Beautiful miniature landscapes can be created in window boxes with a variety of plants. Flowers provide a spot of warmth, color and beauty to window boxes. There are a number of flowers that do well in window box gardens. Choose flowers based upon your aesthetic preferences, space requirements, gardening habits and the location of your window box.
Marigolds (Tagetes spp.) are native to South and Central America. Bright yellow, orange or striped red flowers against lacey leaves grow to heights of 6 inches to 4 feet, smaller varieties are perfect additions to window boxes. Considered annual herbs, according to the West Virginia University Extension Service, marigolds grow rapidly in full sun. They prefer moist, but not wet, soil at all times. This can be achieved with a plastic window box planter, according to "Window Boxes: Indoors and Out," but is hard to maintain with wooden or terracotta planters. Alternately, an automatic or glass watering bulb may be placed near marigolds to keep their soil sufficiently moistened throughout the day.
Marigolds possess a particular pungent odor that some say resembles cat urine. This odor wards off pests. Deadhead spent blooms to encourage flowers all season. Marigolds are tolerant of neglect and cold, making them a good choice for window box gardeners who frequently forget to care for their space.
Nasturtiums (Tropaeolum minor) are a "versatile plant," according to the Vermont University Extension Office. Nasturitums grow equally as well in the window boxes as they do in the ground. There are dwarf nasturtiums, which are small and bushy. Trailing types cascade out of window boxes toward the ground, while climbing types attach themselves to window ledges and houses. Growing best in full sun, most nasturtiums tolerate partial shade. Preferring light, sandy soil, nasturtiums need a square foot of space or less to thrive. Blossom colors are white, yellow, orange, red and everything in between. Nasturtiums grow rapidly and prefer moderately damp soil. Window boxes dry out quickly, so an automatic or glass watering bulb may be in order for nasturtiums to grow well in the notoriously dry window box setting. They tolerate a fair amount of neglect and do not transplant well. These flowers bloom from early spring to fall.
Pansies (Violax wittrockiana) are delicate in appearance. Appearances can be deceiving, as these plants are extremely cold hardy. Pansies prefer full sun, according to the University of West Virginia Extension Office. They tolerate all soil types, but prefer rich, well drained soil with loam. Water pansies in the morning to prevent scorching, and apply about 1 inch of water per week to their window box. Fast growing flowers, pansies are available in nearly every color imaginable with abundant striped and variegated varieties. Flowers bloom in spring and fall.
Miniature roses, Rosa chinensis 'Minima', thrive in container conditions, according to the Iowa State University Extension Office. Found in every color except blue and available in sizes ranging from 3 to 18 inches tall, miniature roses prefer full sun in all but the hottest parts of the day.
Water miniature roses when the soil is dried to the touch, and water thoroughly until the soil is soaked. Avoid splashing the leaves to prevent scorching. Fertilize miniature roses regularly for abundant blooming, and prune off spent or finished blossoms. Miniature roses should be covered in winter, or brought indoors, to ensure they bloom again in the spring.