Bluebells have got issues. There are two kinds of bluebell growing in the garden: tall, upright, unscented ones related to the Spanish Blubell (Hyacinthoides hispanica) and smaller, drooping, fragrant ones which are sometimes called English Bluebells (Hyacinthoides non scripta). I think these are the lovelier of the two.
 The former were here when I moved in, the latter planted by me. Spanish Bluebells have been grown in this country for centuries and became a mainstay of the bulb trade. H. hispanica is easier to establish and thrives in a wide variety of conditions whereas H. non scripta is harder to naturalise. In particular it doesn't like to dry out either in the soil or when lifted so it doesn't store or travel well as an item to be sold by the bulb trade.
 In ancient bluebell woods H. non scripta is the native species. Like many quintessentially English things it's also Welsh, Scottish, Irish and North European. The issue is that where it cross pollinates with the Spanish Bluebell the genetic characteristics of hispanica dominate. The hybrid Hyacinthoides x massartiana  looks more like hispanica and supersedes non scripta as the dominant type. This is not yet the case in ancient woods remote from human habitation but in theory it's inevitable and already a done deal in towns, cities and much of the countryside where bluebells are in effect a "hybrid swarm" of mixed genes.
 The Spanish Bluebell means no harm, it's just doing what comes natural. Indeed in the wild the southernmost range of non scripta and the northernmost range of hispanica must overlap so is hybridisation happening there of its own accord anyway? Hyacinthoides is perhaps then a very variable species by nature.
 Here we enter the science of genetics about which I know very little but it raises some interesting questions. I suppose we humans are a "hybrid swarm"!
 Some ecologists are on a mission to pull up hispanica and the hybrids but they have merit as garden plants in their own right. Trying to eradicate them now is probably a case of locking the stable door after the horse has bolted though I wouldn't want to plant them next to an ancient bluebell wood.
 I bought bluebells of the drooping, fragrant variety from a specialist grower based in Wales. They're dispatched freshly lifted, arrive still moist then planted straight away. I've tried them in different spots with mixed results; growing them in the grass beneath the shade of the apple tree seems to be to their liking.