Bird cherry tree (Prunus padus): how to identify it

Webs of bird-cherry ermine caterpillars

A bird cherry covered in grey silk, with the leaves stripped, is the most common reason people search for this tree. Butterfly Conservation names the bird-cherry ermine moth, Yponomeuta evonymella, whose caterpillars feed together in a web on bird cherry and are sometimes a pest of it; it says the web can cover whole trees. The adults fly at night from June to September.

Forest Research lists small ermine moths among the native species that may be mistaken for oak processionary moth. It describes webbing that trails over the whole plant in spring and early summer, says that even in extreme cases the caterpillars should not affect the long-term health and vigour of the plants, and notes that infestation rarely hits the same tree year after year. Small ermine caterpillars are hairless, cream or white with black markings, and are not known to feed on oak; oak processionary moth feeds only on oak and builds rounded nests on trunks and large branches.

If the nest is on an oak, or you are unsure what the tree is, do not touch it; in the UK, Forest Research's Tree Alert is the place to report a suspected oak processionary nest. Tree Identifier's Diagnose tool can give a quick first opinion from a photo of the webbed branches, but it is not a lab diagnosis.

Bird cherry vs wild cherry, black cherry, chokecherry and rowan

Wild cherry. The Woodland Trust names wild cherry, sour cherry and cherry plum as the trees to rule out, and gives two tests: bird cherry's flower clusters hang, and bird cherry does not send up suckers from the roots as wild cherry does. The cherry page covers the true cherries.

Black cherry. The American black cherry, Prunus serotina, has the same hanging spikes. NC State's black cherry profile gives a forest tree of 60 to 80 feet with narrow leaves 3 to 6 inches long with fine incurved teeth and yellow-brown hairs underneath, flower spikes 3 to 6 inches long from late April to May, purple-black cherries about 3/8 inch, and mature bark that turns dark and scaly. Scaly plated bark on a big trunk points to black cherry.

Chokecherry. In North America, the native look-alike is chokecherry. NC State's chokecherry profile describes a shrub or small tree of 20 to 30 feet with serrate leaves, white flowers in spikes, red fruit turning black, and dense thickets from long underground runners. The two are hard to separate on looks alone, so location matters: bird cherry is native to Europe and northern Asia and planted in North America. The chokecherry page gives its field tests.

Rowan. By northern streams in spring, rowan also flowers creamy white. The Woodland Trust rowan profile describes pinnate leaves of 5 to 8 pairs of toothed leaflets plus one at the tip, flowers in dense clusters and scarlet berries in autumn. One look at the leaf separates it; see the rowan page.

Other dark-fruited trees are sorted in trees with black berries.

Where bird cherry grows: Britain, Europe and Alaska

The Woodland Trust lists bird cherry as native to the UK, with a native range across northern Europe and northern Asia. In Britain it is common in northern England, Wales and parts of East Anglia, and rarer in the south, especially the southwest; it favours wet woodland, hedgerows and the banks of streams and rivers. NatureSpot calls it scarce in Leicestershire and Rutland and probably not native there, apart possibly from Grace Dieu Wood.

The Woodland Trust says the foliage is toxic to livestock, particularly goats. In Alaska, where bird cherry was planted in yards and parks, the state's Division of Agriculture describes it as rapidly invading stream sides and natural forests in Anchorage and Fairbanks, recorded as far north as the south side of the Brooks Range. It notes that the tree produces cyanogenic glycosides and that, in rare cases, it has caused cyanide poisoning in moose. There it flowers from late May to early June and can form dense thickets up to 30 feet tall.

If a child or pet may have eaten leaves, seeds or fruit, call NHS 111 (or your local poison control service) or a vet. For the native trees around it, see the guide to UK native trees; Tree Identifier's Tree Map can save each located bird cherry so you can check its fruit later in the summer.