5 Best String Trimmers for Thick Grass (2026)

The EGO Power+ ST1521S is the cordless string trimmer for homeowners who have committed to battery-powered yard tools and need a kit that performs on established grass rather than just thin new growth. Coming with the 2.5Ah battery and charger at $298, this is a complete functional solution rather than a tool that requires separate battery investment to start working. The 15-inch cutting swath handles most residential trimming effectively — along fence lines, around garden borders, and edging driveway pavement. EGO's Power+ system runs on the same 56V battery platform as their mowers, blowers, and chainsaws, so existing EGO battery owners are already set, and new buyers are investing in a system with the strongest ecosystem in cordless outdoor power equipment. That compatibility is a long-term consideration worth factoring into the purchase: the battery purchased here also runs a future EGO mower. For thick grass specifically, the ST1521S outperforms sub-$200 cordless trimmers because the motor sustains cutting speed through resistant material without the bog that limits cheaper platforms. The 2.5Ah battery handles a typical residential trimming session on a single charge — front and back yard boundaries on a standard suburban lot without needing to stop and recharge. The automatic line advancement occasionally fails to advance cleanly in very dense or tangled growth, which is a real limitation for properties with persistent heavy overgrowth rather than standard maintenance. For those situations, a heavier-gauge line or the 16-inch variant handles the load better. For regular residential maintenance, the ST1521S covers the task without gas, without an oil change, and without cold-start frustration.

Expand-It compatibility — add edger, blower, cultivator attachments 4.0Ah battery delivers gas-replacement power Battery-only ecosystem — 40V batteries not cheap Heavier than 20V trimmers with battery Compared to the Toro Flex-Force 60V Brushless 14/16-Inch Cordless String Trimmer with 2.5Ah Battery at $190 on this page, the RYOBI RYOBI 40V Expand-It Cordless String Trimmer Kit costs $10 more but may offer additional features or brand support worth considering for serious users.

60V brushless motor for gas-equivalent cutting power 60V battery not cross-compatible with Greenworks or other brands Keep in mind: heavier than 40v models. At $190, the Toro Toro Flex-Force 60V Brushless 14/16-Inch Cordless String Trimmer with 2.5Ah Battery costs $10 less than the RYOBI 40V Expand-It Cordless String Trimmer Kit ($200) on this page, making it the stronger value pick if the spec differences fit your needs.

Corded 6.5-amp power is the BLACK+DECKER's argument on a thick-grass page — unlike battery trimmers that fade as charge depletes, the corded motor maintains consistent cutting force through the entire session. The 14-inch swath handles most residential lawn edges in fewer passes than narrower 10-12 inch models, and the auto-feed line advance means less stopping to manually extend line mid-session. At $59.00 it's positioned far below the RYOBI 40V ($199.99), Toro 60V ($190.00), EGO ($298.00), and Makita ($298.00) on this page — the trade-off being the extension cord tether. The 2-in-1 edger conversion (wheel flip) eliminates the cost of a separate edger tool, a genuine value add at this price. The auto-feed system's known weakness is over-feeding: it can release too much line at once, increasing breakage and waste. For buyers who prioritize consistent motor power for occasional thick-grass trimming without the cordless ecosystem cost, the BLACK+DECKER covers the core task at entry-level pricing.