Ground Ivy, or Gill-Over-the-Ground, is the nemesis of every suburban homeowner who prizes purity in his lawn. For more tolerant types, it’s a friendly little plant. It never grows very tall; it has pretty blue flowers; and it makes your whole lawn smell minty when you mow it. This colony was growing in a lawn in Mount Lebanon, where it was blooming in late April.

Gray places this in the genus Nepeta:

NEPETA L. CAT MINT
Calyx tubular, often incurved. Corolla dilated in the throat; the upper lip erect, rather concave, notched or 2-cleft; the lower 3-cleft, the middle lobe largest, either 2-lobed or entire. —Perennial herbs. (The Latin name, thought to be derived from Nepete, an Etruscan city.)

N. hederacea (L.) Trevisan. (GROUND IVY, GILL-OVER-THE-GROUND.) Creeping and trailing; leaves petioled, round-kidney-shaped, crenate, green both sides; corolla thrice the length of the calyx, light blue. (Glecoma L.; Glechoma Benth.) Damp or shady places, near towns—May-July. (Nat. from Eu.)

Bugleweed is common at the edges of ponds, often dangling over the water. Here we see it framed by the clouds reflected in a pond in the Allegheny Cemetery in Lawrenceville.

Spearmint is especially common in urban yards and vacant lots, where it often escapes from cultivation. The prison isn’t built that can hold spearmint, which can be very invasive once you have it. But it’s such a useful herb that its sloppy manners are easy to forgive.

If it lived up to its name, it would be priceless. Heal-all grows at the edge of the woods, or in your lawn, or anywhere else it can find space. It’s a very common weed, but surprisingly beautiful close up. This specimen grew in Bird Park in Mount Lebanon.