The native bluebell (Hyacinthoides non-scripta) is an unmistakable sight in the British countryside where they are found in high densities, carpeting the ground with their blue flowers. Because they spread incredibly slowly, bluebells in great numbers are one of the key signifiers of nutrient-poor (particularly phosphorus) ancient woodland. The native bluebell is protected in the UK under the Wildlife and Countryside Act 1981, and there is some speculation that the charismatic species may be at risk of being outcompeted by the Spanish bluebell (Hyacinthoides hispanica) as it escapes from gardens and hybridises with the native bluebell.
Bluebells themselves are interesting as they spend most of their time underground as bulbs, emerging in Spring to flower for a couple of months and then disappearing again until next year. During Spring they manage to outcompete other plants found on the forest floor to create vast swathes of flowers. In forests with bluebells, bracken has been found to have its emergence and life cycle “pushed back” in areas where bluebells are densely populated.
Many plants use chemical warfare to maintain dominance on the forest floor, releasing chemicals that deter other plants. But bluebells don’t seem to use chemical strategies to ward off competitors. Instead, they succeed due to their ability to partner up with arbuscular mycorrhizae, a fungus which penetrates the roots of a plant and whose fungal network vastly increases the surface area of the plant's root network. Arbuscular mycorrhizal fungi make their living by uptaking phosphorus and exchanging it for sugars within the roots of the plant, without the fungi the bluebells wouldn’t get enough phosphorous to get by. This allows bluebells to accumulate phosphorus, and effectively starve out any competitors until they die back in Summer.