Some of Stewart McInnes’s tulips are 29-year-old ones he planted when he first moved to the property. Here’s his advice for keeping bulbs producing for many years. Start with the soil—well-drained, acidic, with plenty of humus—then top it up with bone meal, which provides nutrients for both the roots and the flowers. Then select the right kinds. Darwin tulips will return for many years; species tulips will go to seed and generate new plants, as long as they’re not deadheaded. Fertilize when the leaves are dying back to provide food for next year. Other types are simply short-lived. He treats the more flamboyant, multi-headed, double early ones as annuals. Stewart plants a minimum of 2,000 bulbs each fall to keep up the population; he replaces most bulbs every three years or so.