Theta Filbert Hazelnut

Theta is an Oregon State University hazelnut cultivar released specifically as a late-season pollenizer. It is intended to supply pollen to compatible hazelnut cultivars, rather than to serve as a primary crop variety. ## Pollination and disease OSU reports that Theta sheds pollen very late in the flowering season and is compatible with most cultivars; it is specifically suitable for ‘Jefferson.’ The OSU Extension compatibility tables distinguish compatible crosses and pollen timing, so select a partner from those tables rather than assuming any two hazelnuts will set nuts together. The breeder release describes complete resistance to eastern filbert blight from the ‘Gasaway’ source. Later OSU Extension reporting documents aggressive strains infecting some cultivars previously considered resistant, so monitor current regional guidance. [OSU’s Theta cultivar release](https://agsci.oregonstate.edu/eta-and-theta-hazelnut-pollenizers) · [OSU Extension hazelnut variety and compatibility tables](https://extension.oregonstate.edu/sites/default/files/documents/em9073.pdf) · [OSU Extension disease update](https://extension.oregonstate.edu/catalog/potential-new-aggressive-efb-strain-infecting-resistant-hazelnut-varieties) · [Burnt Ridge 2026 catalog](https://www.burntridgenursery.com/text/Catalog_2026.pdf) ## Maintenance Plant with compatible hazelnuts whose female bloom overlaps Theta’s late pollen shed. Maintain even moisture while young and keep the base accessible for inspection and seasonal care. In orchard settings, use local extension guidance for spacing, training, and disease scouting.