Weeds demand thick line and torque, so this guide prioritizes documented line diameter and motor power over weight.
Best String Trimmer for Thick Weeds
Trimmers with thick line and real torque for cutting heavy weeds, not just lawn grass.
Our top picks at a glance
Top Pick
EGO EGO Power+ ST1521SHomeowners with medium to large yards who want gas-level cutting power and hate rewinding trimmer line.
Runner-Up
Black+Decker Black+Decker 40V LST140CHomeowners who want more power than 20V tools without stepping up to a premium 56V system.
For Tough Edges
DeWalt DeWalt 20V Max DCST922BExisting DeWalt 20V Max battery owners who want a trimmer that shares batteries with their drills and saws.
For thick weeds, line diameter matters more than anything: the EGO Power+ ST1521S runs 0.095-inch dual line, the thickest in this guide, on a 56V platform with the torque to push it through heavy growth.
The picks, ranked
| Pick | Voltage platform | Cutting swath | Line diameter | Buy |
|---|---|---|---|---|
| Top PickEGO EGO Power+ ST1521S | 56V ARC Lithium | 15 inches | 0.095 inch dual line | Check price |
| Runner-UpBlack+Decker Black+Decker 40V LST140C | 40V Max | 13 inches | 0.080 inch | Check price |
| For Tough EdgesDeWalt DeWalt 20V Max DCST922B | 20V Max | 13 inches | 0.080 inch dual line | Check price |
Top Pick
EGO EGO Power+ ST1521S
15-inch Powerload head with automatic line loading.
Strengths
- Powerload head winds trimmer line automatically, eliminating manual spool rewinding
- Line IQ technology senses the load and feeds the correct line length without bumping
- 15-inch cutting swath with 0.095-inch dual line handles thick grass and weeds
- 56V ARC Lithium platform is shared across EGO blowers, mowers, and hedge trimmers
Limitations
- Heavier and pricier than 20V-class trimmers
- Best performance requires the larger 4.0Ah battery, which adds weight
- Overkill for small yards under a quarter acre
What owners report
Commonly praised
- Power that owners compare to gas trimmers, without fuel mixing or pull cords
- One battery finishes a typical suburban yard
- Quiet enough to use early in the day
Common complaints
- Old line can get stuck inside the head and needs disassembly to clear
- Reloading line is not as easy as the marketing suggests
- It feels heavy on the shoulders during long sessions
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Voltage platform | 56V ARC Lithium |
|---|---|
| Cutting swath | 15 inches |
| Line diameter | 0.095 inch dual line |
| Line feed | Powerload auto-wind + Line IQ |
| Head type | Bump-feed free, automatic |
Best for: Homeowners with medium to large yards who want gas-level cutting power and hate rewinding trimmer line.
Skip if: You are locked into the DeWalt or Milwaukee 20V battery platform, or you trim a small yard where a lighter 12-inch tool is enough.
Runner-Up
Black+Decker Black+Decker 40V LST140C
13-inch 40V trimmer with PowerDrive transmission.
Strengths
- 40V Max platform delivers more torque than 20V-class trimmers
- PowerDrive transmission transfers more power from motor to cutting string
- 13-inch cutting swath covers residential yards efficiently
- Power Command dial lets you control cut speed to extend runtime
Limitations
- Automatic feed spool advances line whenever it shortens, which can use line quickly
- Heavier than 20V models
- 40V battery platform is smaller than DeWalt's 20V ecosystem
| Voltage platform | 40V Max |
|---|---|
| Cutting swath | 13 inches |
| Line diameter | 0.080 inch |
| Line feed | Automatic feed spool |
| Drive | PowerDrive transmission |
Best for: Homeowners who want more power than 20V tools without stepping up to a premium 56V system.
Skip if: You need the widest swath available, or you want an automatic line-feed head.
For Tough Edges
DeWalt DeWalt 20V Max DCST922B
13-inch dual-line trimmer on the 20V Max platform.
Strengths
- Runs on the 20V Max battery platform, so existing owners can buy the bare tool
- 13-inch cutting swath with 0.080-inch dual line
- Variable speed trigger gives control for trimming versus full-throttle edging
- Lightweight and well balanced for extended use
Limitations
- Bump-feed head requires stopping and bumping to advance line
- Narrower swath than 15-inch class trimmers
- High-drain trimming benefits from a 5.0Ah or larger battery
What owners report
Commonly praised
- Strong cutting power with a responsive variable-speed trigger
- Good runtime, especially with larger 20V packs
- It folds for storage and uses batteries many owners already have
Common complaints
- The front end feels heavy, which tires the arms
- Several owners report the trimmer head wearing or breaking
- Retail ratings are noticeably mixed compared with rival trimmers
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Voltage platform | 20V Max |
|---|---|
| Cutting swath | 13 inches |
| Line diameter | 0.080 inch dual line |
| Line feed | Bump feed |
| Speed control | Variable speed trigger |
Best for: Existing DeWalt 20V Max battery owners who want a trimmer that shares batteries with their drills and saws.
Skip if: You need maximum cutting width for large properties, or you prefer automatic line feed over bump feed.
Questions, answered
Why does line diameter matter for weeds?
Thicker line resists snapping on woody stalks and carries more cutting energy. 0.095-inch line lasts noticeably longer in weeds than 0.065-inch line, which is designed for lawn grass.
Can a string trimmer cut brush?
Light brush, yes, with thick line. For established woody brush or saplings, a brush cutter with a metal blade is the right tool; no string trimmer here is rated for that.
Does higher voltage mean better weed cutting?
Generally yes for battery trimmers: higher voltage platforms deliver more torque to the head. 56V tools outmuscle 20V tools in thick growth, all else equal.