Buckthorns are modest trees with with great ecological values. They are not often planted in our gardens as they bear tiny flowers but they are important trees for wildlife.
The flowers of Alder buckthorns are small, inconspicuous and greenish white in colour. I can imagine this description does not make you ecstatic right away but bear with me for a few more minutes because this modest tree has a lot to offer.
It usually grows to about 5 metres at most so it will suit the smaller gardens as well. It flowers from May until September, sometimes even until October which makes it a very valuable plant for pollinators. It grows best on acidic soils but my experience is that they are easy to grow. Many beekeepers love this plant as it offers both pollen and nectar during a long period of time. There is a mining bee, Andrena fulvida that depends on this tree. Bumblebees and butterflies often visit this tree and in woodland, where this tree can be found, it is often one of the few plants that provide nectar. In my garden, many Early bumblebees, Tree bumblebees, honeybees and buff-tailed bumblebees feed on this plant.
Another reason why you could consider planting this tree is that it is the only food plant for the Brimstone butterfly, together with purging buckthorns. If you live in the right area, you may get lucky and some Brimstones might visit your garden and stay there.