Portulaca oleracea thrives where most plants would not bother to try: compacted soil, drought, full sun, the verge of a cracked parking lot. Its prostrate stems are reddish and smooth, its leaves oval, fleshy, and alternate, clustered toward the joints in a way that speaks to efficient water storage. The small yellow flowers — barely a quarter inch across, with five heart-shaped petals — open briefly in the morning hours, replaced by seed capsules that split to release dark seeds in numbers enough to ensure the species never really leaves a garden once it has arrived. Sparrows eat the seeds; deer, pigs, and rabbits browse the leaves; sawfly larvae mine the foliage — this plant feeds a remarkable range of wildlife for something so easily overlooked.

In a kitchen garden context, purslane is worth a second look: the succulent leaves and stems are edible, with a mild, slightly lemony flavor, and have been eaten across cultures from the Middle East to Mexico for thousands of years. In an ornamental garden it functions best as an acknowledged self-seeder in dry, sunny margins where the gardener is relaxed about what fills the gaps. Crown rot can occur in poorly drained soil, and aphids may occasionally gather on soft new growth, but otherwise this is a plant that demands almost nothing in return for occupying difficult ground.