October 27, 2018
Part of your confusion may be from the word Ranunculus which refers to a large group (genus) of flowering plants. Some are bulbs (tubers, really) and some, like creeping buttercup, multiply rapidly from stolons. I think you are asking about the tuberous ranunculus, Ranunculus asiaticus aka Persian buttercup. They are winter hardy only in zones 8-10. You can bring them inside over winter like dahlia or glads then plant in spring. Because they must have moist and cool soil, they only bloom in spring. The tuber will get larger each year and the larger the tuber, the more flowers it produces. You can divide the tuber to increase the number of plants. However, Ranunculus tubers are inexpensive to buy and most northern gardeners grow them as annuals.
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