Potomac Lawn Professionals | Lawn Care Blog

How To Prevent And Treat Weeds In Virginia

Sow Thistles up against a wooden fence

Preventive Weed Control

Keeping your lawn healthy all season long is the best defense against weeds, and it is the most effective way to keep weeds from developing in the first place. Proper maintenance can help prevent seeds from being able to germinate in your yard’s soil, but there are also preventive weed control products you can use in your yard that will prevent weeds from popping up. Following the methods laid out in the sections below will give your lawn and gardens a great shot at staying weed free!

Install Mulch

Mulch Installation Header

Mulch naturally prevents weeds by creating a protective layer across the soil surface in gardens and flower beds. By covering all exposed soil that isn’t directly under your desired plants, you can prevent germinated weed seeds from being able to emerge. Virginia weeds commonly found in garden beds include spotted spurge, crabgrass, purple deadnettle, and more. 

Installing organic mulch prevents weeds by performing the following functions:

  • Blocks sunlight from weed seeds in the soil
  • Retains water so seeds can’t germinate
  • Adds nutrients to the soil for stronger plants
  • Physically blocks weeds from emerging 
  • Creates barrier to prevent seeds from reaching soil

Mow Higher

The importance of mowing your grass to the proper height

Keeping your grass slightly taller than normal (generally, 3 inches) is an easy and healthy way to prevent weeds from growing. If possible, make sure only the top 1⁄3 of your lawn is cut in order to maintain turf that is strong enough to fight against weeds. Properly mowing and maintaining a healthy lawn is always the best way to prevent weeds. 

Taller turfgrass can provide weed prevention in the following ways:

  • Blocks sunlight from weed seeds
  • Helps keep weed seeds out of the soil
  • Tall grass means deep grass roots, which means less weed roots
  • Thicker, taller grass can crowd-out weeds

Water Deeply

sprinkler maintenance service

Annual weeds often develop shallow root systems that dwell close to the soil surface. As water is introduced to the soil, the shallow weed roots are able to absorb it before it can even reach the deeper grass roots. Watering deeply means infrequent, longer sessions for each watering zone of your lawn. Watering only twice per week and allowing water to soak down to 8 inches deep in the soil should provide sufficient hydration for your grass. As grass roots get stronger and bigger, weed roots will struggle.

A few common weeds in Virginia that have shallow roots and would respond to deep watering treatments are the following:

  • Chickweed
  • Bittercress
  • Crabgrass
  • Henbit

Apply Fertilizer

chemicals and nutrients for the soil

As always, maintaining a healthy lawn is the best defense against weeds, and properly fertilizing your turf is a big part of that maintenance. Once the growing season begins, your lawn should receive between 6-8 fertilizer treatments throughout the year. Balanced, seasonally appropriate fertilizers will keep your lawn thick and nourished in order to withstand and choke out any weeds that are trying to emerge. 

  • Important – Check the NPK ratio (nitrogen, phosphorus, and potassium) to make sure your lawn receives plenty of nitrogen in early spring and not too much in summer, which can have damaging effects. Weeds often thrive in struggling lawns, and white clovers are notorious for overtaking nitrogen-deficient lawns. Click here to read about our fertilization services in Virginia.

Apply Pre-Emergent Herbicide

Control SPray

Pre-emergent herbicides are designed to prevent weeds from sprouting up through the soil in your lawn and gardens. These products work by creating a chemical barrier across the soil surface that will prevent the weed from sprouting once it meets that barrier.

Keep the following in mind when selecting and using a pre-emergent herbicide:

  • Apply in early spring and in fall in order to stop various weeds from sprouting after germination. 
  • Some pre-emergents are mixed with fertilizers, which would feed your grass while also preventing weeds.
  • Look for active ingredients like prodiamine, dithiopyr, or surflan, which are found in various name brand pre-emergents.
  • Effects may only last 6-8 weeks, and these products will not be effective against sprouted weeds.

Curative Weed Control

Once sprouted, weeds must be promptly treated or they will spread and overtake your yard before you even realize it. Weeds compete with your lawn and plants for nutrients, so removing weeds as quickly as possible is crucial to the overall health and appearance of your yard.

Mow/Trim Immature Weeds

Nutsedge in lawn

Mowing or trimming existing weeds that have not yet flowered will damage the plant, and it will prevent seed heads from developing and spreading seeds. The weed will become weaker every time it is mowed over or trimmed with a line trimmer, and it will die when it can no longer absorb adequate nutrition. This method is simple, but it will require multiple cuttings for lasting results. 

  • Important – Some weeds, like Virginia buttonweed, can tolerate mowing as low as ½ an inch, so this method will not be as effective for low-growing weeds. Also, a bag MUST be used when mowing over weeds in order to prevent the spread of clippings that may contain seedlings.

Pull Weeds By Hand

mulch install

Weeds with shallow roots can often be fully removed by hand. The most important thing to keep in mind when hand-pulling weeds is that the goal is to remove the entire root of the plant. If the root does not come up with the plant, the weed will simply regrow and continue to spread. 

Check out a few of our tips on how to effectively hand-pull weeds:

  • Grab weeds as close to the ground as possible
  • Wear thick gloves
  • Pull weeds when soil is soft/after irrigation
  • Loosen soil if it is hard
  • Pull weeds before they set seeds
  • Repeat task until weeds stop emerging

Dig Out Roots

monthly flower bed cleanup

For weeds with deeper or more complex root systems, digging out the plant is the best choice. Hand shovels, standing weeders, hoes, and other gardening tools can be used to dig down and around the entire root system of a weed for a more complete weed removal. Be sure to dig carefully around your desired plants so that you do not disturb their roots.

  • Important – Dandelions and violets are two common weeds in Virginia that often need to be dug out rather than pulled. Once these weeds mature, their roots are invasive and aggressive, and digging them out is most effective.

Apply Natural Weed Killer

Heart Lawn (1)

Chemical herbicides are generally safe and effective, but some people still prefer to use more natural products in their yards. Household products that contain a certain level of acidity can often be quite effective at killing existing weeds. However, you must always make sure to apply acidic treatments only to the weeds you hope to eradicate. Just like many chemical herbicides, homemade remedies will not be able to tell the difference between your desired plants and unwanted weeds.

The following natural weed killers can be applied separately, or they can be combined in a spray bottle for a stronger effect:

  • Vinegar
  • Vegetable Oil
  • Boiled Water
  • Hand Soap
  • Baking Soda
  • Salt

Apply Post-Emergent Herbicide

direct weed control sprayed onto a dandelion

If weeds have completely overtaken large sections of your yard, a post-emergent herbicide is the way to go. These products are designed to kill existing weeds and their roots in order to take care of the problem permanently. When selecting a product, look for ingredients named 2,4-D and dicamba to treat broadleaf weeds, and look for glyphosate to treat grassy weeds.

  • Important – Some weed killers are of the selective variety, meaning they only target specific types of weeds and do not affect others. Make sure to consult with an expert if you are unsure about the type of herbicide you are using, or call Potomac Lawn Professionals at (703) 533-5296 for premium weed control treatments in Virginia!

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