While indoor flowering plants come in a wide range of colors and forms, those with blue flowers are less common. However, blue flowering plants appear in abundance at florist shops in the spring, when they're especially popular as Easter and Mother's Day gifts. With proper care, some of these plants will continue to provide soothing blue flowers through the year, or successfully transition to the garden
Among the most popular of indoor plants, African violets (Saintpaulia ionanthia) are native to South Africa. These small, heavily blooming potted plants will perform for years in the right locations. They're available in dozens of cultivars with different bloom and leaf types and colors. The first 10 commercial culitvars, including Blue Boy, Amethyst, Admiral and Neptune, were blue. Frilled blooms and leaves, double flowers and pink violets all came from mutations in these plants.
Plants require temperatures between 60 and 80 degrees Fahrenheit, with nights 10 degrees lower than days. Provide bright locations with no direct sun except in midwinter. Let the soil dry between watering. If your home's air is dry, provide humidity by placing the pots in saucers of water.
Cineraria (Pericallis cruenta) is a flowering indoor potted plant popular at Easter and Mother's Day. Standing 1 foot high and wide, cineraria has daisy-like flowers in dark blue, deep pink, red, purple and several pastel shades. White-centered varieties are especially striking. A garden perennial in USDA hardiness zones 9 to 11 with a minimum annual temperature of 20 degrees F, it's a summer annual elsewhere. Potted indoor cineraria requires a cool, humid location in bright, filtered light and rich, well-drained soil. Ideal temperatures are between 55 and 65 degrees Fahrenheit during the day and 45 to 50 degrees Fahrenheit at night. Excessive watering causes root rot and diminished blooms. When watering, do not wet the leaves. Discard plants after blooming.
More Easter and Mother's Day best-sellers, potted hydrangeas (Hydrangea macrophylla) are green-leaved shrubs with showy globes or flat clusters of white, pink, blue or variegated blooms. They like bright light, evenly moist soil and nighttime temperatures between 50 and 60 degrees Fahrenheit. When flowers have faded and danger of frost has passed, plant hydrangea in a sheltered garden spot. To maintain your plant's blue flowers, test the soil. If it's not acidic (below 7.0 pH), acidify it with peat and aluminum sulfate. Doing this indefinitely, however, may alter your soil so much that the plant can't get nutrients.