Ask Mr. Smarty Plants

The Lady Bird Johnson Wildflower Center Native Plant Database has good information about this valuable native shrub. American hazelnut (Corylus americana) is a dense, mound-shaped, thicket-forming shrub, 6-12 ft. tall. Yellowish-brown catkins are showy in late winter and early spring. The female bloom is small and obscure, looking like red filaments. The male flowers are the long catkins. Edible nut with ragged papery husk. Fall color varies from bright yellow to deep wine-red.

Plants for a Future writes that the hazelnut flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by the wind. The plant is self-fertile.

Hazelnut is one of the first things to flower in the early spring, says Restoring the Landscape on their website. In early to mid April before the leaves have emerged, the male flowers (catkins) start to elongate on the stem and turn a bright yellow as the pollen matures.

You have to look a little more closely for the female flower which is also attached to the woody stem in a scale like bud. The stigma and styles are a bright red and start to protrude to catch the wind borne pollen from the end of the scaled bud.

And the Friends of the Wildflower Garden website says that the plant is monoecious (separate male and female flowers). The male flowers are very conspicuous light brown catkins, 2 to 5 inches long, appearing in a cluster of 2 or 3 on the sides of small branches near the branch tips opening before the leaves appear. These appear on the branches in the fall but open in the spring. The male flowers on the catkin have 4 stamens surrounded by two small bracts. The female flowers are quite small, with several rising from what appears to be a bud near the end of a twig in early spring. Only the stigma and styles protrude, looking like thin red threads. After pollination by the wind, the male flowers wither away and the pollinated female flowers mature to a 1/2 inch diameter edible brown nut that is enclosed in a leaf-like hairy bract that has ragged edges. This is green initially, becoming brown at maturity. Nuts will usually be in a cluster of 2 to 5.

Your hazelnut should produce fruit without cross-pollination and at an early age (3-4 years), but if you find that the quantity of fruit is not sufficient, you should get a better fruit set if there is another Corylus (it doesn’t have to be the same species just as long as it is blooming at the same time) in the vicinity.