Pennywort is a low-growing, perennial aquatic weed that's known to invade over-irrigated, poorly drained landscapes and lawns. The robust stems spread horizontally, rooting in moist soil and forming thick, dense mats of rounded, coin-sized leaves.

Bright green, leathery pennywort leaves have scalloped margins. Prominent leaf veins share a central starting point. The sturdy leaf stems grow up to 6 inches tall and attach to the center of the leaf's underside.

Diminutive, star-shaped flowers appear in clusters on pennywort from late spring into fall. The white, five-petaled flowers grow on small stalks that emanate from a center point, forming domed, umbrella-like clusters of tiny blooms.


Pennywort is a common lawn weed through all but the most arid regions of the United States. Wherever marshy, wet conditions exist, pennywort is nearby — and ready to spread. The plant adapts easily to various soil types and conditions, surviving on land or floating on water.

Once established, pennywort tolerates shade and drier conditions. But this aquatic weed is most aggressive in moist areas with full sun. Poor drainage, excessive irrigation, overfertilizing and low mowing all favor pennywort's spread in lawns.


When treating pennywort or any lawn weed, always read product labels thoroughly and follow instructions. Some lawn grasses are sensitive to certain herbicides, so check labels before applying any product to your grass. Only treat established lawns, never newly seeded grass. Pennywort is most vulnerable to treatment when weeds are young and small.

Image Herbicide offers several highly effective products to kill or control pennywort:

  • Image Lawn Weed & Crabgrass Killer, available in Ready-to-Spray and Concentrate, kills even tough weeds like pennywort down to the roots. For best results, use this post-emergent weed killer when soil is moist and pennywort is actively growing.
  • Image All-in-One Lawn Weed Killer, available in Ready-to-Spray and Concentrate, starts working on contact to kill pennywort — roots and all. Use this selective, post-emergent herbicide as pennywort emerges throughout the growing season.
  • Image Southern Lawn Weed Killer for St. Augustinegrass and Centipedegrass, available in fast-acting Ready-to-Spray and Concentrate formulas, starts working immediately to kill pennywort and other tough listed broadleaf weeds in southern lawns.

Pennywort Control Tip: Pennywort thrives where overly wet soil causes lawn grasses to grow weak and thin. Correct poor drainage and monitor irrigation diligently to restore lawn health and eliminate pennywort's edge.

When you're looking for a granular option for post-emergent weed control, try Pennington UltraGreen Weed & Feed 30-0-4. It controls pennywort and feeds your lawn.

Always read product labels thoroughly and follow instructions, including guidelines for lawn grasses, frequency of applications and seasonal maximums that may apply.