While a healthy lawn can fight off most weeds, there are some particularly aggressive annual weeds that spring up early and race to get more ground than your own lawn’s turf. Whenever my warm-season grasses are slow to grow or where bare spots have appeared in cool-season yards, the hairy bittercress weed can pop up fast.
If this pesky weed grows in your lawn, you are left with several options to get rid of it. The severity of the infestation, your specific turf grass, and the time of year the weed is growing can all influence what you should do about it. This article covers the best herbicides to use to eliminate hairy bittercress weed from your lawn, along with other annual weed seeds.
How To Get Rid Of Hairy Bittercress
Although an unmaintained lawn may suffer a severe infestation of bittercress, it is technically an edible weed in the mustard family and can be harvested and enjoyed from an organic, toxic chemical-free lawn. If you have already treated your lawn with something that makes harvesting the flower heads unsafe, then there are several chemical weed control methods that can kill on direct contact and eliminate any unwanted plant material from your yard.
To prevent an outbreak of this weed in the spring, you can use pre-emergent weed killers found in some yard improvers like Scotts turf builder weed and feed. If you live in a cool climate with mild winters, then hairy bittercress weed has a good chance of growing alongside your winter turf. As you feed it, the weeds will grow unless the herbicide is added to prevent these common weeds from germinating.
If this winter annual starts to grow in the spring, usually when winters are harsh, then you may not be able to count on a pre-emergent herbicide to prevent the germination of this weed. If that happens then, the solution is simply to use a post-emergent herbicide to wipe out hairy bittercress weeds and other common spring weeds before they grow big and establish deep roots.
Treatments done when warm-season turf is still dormant can wipe out annual spring weeds in late winter before your lawn wakes up.
If you have turf grass that may suffer herbicide injury while initiating broadleaf weed control in established lawns, then the option of manual removal is available. Bittercress will resprout from a damaged taproot, and like all mustards, the root is deep and strong. A long, slim weeding tool can be used to remove a range of weeds, but it is important to dig them up right after the germination of weed seeds. Healthy weeds are difficult lawn weeds to remove by hand.
Hairy Bittercress Herbicides
Cardamine Hirsuta L. is a broad-leaf annual weed that has white flowers and springs up when winter warms up. In mild winter climates, these edible weeds can be present from late winter to early summer. Once the temperatures begin to rise, most difficult winter weeds will die off, and bittercress is no different.
If it is spring and your turf grass is having problems growing because of this nuisance weed, there are plenty of herbicides to choose from. To kill this short-lived weed, you can choose from pre-emergent, post-emergent, and even non-selective broadleaf herbicides, whichever fits your lawn’s needs. Below are some common choices and what they do to hairy bittercress.
| Herbicide | Type | Effects |
| 2-4 D | Post-Emergent | Uncontrolled Growth |
| Triclopyr | Post-Emergent | Uncontrolled Growth |
| Clopyralid | Post-Emergent | Uncontrolled Growth |
| Dicamba | Post-Emergent | Uncontrolled Growth |
| MCPP | Post-Emergent | Uncontrolled Growth |
| Gallery | Pre-Emergent | Disrupts Enzymes needed for Germination |
| Ronstar | Pre-Emergent | Disrupts Enzymes needed for Germination |
Pre-Emergent Herbicides
Stopping problematic weed species before they break ground is an effective strategy but only one you can capitalize on once you know these weeds exist in your lawn. If you try to guess what weeds you will encounter, you may be using more product on your property than is necessary. After the first year of rampant weed growth, you will know exactly what to stop from germinating the following spring.
Most pre-emergent herbicides should be used within 40 days of when seeds are expected to germinate. If in the fall, you noticed seed heads of annual weeds spreading seeds, then you will want to lay a pre-emergent. This will reduce the number of weed seeds that successfully germinate and can help keep annual weed populations from growing worse each year and choking out your turf.
Once the herbicide is spread, you will want to water it in so it can penetrate the soil and reach the waiting seeds.
Post-Emergent Herbicides
broadleaf variety of weed pests seems to be the most common class of undesirable weeds, and that has produced a range of herbicides designed just for them. While heavy-duty chemicals may be needed for shrubby woody perennial weeds, hairy bittercress can be wiped out with significantly weaker chemicals. The key is applying it at the right time and using the correct application rate for the weeds you are fighting.
Most herbicides can be sprayed onto foliage after weed emergence, and within a few days to a week, the weeds will be dying. This is effective for most types of broadleaf weeds and can be done on common lawn types without any turf damage. Always follow the instructions and water in the herbicides or let dry for the directed timeframe. Improper use of herbicides can burn lawns and hurt sensitive turf grasses.
Preventative Tips to Control Hairy Bittercress
A penny of prevention is worth a pound of cure, and this is no truer than in our lawns. If you have had problems with bittercress in the past or are noticing little weeds with white flowers growing in frequency, then you should start taking action immediately. Below are some of the best prevention tips I have come across.
Check Early in the Spring
As soon as the deep cold of winter passes, the warming soil can lead to the germination of winter weeds. By the time you get out on your lawn for the spring, you may already have a bittercress outbreak. Getting out and checking the ground as soon as you know the soil will be warming up can give you a head start against early spring annuals.
Weed Landscape Plants
Broadleaf weeds often make their way into our lawns through our garden beds and landscaping plants. While we are likely to mow our years frequently, preventing seed heads from forming, the plants outside of our mower’s scope of cutting can allow weeds to take root underneath. If you are not on top of these weeds, they may spread into your lawn with wind and pets. Weed around all plants when the winter is over to keep late spring and summer weeds from popping up.
Use Mulch
Any area that is not going to have grass seed or sod placed down should be covered. Weeds tend to accumulate and sprout best where the earth is bare, and there is little to no competition. Turf hindrances like high traffic and compaction do not seem to affect weeds as badly as grass. Keep weeds off bare soil by placing several inches of mulch that can completely stop weed seeds from germinating.
Mow Frequently
The number one way to keep weeds out of your lawn is to maintain your lawn at a height where only your turf can thrive. Each grass type has its own unique growing quirks, and knowing your turf can help you grow grass weeds can’t thrive in. Warm-season grasses that are the most susceptible to the early growth of bittercress can beat it out later by mowing low 2 to 3 inches.
Doing this all spring will reduce the number of seed pods broadleaf weeds can produce and spread.
Fertilize Properly
Using the right fertilizer at the right time is important, or you may feed weeds instead of your grass. If you use a quick-release fertilizer in the spring, then weeds like bittercress will absorb the nutrients while your turf is still dormant. As your grass wakes up, the weeds will be towering above and dropping seeds as fast as they can.
Using a slow-release formula will not benefit the early-season weeds but will be available when your warm-season grass starts to actively grow in the late spring heat.
Is Hairy Bittercress Invasive?
Broadleaf weeds can become invasive if they are left unchecked or if conditions in your yard are wildly favorable for weed production. Hairy bittercress will invade an area and can outcompete and choke turf that is slow to grow. Usually, this weed will grow in areas of the yard where nothing is thriving and try to establish on bare earth.
Once established, bittercress will spread quickly but starts to retreat as the temperature increases in late spring. Most of these plants have a very deep taproot that makes hand-pulling difficult or impossible, adding to the invasiveness of this species. Because it is a small weed, it can hide easily under other plants and produce tons of seeds.
Fortunately, it is an annual, so no matter how bad it is one year, if you prevent new seeds from dropping and wait for the summer temperatures to arrive, you can nip this problem in the bud and kill bittercress with the correct herbicides.
Last update on 2024-10-06 / Affiliate links / Somes Images and Data from Amazon Product Advertising API