Ranunculus bulbs are popular in Texas and other areas of the Southwest with mild winters. They grow best in USDA Zones 8 to 11. Plant ranunculus bulbs in October or November in Texas for blooms the following spring. There are several sizes of bulbs available. The jumbo bulbs will produce the most flowers per plant and they work well in containers. Smaller bulbs work best for mass plantings.
Choose the site where they will grow. Ranunculus like full sun and rich soil. A little shade in the afternoon is OK, but they should receive at least 8 hours of sun per day.
Prepare the garden bed. Loosen the soil with a garden fork or spade. Mix in a 3-cubic foot bale of peat moss for every 100 square feet of garden bed. (One bale of peat moss is enough for a flower bed that is 10 feet by 10 feet.) Add granulated all-purpose fertilizer in the amount recommended by the manufacturer. Rake the soil smooth.
Plant ranunculus bulbs. Note the bulbs have what look like "legs" dangling toward one side. Plant bulbs with these appendages facing downward. Dig a small hole for each bulb and plant them about 1 inch deep. Gently firm the soil over the bulbs with your hand. Space them at least 3 inches apart.
Cover the bed of ranunculus bulbs before winter with hay, straw or autumn leaves. This will insulate the ground and prevent it from freezing and thawing during winter, which could be fatal to the bulbs.
Remove the mulch in early spring, when temperatures rise above freezing during the day. Water enough to keep the soil moist until they start to germinate. Your fall-planted bulbs should bloom the following March. Once they are growing, they don't usually need additional watering, except in a severe drought.
Deadhead flowers to prolong blooming season. As each flower fades, cut it off with a pair of scissors. The plant will send up more flowers. Large ranunculus bulbs may produce as many as 35 blooms in a single season.
Stop watering the plants when the foliage turns yellow and fades. They will rest over the summer. Begin watering again in late summer and they will produce another round of flowers in late autumn.