Tree seedlings inoculated with ectomycorrhizal fungi have been found to improve survival and growth in ecologically inhospitable sites. We tested if Kalmia induced allelopathic growth inhibition in black spruce can be overcome by ecomycorrhizal inoculation of black spruce seedlings. Our laboratory and greenhouse experiments showed that out of 51 ecotmycorrhizae four, Paxilus involutus, Laccarialaccata, xx and E-strain were not only able to tolerate the toxicity of Kalmia leachate but had better root and shoot growth in the presence of Kalmia leachate as well as living Kalmia compared to the control. In laboratory experiments we found that Paxilus involutus was able to degrade Kalmia phenolic compounds and use them as their carbon source to stimulate growth of mycelial biomass and colony diameter. However, when the black spruce seedlings pre-inoculated with P. involutus were out plants in Kalmia sites they did not show significant growth enhancement compared to the uninoculated control seedlings. Functional differences in different stains of ectomycorrhizae and rhizosphere ecology of Kalmia under field condition will be discussed.