Two‐ to three‐week‐old seedlings ofPicea abies, Pinus sylvestrisandPinus contortawere inoculated with the supervirulent strainAgrobacterium rhizogenesR1600 2cm above the base of the hypocotyl; other treatments included inoculation withAgrobacterium tumefaciensstrain A281 (pTVK291) or mock inoculation. Hairy or highly branched roots formed on 2–3% of seedlings of all 3 species that were infected by R1600 but on none of the other seedlings. Normal adventitious roots were also induced on 5–10% ofAgrobacterium‐treated seedlings but none appeared on the other seedlings. Opine assays and growth rates of hairy and normal roots indicated that only roots with the hairy morphology were transformed.