Mares Tails Weeds: What They Are and Why They Drive Gardeners Crazy
Mares tails weeds — also written mares-tail or mare’s tail — are a name that gardeners use for two different troublemakers. One is horsetail (Equisetum species), a primitive, wiry, rhizome-spreading plant that looks like a tiny green broom. The other is marestail or horseweed (Conyza canadensis), a tall, weedy annual that produces lots of wind-blown seed. Both can be persistent, but they behave very differently and need different approaches. If you’ve ever battled a patch that keeps coming back no matter what you do, this guide is for you.
How to Tell Them Apart
Identification is the first step toward control. Here’s how I tell them apart in my own beds and lawn.
- Horsetail (Equisetum) — looks like hollow, segmented green stems, often in dense clumps, with a rough texture. It spreads via underground rhizomes and favors wet, compacted, acidic soils.
- Marestail / Horseweed (Conyza canadensis) — a tall, branched, fuzzy-looking annual that produces white seed tufts in late summer and fall. It starts from seed and can colonize bare soil, cracks, and disturbed ground.
Why They’re So Difficult to Get Rid Of
Both types are persistent, but for different reasons. Horsetail has a deep network of rhizomes that can regrow from tiny fragments. It’s been around since the dinosaur era and loves poor, wet soil where many garden plants struggle. Marestail is a prolific seed producer with seeds that float on the wind, germinate in thin soils, and tolerate herbicide resistance in some areas.
Conditions That Favor Mares Tails Weeds
- Poor drainage and compacted soil — great for horsetail.
- Acidic soils — horsetail tolerates low pH better than many plants.
- Disturbed ground, unmulched beds, and thin lawns — perfect for marestail seedlings.
- Seasonal timing — marestail seeds germinate in spring and late summer; horsetail sends up shoots in early spring and continues through the season.
Practical Control Strategies I’ve Used
After more than a decade of gardening I’ve learned there’s no single magic cure. What works best is a combination of persistence, cultural changes, and targeted treatments. Here are techniques that actually work.
Non-chemical methods that help a lot
- Repeated Cutting or Pulling — For horsetail, repeatedly cutting shoots flush with the soil weakens the rhizome over time. Do it every week or two during the growing season. For marestail, pull or hoe seedlings before they seed.
- Digging and Rhizome Removal — If you have a small patch of horsetail, dig deeply and remove as many rhizome pieces as possible. Be prepared: it often takes several digs over multiple seasons.
- Smothering and Solarization — Cover a bed with heavy-duty black plastic or cardboard and leave for several months in summer. Solarization can weaken both horsetail and marestail, especially in full sun.
- Improve Drainage and Soil Structure — Amend compacted, waterlogged soil with organic matter, raise beds, and install drain paths. Horsetail thrives in wet, compacted conditions — change the environment and you win half the battle.
- Mulching and Dense Planting — Thick mulch and vigorous groundcovers shade out seedlings and reduce wind-blown marestail establishment.
When to consider herbicides (and how to use them safely)
I prefer non-chemical methods first, but when an infestation is severe I use spot treatments responsibly. Always follow label instructions and local regulations. Some practical tips:
- Glyphosate works as a non-selective option for horsetail and marestail. For horsetail, late-summer to early-autumn applications are most effective because the plant is moving carbohydrates to its rhizomes, which helps translocate the herbicide.
- For marestail, treat rosettes in spring or young plants before they bolt. Multiple treatments may be needed for seedbanks.
- Look for brush-specific or systemic formulations for tough horsetail stands; products labeled for perennial rhizome systems will perform better than quick-contact options.
- Spot-treat only the affected plants to preserve beneficials and reduce chemical use. Wear gloves and eye protection and keep pets and children away until dry.
“I battled a clay-capped horsetail patch for three seasons before I finally gave it a one-two punch: deep digging in spring, improved drainage, and two late-season glyphosate spot-treatments. It’s not perfect, but the patch shrank to a few shoots the next year.” — Your neighborhood gardener
Prevention and Long-Term Maintenance
Getting mares tails weeds under control is part tactic, part patience, and part prevention. Here’s how I keep them from roaring back.
Practical long-term steps
- Fix drainage and raise beds where horsetail appears.
- Add lime if your soil is very acidic (test first). Horsetail prefers low pH, so neutralizing acid can help reduce vigor.
- Maintain a thick, healthy lawn to outcompete marestail; overseed thin areas and fill bare patches promptly.
- Hand-pull or hoe marestail seedlings in spring and early summer before they produce seed.
- Keep mulch layers topped up and plant dense groundcovers or shrubs to shade exposed soil.
When to Call a Professional
If you have a large, deep-rooted horsetail infestation in a landscape or hard-to-reach place, it may be worth hiring a licensed professional. They can assess drainage solutions, safely apply herbicide where permitted, and recommend long-term landscape fixes. For marestail that’s developed herbicide resistance on a large scale, professionals have tools and rotation strategies that help.
Final Thoughts from My Garden
Mares tails weeds are stubborn, but they’re far from unbeatable. Identify whether you’re dealing with horsetail or marestail, change the conditions they like, and be consistent. Over time you’ll reclaim beds and lawns with a mix of persistence, smart cultural fixes, and carefully targeted treatments. In my experience, the satisfaction of finally shrinking a patch of horsetail or stopping the annual onslaught of marestail seeds is well worth the effort.
If you want, tell me which one you’re dealing with and I’ll give a tailored plan for your yard — soil type, photos, and season help a lot.
