Daisies have the distinction of being dicotyledonous, which means that each seed has two embryos and spawns two flowers in one bloom. The outside of a daisy has the long strap-like petals called the ray florets. The inner sphere, which is sunny yellow in many cultivars, is actually another flower composed of a group of tiny tubular petals, the disc florets.
Of the hundreds of species of daisies, the three most commonly grown are the Ox-Eye Daisy, the Shasta Daisy, and the Gerbera Daisy.
Both the Ox-Eye and the Shasta Daisy are hardy perennials in the genus Leucanthemum, which is from the Greek words leukos (white) and anthemon (flower).
Ox-Eye Daisy (Leucanthemum vulgare and also Chrysanthemum leucanthemum) is a creeping perennial with fairly shallow roots. The Ox-Eye Daisy is a wildflower that can be found worldwide, but because of its invasive nature, sale of the Ox-Eye Daisy is forbidden in several US states as well as in Canada.
Although at first glance the Ox-Eye Daisy is similar to the Shasta Daisy, it has several singular traits that make it easily distinguishable. The Ox-Eye Daisy grows in corymbs, which means that flower stalks branch out from the main stem, while the Shasta Daisy is a terminal bloom (flowers at the end of an individual flower stalk). Shasta Daisies are more robust in both flower and foliage than Ox-Eye Daisies are.
Both the Shasta Daisy (Chrysanthemum maximum or Leucanthemum superbum) and the Ox-Eye grow in clumps, as do most perennial daisies, and can be propagated from division of rhizomes. In fact, regular division of your daisies (every two to three years) keeps blooms larger and old growth from crowding out new growth.
Although most daisies are perennials, a few species, like the Gerbera Daisy (aka African Daisy) are annuals. The Gerbera Daisy (Dimorphotheca aurantiaca) heralds from Madagascar and was originally imported especially to grace floral bouquets with its colorful essence. Although the African Daisy is of a different genus than the Shasta Daisy and the Ox-Eye, it is still very much a member of the daisy family!
Daisies tolerate less than perfect soil and partial shade, but they are at their best in well-drained and nutrient-rich organic soil when grown in full sun. All daisies, whether annual or perennial, can be started from seed. In fact, most species of daisy are generous self-seeders if given the chance. To let daisies self-seed, just don't deadhead them. When the disc florets are dry, the daisy is ready to drop its seeds.
To add daisies to your garden by sowing seed, wait until all danger of frost has passed. Seeds are tiny and the easiest way is to broadcast the seed since it needs to be covered only by 1/16 inch of soil. Germination is slow in many cultivars, taking from two to four weeks, so patience in growing daisies from seed is a virtue!