Elder, Sambucus nigra, is a native UK tree. They often grow near rabbit burrows as their foul tasting leaves are about the only thing rabbits won’t eat.
They are easily recognised in the summer by their flowers; clouds of white umbrels consisting of many tiny flowers. These flowers are edible and there are many recipes on this site here. The most common is elderflower cordial. As well as providing nectar for insects, the flowers are also eaten by dormice and voles.
Later in the year these will form berries. These are eaten by a variety of birds as well as mammals. Once again they can be consumed by humans, often in the form of elderberry wine. There is a recipe here.
There is a fair bit of folklore around the elder. Witches were said to have made their wands from its wood. And if the witch didn’t want to be a warty one, the cure for warts was to make as many notches in an elder twig as you had warts and then bury the twig. If you had been troubled by a witch, then a gift of elderflowers would break the spell. If you fall asleep under an elder tree, you might get to see fairies. The high levels of vitamin C in the berries meant that it was a useful tonic in herbal remedies, this might also explain why it is so closely associated with witches and their potions.