Evergreen, understory shrubs, often members of the Ericaceae, have been implicated in the suppression of tree recruitment in many ecosystems. One possible mechanism of this suppression could be an allelopathic interaction between shrubs and seedlings. We tested the allelopathic potential of Kalmia latifolia L., an important component of southern Appalachian forest understories. Aqueous extracts of soil, humus, K. latifolia litter, mixed forest floor litter, and green leaves from K. latifolia did not inhibit germination or initial root elongation of our test species Lactuca sativa L. (lettuce). Root, shoot, and total biomass were reduced in P. rigida seedlings grown in forest floor substrate collected beneath K. latifolia compared to those grown in forest substrate without K. latifolia. While these differences were not significant, they could be exacerbated in the field when seedlings are exposed to multiple stressors (reduced light, water, and nutrient availability). Our findings suggest that allelopathy is not a strong mechanism in the inhibition of canopy tree recruitment by K. latifolia.