Ranunculus produces peony-like flowers throughout the spring months. It grows hardy in USDA planting zones 8 through 11, but it cannot tolerate the winter frost in zones 3 through 7. Plant ranunculus in fall in mild climates and in early spring if your area experiences frost. With only minimal care you will quickly have a bed full of colourful blooms.
Site and Soil
Ranunculus can't grow in wet soils, as their tuberous root systems rot when exposed to too much moisture. Plant the tubers in a well-drained garden bed that receives full sunlight. Work peat or compost into the bed before you plant to help improve drainage. If you leave ranunculus in the bed year-round, ensure the location isn't prone to collecting standing water from snow melt or rainfall in winter.
These flowers require only minimal watering, getting most of the moisture they need from rain. Ranunculus can't survive standing water, but it grows best in soils that remain slightly moist. Water the tubers thoroughly after planting, moistening the top 6 inches of soil in the garden bed. Spread a mulch over the bed after planting to help keep the moisture in the soil. Resume watering once the tubers send up their first sprouts, but only water when the soil begins to dry.
Minimal fertilisation is required for ranunculus to grow successfully. If you dig up the roots each year, the only fertilisation required is the addition of compost to the soil before you replant. Perennial ranunculus beds benefit from yearly applications of a balanced fertiliser at the recommended rate once new growth begins in spring. If your soil contains plenty of organic matter, the plants flower dependably even without fertilisation.
Cover the bed with a fresh layer of mulch after the first fall freeze if your climate and soil conditions allows you to grow ranunculus as perennials. In colder areas, or if your beds become too moist in summer or winter, dig up the roots after the flowers and foliage wilts in early summer. Dry the roots, then store them in a cool basement until you are ready to replant in fall or spring.