Answer: Wow! You must be treating them well if they're six feet tall! There are nearly 250 species in the Ranunculus group and the most commonly grown is R. asiaticus, the Turban Ranunculus. These perennials grow happily in full sunshine in average garden soil with regular watering in the spring and summer. They are generally started from tubers, not from seed (because it takes so long for them to bloom and grow from seed).
In your climate, you can leave Ranunculus in the ground all year round. (In colder climates the tubers should be dug after the foliage dies down, and stored for replanting the following spring.) When the plants stop blooming you can stop watering. After the foliage yellows and dies, cut it back to ground level. Next spring your Ranunculus will sprout again. After a few years you can dig and divide the clumps of tubers.
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