Response of four ornamental shrubs to container substrate amended with two sources of raw paper mill sludge

Four deciduous ornamental shrubs {'Coral Beauty' cotoneaster (Cotoneaster dammeri C.K. Schneid.), 'Flaviramea' dogwood (Cornus sericea L.), 'Lynwood' forsythia (Forsythia ×intermedia Zab.), and 'Variegata' weigela (Weigela florida (Bunge) A. DC.)} were grown in trickle-irrigated containers with 100% pine bark (control) or with 10 other pine-bark-amended media, including two sources (Noranda Forest (NF) and Quebec and Ontario (QO)) of raw paper mill sludge mixed at 15 % or 30% (by volume). All species grew equally well or better in the sludge-amended media than in the control or other nonsludge media. Cotoneaster and forsythia grew more in NF sludge media than in corresponding QO media due primarily to the greater quantities of N and other nutrients released from the NF sludge.