Coreopsis

kor ee OP sis: I love SOME of these. Coreopsis have several different species, some are definately more hardy than others. The flowers have a 'composite' type flower, often referred to as 'daisy type.' Many types have 'cut' looking edges on their petals, these are 'lancelota' types. Nearly all older terms describing plants & plant parts are in Greek. But often we can easily recognize similarities in words. 'Lancelota,' to us means lance or lancing = cut edge.

Above is Coreopsis 'Cutting Gold.' I grow this super hardy type from seed. I plant them in late winter, and by late summer they will fill a 2 gallon pot in one season. That is very good growth for a perennial. I field grow these plants as well as their thick stems make a beautiful addition to our bouquets. Flowers on this plant are 2-3" across. Cutting Gold has a main bloom period in early summer, cut back it will have a smaller re-flush. This type is 24-36" tall, so good for back of border.
Threadleaf types seem to be 'unhardy' for our zone (4). At least that has been my experience. On the threadleaf types, their foliage is very 'threadlike' skinny and the plant looks (to me) like a caterpillar ate the foliage off. I prefer full, lush plants, so even on their best day, I wouldn't be a fan of this type. Coreopsis mostly come in yellows, golds & oranges. There are also some whites, pinks & bi colors.

Plant info: Full sun, regular water needs, no insect or disease issues.