Violet flowers are part of the genus Viola and consist of 500 different species including annuals, perennials, biennials and subshrubs. They have a distinct five-petaled flowerhead that grows in a wide range of colors and shapes. Violets prefer full sun to part shade and nutrient-laden soils that are fertile and moist. They also require a regular amount of deadheading or removing the spent blooms to promote a long flowering season. Tucked into containers and flower borders they create a showy garden display.
Sweet White Violet
Sweet white violet (Viola blanda) is a perennial violet variety that emerges in spring to last into early summer. Growing 6 to 12 inches tall, sweet white violets have white blooms with purple vines running on the lower petals. The upper petals bend backwards and twist. The stalk on sweet white flowers is green with a red tinge. The heart-shaped foliage grows 1 to 2 inches wide with a smattering of hairs. Sweet white violet flowers require a shaded planting site that is moist to wet. They also grow best in acidic soil. Plant sweet white violets in U.S. Department of Agriculture (USDA) hardiness zones 3a to 9a.
Common Blue Violet
Common blue violet (Viola sororia) is a perennial flower that grows 3 to 8 inches tall. The blue to white five-petaled flowers grow ½ to ¾ inch wide with white to purple veins. Attached to common blue violets are the smooth green stalks that hold up the blooms. Common blue violets emerge in spring to last into early summer. The foliage is heart-shaped and grows up to 5 inches wide. Common blue violets are found growing in damp woods and moist meadows. They grow best in well-drained, moist soils. Plant in USDA hardiness zones 3 to 6.
Bird's Foot Violet
Bird's foot violet (Viola pedata var. lineariloba), a variety of violet flower, is a perennial flower that grows 6 to 12 inches tall. Emerging in spring to last into summer, bird's foot violets have pale lavender to deep violet blooms, with an occasional white bloom. The lower petal on bird's foot violets is always wider than the remaining four and the center contains the orange anthers. The green foliage is made up of finger-like segments that are deeply divided in shape. Bird's foot violets are found growing on sandy and dry roadsides, as well as along the edge of woodlands. Plant in USDA hardiness zones 2 to 9.
According to Fine Gardening magazine, "This annual, biennial or short-lived perennial is grown for its long season of pansy flowers in shades of purple, blue, yellow and white. Growing less than 6 inches tall and wide, wild pansies (Viola tricolor) have a moderate growth rate and heart-shaped leaves. They emerge in spring to last into fall, making for a long blooming season. Wild pansies grow best in full sun to part shade and nutrient-laden soil that is well drained. Plant in USDA hardiness zones 3 to 9.