Spider grass can be a pesky weed that invades lawns and garden beds. With its thin, wiry stems and ability to spread aggressively, spider grass often becomes a nuisance that is difficult to control. However with the right techniques and persistence you can get rid of spider grass for good.
What is Spider Grass?
Spider grass refers to two common perennial grasses
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Aristida ternipes – Also known as wiregrass or spidergrass, this clumping grass has fine, threadlike leaves that resemble spider legs. It spreads via seeds and lateral roots.
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Liriope spicata – Also called creeping lilyturf or monkey grass, this grass has wider, straplike leaves. It spreads through underground rhizomes and tubers.
Both grasses are very hardy and can tolerate drought, poor soil, and partial shade. Unfortunately, these same traits also make them challenging to eradicate.
Why Get Rid of Spider Grass?
Left uncontrolled, spider grass can quickly take over gardens and lawns. Here are some reasons you may want to remove it:
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It’s aggressive and crowds out desired plants. The lateral roots and rhizomes allow it to spread rapidly.
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The thin, wiry stems look unattractive in ornamental gardens.
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It creates bare patches in lawns, as the sparse foliage doesn’t fill space well.
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The shallow roots don’t hold soil well, leading to erosion issues.
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The light, airy texture dries out quickly and turns brown in drought or cold weather.
Controlling spider grass takes persistence, but doing so will allow your other plants to thrive.
Manual Removal Methods
For small infestations, manually digging up the grass may be effective. Here’s how:
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Use a shovel, trowel, or soil knife to dig under the plant and lift it out. Try to remove as much of the root system as possible.
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Shake or rinse off soil from the roots so you remove any remaining plant fragments.
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Fill in the holes with fresh soil or mulch to discourage regrowth.
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Check the area regularly for new sprouts emerging from leftover roots and remove them promptly.
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Repeat digging whenever you see new growths until the infestation is gone. This may take several seasons.
Manual removal works best when the soil is damp after rain or watering. Take care to minimize soil disturbance, as this can lead to further spread.
Smothering with Mulch or Plastic
You can smother spider grass using a thick layer of mulch or plastic sheeting:
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Cut the grass stems back as short as possible.
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Water the area thoroughly.
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Cover with 4-6 inches of mulch like wood chips, straw, or pine needles. Or use heavy black plastic.
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Overlap the edges and weigh down the material so it doesn’t shift.
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Leave the barrier in place for at least one growing season. The lack of light and smothering effect will kill the grass over time.
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Check regularly for any new sprouts at the edges and stay vigilant in subsequent seasons.
This low-effort method works best for large areas. The drawback is you’ll also kill any desirable surrounding plants.
Applying Herbicides
Herbicides that contain glyphosate (such as Roundup) are very effective at killing spider grass:
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Confirm the product is safe to use in your location. Never apply near water sources or edible gardens.
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Cut the grass back to encourage new growth. Healthy, growing plants absorb herbicides better.
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Mix the herbicide according to label directions and apply it carefully to the foliage on a calm, dry day. Avoid drift onto other plants.
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It may take several applications spaced 1-2 weeks apart before the grass dies completely. Be patient and persistent.
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After the grass dies back, remove the dead remains to tidy up the area. Monitor for regrowth.
While fast and powerful, herbicides have drawbacks like toxicity and harming nearby plants. Use them judiciously as a last resort if manual methods fail.
Solarization for Garden Beds
Solarizing infested garden beds can control spider grass using the sun’s heat:
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Mow down and clear out the area completely.
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Water thoroughly, then cover with clear plastic sheeting, securing the edges well.
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Leave the plastic in place for 4-6 weeks over summer. The heat under the sheet will cook the grass.
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Uncover the area and prepare the bed for replanting. Watch for any resprouting.
Solarization is eco-friendly but only works for small, defined beds, not lawns. It also kills beneficial microorganisms in the soil.
Preventing Spider Grass Growth
Once you’ve succeeded in removing spider grass, follow these tips to keep it from returning:
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Maintain healthy turf or dense garden plantings to crowd out potential weeds.
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Improve drainage issues and avoid overwatering, as spider grass thrives in moist soils.
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Use mulch, landscape fabric, or gravel as weed barriers in susceptible areas.
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Be vigilant and remove any new sprouts quickly before they get established.
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Clean equipment after working in infested areas to avoid spreading seeds or plant parts.
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Consider planting competitve groundcovers like vinca minor as an alternative to grass in problematic spots.
With persistence using cultural, mechanical, and chemical controls, you can get rid of spider grass for good and reclaim your lawn and garden. Don’t let this stubborn weed take over your outdoor space!
Frequently Asked Questions about Controlling Spider Grass
Here are answers to some common questions about managing spider grass:
What’s the easiest way to get rid of spider grass?
For most cases, applying a glyphosate herbicide like Roundup is the quickest and most effective solution. The key is repeatedly treating regrowth until the infestation is completely eradicated.
Does vinegar kill spider grass?
Household vinegar is not strong enough to kill spider grass. High-concentration horticultural vinegar can provide control, but it may take several applications. It also could harm desired plants through soil contamination. Herbicides are usually more effective.
Will digging up spider grass get rid of it permanently?
Removing spider grass by hand can eliminate a small patch, but you must dig deep and remove all the root fragments. Any remnants left behind will likely resprout. Follow up frequently with additional digging of any new growths.
Does boiling water kill spider grass?
Boiling water will damage and kill any spider grass it directly contacts. But it doesn’t affect the roots, so the grass often resprouts afterwards. It’s not a practical treatment for large infestations.
Will grass seed grow in spider grass?
Typical lawn grass seeds will struggle to germinate and establish within dense spider grass. It’s best to eliminate the spider grass completely using herbicides or solarization before reseeding an area.
What can I plant to replace spider grass?
Good alternatives include groundcovers like dwarf mondo grass, ajuga, sedums, or liriope. Annuals like sweet alyssum and periwinkle also help crowd out spider grass. For lawns, improve drainage and fertility to encourage healthy turf.
How do I stop spider grass from spreading?
To stop its spread, diligently dig out new growths as soon as you see them. Also address any conditions like excessive moisture that facilitate its growth. Maintain healthy plantings and use barriers like landscape fabric to make areas less hospitable.
Eliminating this stubborn weed takes patience and persistence, but it can be done! With a little biological and chemical warfare, you can get the upper hand against spider grass invasion.