Ranunculuses, or Persian buttercups, are perennial bulb flowers that grow best in USDA zones 8 through 11, meaning they are frost tender and cannot survive winter temperatures below 10 to 15 degrees F. Dig up and store the bulbs during the winter if you don't live in a climate that has warmer winters. Ranunculuses bloom for only about one or two months between July and August, but their flowers are rather showy, blooming in shades of pink, red, orange, yellow and white.
Plant the ranunculus bulbs 1 to 2 inches deep, spaced about 3 to 3-½ inches apart in well-draining soil. Plant the flower bulbs in a location that receives full sunlight in borders or flower beds.
Feed the ranunculus bulbs a flower-bulb fertilizer at the time of planting. Follow the directions on the package for dosage.
Water the bulbs thoroughly every day for the first week after planting. Soak the bulb and soil generously.
Feed the ranunculus plants when they begin to flower and again when their blooms have faded with a bulb-flower fertilizer as directed on the label.
Water the Persian buttercups once or twice each week to soak the soil down to the bulbs. Water more frequently during hot, dry spells or droughts, and anytime the soil feels dry to the touch.
Cut back the flowering stems after the blooms have died off. Allow the main plant to die back to the ground without cutting it. This usually takes about two to three months after the blooms die.
Dig up the bulbs in the fall and store them during the winter in a dry, cool place. Don't be surprised to see as many as eight new tubers from a single bulb each year.