What is common mallow?

Easy common mallow identification starts with the leaves: round, softly hairy and scalloped, sitting on long stalks like a little geranium. It’s a broadleaf weed from Europe and Asia that grows as an annual or biennial, and in protected spots the crown can survive winter and regrow in spring.

Mallow does best where turf is thin and soil is hard-packed: driveway edges, sidewalk strips, play areas, barnyards and neglected garden corners. It isn’t aggressive in thick, healthy grass. When you see a lot of it, the lawn is usually telling you something about compaction or thin turf.

The nickname cheeseweed comes from the flat, round seed pods, which look like tiny wheels of cheese.

Common mallow identification: key features

Mallow usually grows low and sprawling, with stems spreading out from a single crown. In an unmowed spot it can stand about a foot tall.

• Leaves: alternate on the stem, nearly round to kidney-shaped with five to seven shallow lobes and toothed edges. The veins fan out from the point where the long leaf stalk attaches.
• Hairs: stems and leaves are covered in fine hairs. Seedlings start as a small round-leafed rosette.
• Flowers: five petals, white to pale pink or lilac, about half an inch across, tucked in at the leaf joints. They appear from spring into early fall.
• Seed pods: flat, round, segmented “buttons” that split into wedge-shaped seeds.
• Root: a tough, straight taproot with smaller side roots. It’s notoriously hard to pull by hand.

Where it grows in Pennsylvania

Common mallow is found throughout the state, especially around homes, farms and towns. It thrives in disturbed, compacted soil with plenty of sun, such as along curbs and walks, gravel driveway edges, garden paths, and in lawns that get mowed short and seldom fed.

In central PA clay soils that get driven or walked on, mallow and other compaction-tolerant weeds like prostrate knotweed and broadleaf plantain often show up together.

It’s also common in vegetable gardens and around compost piles, where rich, frequently turned soil keeps bringing seeds to the surface. Because seeds can sprout from spring right through late summer, you may pull one flush in May and find a fresh crop in August.

Common mallow look-alikes

The most common mix-up is with creeping Charlie, which also has round, scalloped leaves. Creeping Charlie has square stems, leaves in opposite pairs, a minty smell when crushed and purple-blue flowers. Mallow has round stems, alternate leaves, no strong smell and pale pink to white flowers.

Velvetleaf is a much bigger, upright relative with soft, heart-shaped leaves that can be several inches across. Wild violets have heart-shaped leaves growing straight from a ground-level clump instead of off trailing stems.

How to get rid of common mallow

Mallow is easiest to control young. Once that taproot is established it gets tough, and older plants shrug off herbicide more than you’d expect.

• Dig, don’t yank: use a dandelion fork or narrow trowel to lever out the taproot after a rain. If the root snaps off high, it can regrow.
• Hoe seedlings: in gardens, slice off young plants in spring before the root gets deep.
• Fix the turf: core-aerate compacted areas, mow at about 3 to 3.5 inches, fertilize on schedule and overseed thin spots in late summer or early fall. Dense grass leaves mallow little room to start.
• Mulch beds: 2 to 3 inches of mulch stops most seedlings in landscape beds.
• Lawn herbicides: Penn State notes that lawn broadleaf combinations containing 2,4-D, dicamba, MCPP or MCPA should give adequate control, and three-way products that include triclopyr, fluroxypyr or quinclorac also work. Spray young, actively growing plants in spring or early fall, and expect a repeat application on older plants.
• Beds and hardscape edges: glyphosate spot treatments work, but they kill any plant they touch, so keep them off desirable plants and turf.

Always read and follow the label (the label is the law), and make sure the product is labeled for your site: lawn, landscape bed or vegetable garden. In Pennsylvania, anyone applying herbicides for hire must hold a PA Department of Agriculture pesticide applicator certification, so larger lawn programs should go to a licensed lawn-care company.

Keeping it from coming back

Mallow seeds can sprout all season, so a single cleanup isn’t the end of it. Stay on new seedlings while they’re small and keep plants from setting their button-shaped seed pods.

Long term, address why it’s there. Loosen compacted soil, give foot or vehicle traffic a defined path, and keep turf thick. Along driveway and walkway edges, a clean border of mulch, edging or a well-built hardscape edge gives weeds far less bare ground to work with.

Questions we get about common mallow

Similar weeds

Creeping Charlie (Ground Ivy)Glechoma hederaceaProstrate KnotweedPolygonum aviculareBroadleaf PlantainPlantago major