Can you recommend a low-allergen tree?

Bay Laurel “Saratoga” species is non-invasive, and is a miniature cultivar of the California Bay Laurel. CityTrees has planted many of these specimens over the last 20 years, and they are hardy, drought tolerant, and generally good performers in our area. In addition, they are evergreen and this cultivar is only male. This means while it flowers, there is no fruit produced to clean up. The biogenic emissions (pollen) rating is low, so it is not considered a strong allergen, but I sympathize with your concern as allergy sufferers.

Other Resources: 

• Davey Trees recommends these species to minimize allergy reactions.
• If you have a particular species in mind you can look up its allergen information here at Selectree, an excellent database maintained by the Urban Forest Ecosystems Institute at Cal Poly.