Hazelnut: One Tough Shrub

Wouldn’t it be great if there was a shrub that could tolerate both sun and shade, acidic or alkaline soils, and the driest of sites? That shrub exists in our native Filbert, otherwise known as Hazelnut (Corylus americana.) So why isn’t it being planted more often and used by landscapers? Hazelnuts belong to a group of plants that I refer to as the foot soldiers in the landscape. They don’t have a flowering characteristic that catches the gardener’s eye, but perform well in all seasons of the year. The common name filbert evolved from European folklore that connected it with Saint Philbert’s day, August 22, the date that traditionally was the start of the filbert harvest in Europe.

American filbert is native to the northeastern corner of the United States, including most of Wisconsin with the exception of the area bordering the upper peninsula of Michigan. In more northern areas, this species is replaced by its close relative, the beaked hazelnut, Corylus cornuta. It is a multistemmed shrub that usually matures at 6 to 12 feet. Filbert is in the birch family, which means that it produces long drooping pencil-like catkins shortly after temperatures are consistently above 40 degrees. Though not exceptionally colorful, they do provide interest in the landscape at a time when nothing is yet in bloom. If grown in full sun, the fall color of the soft, dark green leaves can be an exceptional yellow, orange, or red. The fruit is an edible oval nut that is enclosed by 2 leaf-like bracts, which often hide it from the undiscerning eye, but do nothing to protect it from squirrels. While only about 1/3 the size of the commercially grown filberts, which are derived from its European counterpart, Corylus avellana, its taste is just as good.

In Wisconsin, American Filbert is found in upland dry to moist wooded areas, open hillsides, fence rows, and even rocky wastelands. It will tolerate dry sandy soils, but is intolerant of floods and wetlands. Insect and disease problems are rare. Hazelnut has a long history of being harvested for food by Native Americans. The nuts, which are high in vitamin E, can be eaten raw, roasted, or ground into a paste. Hazelnut has also been used medicinally by Native Americans. The Cherokee are reported to have used a tea made from the inner bark in the treatment of hives and fevers. A decoction of raw nuts was employed to control bleeding during childbirth, and one made from the roots was used to sooth teething babies.

Hybrid varieties have been developed from Corylus americana, Corylus cornuta, and Corylus avellana, but they are not readily available to the homeowner. The only cultivar of American filbert that I am familiar with is called ‘Purple Haze.’ It has brilliant purple leaves in the spring that gradually turn green throughout the summer. It was developed and released by McKay Nursery in Waterloo, WI and, to my knowledge, is only available through them. As a testament to its toughness, I dug out a piece of ‘Purple Haze’ that I was growing at my home in Peoria, IL when I moved to WI in 2011 and it has developed into a nicely formed, multistemmed shrub. I recently added a second to my Cedarburg yard that I obtained from McKay’s.

Several years ago I transplanted a bare root plant of American filbert from a sandy location near Wautoma to my home in Cedarburg. Though near death, it survived the difficult move and is maturing nicely. It will be interesting to see if growing on my loamy soil will allow it to exceed the three foot mature height it attained on its former site. This tough, adaptable plant is definitely underutilized. Seek it out and give it a try.