Tough yet pretty, shasta daisies (Leucanthemum x superbum) kind mounds of large daisy flowers and work nicely with companion plants that contrast their shape and colour. Ideal companions also adore the same warm, dry growing conditions. Spreading 2 feet wide and two to three feet tall, shasta daisies are hardy at U.S. Department of Agriculture plant hardiness zones 4 to 10. They flower during summer, so choose plants that provide a succession of complimentary blooms.
Winter Iris
Winter irises (Iris), using their long, refined stems and wide-petalled purple flowers, give a gorgeous contrast to the white and yellow-bloomed, curved shasta daisy shape. Hardy in USDA zones 3 through 9, winter irises grow about 2 feet tall and carry late spring flowers to the tips of long-leaved stalks. Planted behind and slightly to the side of shasta daisies, winter iris flowers peep through newly-emerging daisy flowers, and their leaves provide a green background through the rest of summer. They enjoy full sun and moderate water.
Germander Sage
Sages adore a warm, dry place in garden boundaries, and germander sage (Salvia chamaedryoides) complements shasta daisies nicely. Its fairly, sky-blue, summer flowers and subtly beautiful, sage green leaf highlight shiny, green shasta daisy leaves and yellow and white flowers. Growing only 12 inches tall, the plant is best positioned toward the front of your daisies. Germander sage is low maintenance, hardy in USDA zones 7 to 11, and has the added benefit of being very attractive to hummingbirds and butterflies.
Ruby Grass
Grasses are infrequently the house gardener’s first selection for flower borders, yet most are simple to care for and many are quite pretty in bloom. Ruby grass (Melinus nerviglumis) echoes the shasta daisy mound shape but intercede its coloring with gorgeous, fluffy, amethyst pink blooms. Flowering throughout summertime, the 8- to 12-inch-long flowers turn root beer red as they mature. Ruby grass grows 1 to 3 feet tall, with a comparable spread, and is hardy in USDA zones 8 to 11. It enjoys warm, dry conditions.
Care
Care of shasta daisies and their companions, winter iris, germander sage and ruby grass, includes summer watering only when rainfall is less than an inch a week. Fertilizer needs can also be minimum: a thin layer of compost in spring is sufficient. To help control weeds and retain moisture, then spread a 2-inch layer of shredded bark or leaf mulch in spring. When daisy and winter iris clumps grow too big, which is usually every three or four decades, dig them up and split into sections before replanting. Staking excessively tall daisies and mud iris helps to keep them upright.