Poppy anemone does best in full to partial sun and a rich, organic soil that stays moist, but not wet. Before planting, soak the bulbs in room-temperature water for two to four hours to hydrate the root structure. Choose a spot with loose soil at least 15 inches deep. Mix in 2 to 4 inches of well-rotted compost to provide the plant with a source of slow-release nutrients. Plant the bulbs 2 to 3 inches deep, spacing them 4 to 6 inches apart.
Poppy anemone needs watering only while it is actively growing. Provide 1 inch of water each week when it does not rain. Keep the bulb dry when the foliage dies back to the ground. Do not water the poppy anemone when the plant is dormant, because excess water causes bulb rot.
Fertilize poppy anemone right after the flowers die. Apply 3 tablespoons of 5-10-10 slow-release fertilizer or bulb food, scattered throughout the clump. This provides enough nutrients to encourage root and bulb growth. Water the area well to dissolve the fertilizer.
Remove the poppy anemone's flowers when they die to neaten up the flower bed. Do not cut the leaves. Let them die back to the ground naturally. The leaves continue to photosynthesize, which feeds the bulb and helps with the development of next year’s blossoms. By the end of summer, the leaves turn yellow and wither away.
Over time, the poppy anemone produces new bulbs, which eventually become crowded, leading to fewer, smaller flowers. Dig the bulbs up every three to four years at the end of summer after the leaves wither. Separate the bulbs and store them in a cool, dry place until ready to replant them in fall.
Poppy anemone needs some winter protection in USDA zone 8 and lower. Cover the bulb bed with 6 to 12 inches of straw mulch in fall. This protects the bulbs from occasional freezing temperatures. Remove the mulch in late winter so the ground will warm up quickly in spring.