I'd guess 'Moonbeam' to be one of the most frequently planted perennials for low water gardens, and for good cause. This little charmer has a delicate, thread-like leaf and airy countenance, and it blooms its little heart out all summer long, usually until frost. Blooms are small and pale yellow, somewhere between creamy and slightly greenish-yellow. Put it in perennial borders, parkstrips, along walks, in parkinglots. Grows about 12 to 18 inches tall and wide.
Grow in well-drained, slightly loamy to sandy-loam soils in full sun. Plants tolerate drier conditions than do the grandifloras. This coreopsis doesn't require deadheading to maintain bloom. however, during the peak of the summer heat, flowering may slow. shearing aback the plants a bit will encourage new foliage and usually another good bloom. Otherwise, it may bloom until frost, though the flowering will be less profuse. In optimum growing conditions, plants will spread in the garden over time by stolons to form an attractive ground cover, but spread is easy to check.