Guide
Ajuga: A Fast, Colorful Groundcover That Needs a Firm Edge
The short answer
Ajuga, or bugleweed (Ajuga reptans), is a low evergreen-to-semi-evergreen groundcover that spreads by runners into a dense mat of glossy, often bronze- or purple-tinted leaves, topped in spring with short spikes of blue flowers. It grows in everything from full sun to fairly deep shade and is a classic fix for cool, shady spots where grass will not grow.
Plant it on 6 to 12 inch centers for quick, thick cover in moist, well-drained soil. The main management issue is its speed: it is listed as invasive in parts of the country, and its runners readily escape into lawns and perennial beds, so give it a hard edge and check it periodically.
Where It Works
- Tolerates all light levels, from full sun to shade; foliage color is often richest with some sun.
- Excellent for moist, shady areas where turf fails; tolerates moderately dry soil once established (Clemson HGIC).
- Avoid wet, heavy soils and cramped, stagnant corners — good air circulation reduces disease.
- Do not plant directly beside lawns or perennial borders unless you are willing to edge out runners regularly.
How to Plant It
- 1Space on 6 to 12 inch centers — Close spacing gives a thick, weed-smothering mat within a season or two (Clemson HGIC).
- 2Set crowns at soil level — Plant rosettes with the crown at grade in moist, well-drained soil and water in well.
- 3Mulch lightly between plants — A thin mulch keeps weeds down while runners fill the gaps.
Care and Containment
Ajuga needs little routine care; some gardeners mow or shear off spent flower spikes to keep the mat tidy. Divide crowded patches every few years to keep them vigorous and well-aerated.
Containment is the real job. The plant spreads quickly by above-ground runners, and University of Maine Extension notes it is listed as invasive in parts of the country. Periodically edge out runners at the borders of its assigned area so it does not creep into turf, where it is hard to remove.
⚠ Ajuga escapes into lawns easily and is considered invasive in some regions. Keep it edged, and check your state's invasive plant list before planting large areas.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Clemson Extension HGIC — Ajuga — Planting on 6-12 inch centers for quick establishment, tolerance of a range of light and moisture, avoiding wet heavy soils, use where grass will not grow
- North Carolina Extension Gardener Plant Toolbox — Ajuga reptans — Spread by runners into a dense mat, listed as invasive in other parts of the country, advice to avoid planting near beds and lawns where removal is difficult
- University of Maine Cooperative Extension — Can I use Bugleweed in place of Fescue grass lawn? Is it invasive? — Need to edge out vegetative runners so ajuga does not escape its assigned area; invasive listings elsewhere