch when you’re finished to stop new weed seeds from germinating when conditions warm slightly.  It will also save you time in April.

Feeling adventurous? Perennial cool-season weeds such as wild garlic, dandelions and ground ivy may put on a lot of fighting weight in the winter, but extricating roots is impossible when the ground is frozen and is guaranteed to create a muddy mess when it’s not.  Nonetheless, the roots must be removed or smothered to kill the plant.

If you are feeling particularly adventurous AND patient, and the ground is not frozen, you can use a very thin trowel or tool to urge the taproots up. But beware, everyone’s feeling a little fragile in winter, including our weeds. If that root snaps in half, you’ve still got it and now you’re muddy. 

It’s better to scrape the top to weaken the weed and then use the cardboard/mulch method (thickly!) to smother it.  If it’s in your lawn, you’ll just need to wait until spring.

We all know what a dandelion looks like and can put two and two together when it comes to the telltale oniony leaves of wild garlic, but some of the others might just go by ‘weed’ in your Mid-Atlantic landscape.  Here are some of the more common cool-season weeds to aid your ID process.

I include the Latin names to make sure that my chickweed is your chickweed, and perhaps to help you make connections between some of the plants you love (Lamium maculatum – deadnettle) and the weeds you don’t (Lamium purpureum – also, awkwardly, deadnettle).

A few of our most common cool-season weeds

Common chickweed
(Stellaria media)

A succulent bright green plant that stays low to the ground at 3-6 inches. Opposite tiny leaves are pointed at the tip. Five-petaled white flowers.

Common chickweed – (Stellaria media)

Common chickweed
(Stellaria media)

The good news about chickweed is that it’s very edible.  The bad news is that it’s rampant. The earlier you harvest chickweed (either for the cook or the compost) the better.  Once it has begun to flower it holds onto the earth with greater tenacity, and pulling it up usually involves a lot of precious topsoil.  Once it’s gone to seed, it’s even tougher to shift and hundreds of seeds sow themselves liberally while you try to get it out of the ground gracefully.  Chickens love it if you have a flock – it’s a great winter forage for them.

Hairy bittercress
(Cardamine hirsuta)

This is a plant that starts life as a very low rosette made up of pinnate leaves.  If you haven’t scraped it, pulled it or otherwise gently ushered it out of this world by mid-April, it forms white flowers on the top of 4-6 inch stems which rapidly set seed and explode all over your lazy weeder’s hands in June.  An ounce of prevention is worth a pound of cure with this one – about 3 ½ pounds of seeds to be specific.

Hairy bittercress 
(Cardamine hirsuta)

Hairy bittercress
(Cardamine hirsuta)

Henbit (Lamium amplexicaule); and
Deadnettle (Lamium purpureum)

Henbit and deadnettle are related, and often confused, but the good news is that you probably don’t want either one of them so you needn’t get too scholastic about it. Both have square stems. Both have opposite leaves. Both have lipped flowers.

However, if you wish to positively ID the plant you’re culling, this is where Latin comes in handy. Dead nettle (L.purpureum) has a purple cast to the pointed leaves (bit of alliteration to aide memory) which climb the short spire-like stems and overlap each other, somewhat hiding the flowers.  Henbit’s leaves are frillier, flowers are showier, and well, it’s just girlier overall – but then it’s called henbit, not roosterbit.

Deadnettle (Lamium purpureum)

Deadnettle
(Lamium purpureum)

Ground Ivy (Glechoma hederacea)

Ground ivy is exactly what it purports to be: a tough, creeping, semi-evergreen, perennial groundcover that very quickly takes over – rooting at its nodes.  Leaves are opposite and rounded with scalloped margins.  Ground ivy has a very particular fragrance when it is crushed or mown – think bright, vegetative and sharp with a little onion chopped in.

Though it seems to come up easily, it’s a tough one to eradicate as the roots are brittle and happy to keep growing if you miss a couple.  In the winter it’s best to cardboard it.

Ground Ivy (Glechoma hederacea)

Ground Ivy
(Glechoma hederacea)

Garlic mustard (Alliaria petiolata)

Where do those tall, invasive stems of garlic mustard come from?  Well, they shoot up from rosettes that have settled in nicely the year before.

Garlic mustard is a biennial, so either find those rosettes and pull them or find the new seedlings and scrape those.  Leaves are rounded and textured at first, turning more pointed as they grow upward. 

If you’re not sure of your ID, pick a leaf and crush it between your fingers – the garlic scent is unmistakable. If you’ve missed it over the winter and see it flowering, pull it up at once – luckily it doesn’t hold to the soil too tightly.

Garlic mustard (Alliaria petiolata)

Garlic mustard
(Alliaria petiolata)

Mouseear chickweed
(Cerastium vulgatum)

Though the common names suggest it, Mouseear chickweed and common chickweed are not related.  Mousear chickweed has opposite, hairy leaves and stems, tends towards a tighter growth habit and always reminds me of miniature petunia seedlings.

It is also a perennial weed that roots at its nodes.  I’ve found that scraping it is very effective however – as long as mulch is applied where the weed once was.  Very quickly forms large, dense clumps.

Mouseear chickweed 
(Cerastium vulgatum)

Mouseear chickweed
(Cerastium vulgatum)

One last word about winter weeding

Chemical controls are futile, so don’t waste them, they’ll only run off.  Temperatures must be higher and plants in a state of strong, active growth in order to be affected.  What we’re seeing now is just the pre-show leading up to the main event in April and May.

Can’t get enough of the academics of it all?  Great resources include Weeds, Friend or Foe? by Sally Roth; Weeds in My Garden, by Charles B. Heiser, and online, https://extension.umd.edu/hgic/topics/spring-weeds .

___________________________________

A version of this article was originally published by The Frederick News Post and is published here with kind permission.


By | 2019-01-11T19:01:17+00:00 January 11th, 2019|

About the Author:

Marianne is the mother of two, wife of one and the voice of The Small Town Gardener. She gardens and writes from her home in the scenic (and exceptionally convenient) heart of Virginia's wine country.

One Comment

  1. David "Senior Citizen" Muns January 12, 2019 at 1:32 am - Reply

    Timely article! I weeded today. And yesterday. Probably tomorrow, too, unless we get a couple inches. Great reminder. And here’s another: Going to Jim’s for the luncheon?!

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