'Moonbeam' arrived in gardens as something of a revelation — a threadleaf coreopsis that bloomed in pale, creamy lemon rather than the species' more saturated gold. The effect is cooler, more luminous, easier to place beside silvers and blues and the warm pinks of midsummer. Growing one to three feet tall and wide with the same fine-textured, needle-like foliage as its parent, it produces sterile seeds, which means it will not self-sow but spreads quietly by rhizome to form ever-widening mats of airy green. Bees find it reliably attractive through a long season that stretches from summer well into fall.

Full sun suits it best, though it is forgiving of light shade in climates with intense summer heat. Poor, well-drained soil is an advantage rather than a hardship, keeping stems upright and encouraging the compact, mounded habit that makes it such a versatile garden plant. Rock gardens, sunny borders, mass plantings, and containers all work well. The one thing 'Moonbeam' genuinely dislikes is overwatering or heavy fertilization, both of which push it toward lax, floppy growth. Treat it lean and it will repay that restraint with months of quiet, flickering bloom.