I've tried different reticulata varieties from big box stores, but they never persist in my garden. Any ideas why they fizzle out instead of steadily increase like most spring bulbs? Do they have different cultural requirements than Muscari, daffodils, tulips, etc.? Because that's what I've tried to grow them alongside. I'm wondering if they need a raised bed with fast draining soil. It surely can't be winter cold killing them off. I'm in SW Ohio (USDA Zone 6). Thanks, Dennis in Cincinnati