Plant of the Month: Hazelnuts
Sometimes a native species looks just like a non-native. One example, blooming now in the Pacific Northwest, is the hazelnut or filbert.
Beaked Hazelnut male catkins with a tiny female flower at the upper right.
Corylus cornuta, beaked hazelnut, is our native species. On the west coast, it’s variety californica and in the rest of the continent you’ll find variety cornuta. It usually grows as a mid-sized multi-stemmed shrub but occasionally becomes a small tree.
Almost indistinguishable, Corylus avellana or European filbert, grows in the same habitats and except when it has nuts in late summer and early autumn you’ll be hard pressed to tell them apart. It’s grown commercially in Washington and Oregon for its very tasty nuts. In orchards this species is a medium-sized tree, but escaped to the wild it usually takes the same shrub form as our native hazelnut. There are also garden cultivars of Corylus avellana, particularly the very popular contorted filbet, var. contorta that’s been blooming for a while this winter.
Beaked Hazelnut in mid-summer.
Both the native and non-native species grow at the edge of woodlands where they get plenty of sunshine early in the year. They both have showy male catkins than dangle from the ends of branches. They both have a few diminutive red female flowers that hide along the twigs. They both have big, slightly fuzzy ovoid leaves all summer long. The only time you can positively tell them apart is when they have fruit.
Beaked Hazelnut fruit. Note how the husk completely encloses the nut.
On the introduced European hazelnut, the nut is clearly visible, although surrounded by hairy bracts. The nut of our native beaked hazelnut is completely enclosed by stiff, hairy bracts that form the beak that gives the species its common name.
Both our native Douglas’ squirrels and our non-native gray squirrels love hazelnuts. They seem to keep a keen eye out for them and know just when they’re ready to pick. That means that we humans have a hard time finding any nuts at all.
At this time of year, when the hazelnuts are about the first shrub to bloom, you might be able to tell the native from the non-native by a couple of clues. Botanical Electronic News reprints a table from the Native Plant Society of Oregon that is very helpful in figuring out the differences.
The clues I use most often this time of year are the number of catkins in a cluster, and the length of the catkin peduncle (the little stem between a flower and the twig). Our native species most often has catkins with 1 or 2 in a cluster on very short peduncles; the non-native usually have more than 2, on peduncles up to a centimeter long. The non-native starts blooming about a month before our native.
I’ve been seeing non-native Corylus blooming around Bellingham since January, as well as contorted filberts. Their catkins are now looking dingy brown instead of fresh and golden. The native hazelnuts should start blooming in our woodlands in another week or two. I think I’ve seen some catkins starting to expand, but I didn’t stop to look closely.
The important message to take way from all this is to be careful what you purchase for your garden at your favorite nursery. If you want to plant natives, which I think is a good thing, make sure you actually get the native species or variety. Pay attention to those details. Then compete with the squirrels for the nuts come autumn.