RAW PAPER-MILL SLUDGE IN A ROOTING MEDIUM FOR DECIDUOUS WOODY CUTTINGS

Stem cuttings of seven deciduous landscape shrubs (silky dogwood (Corn us amomum Mill.), coralberry (Symphoricarpos orbiculatus Moench), Peeg ee hydrangea (Hydrangea paniculata Siebold, 'Grandiflora'), Bridal-wre ath spirea [Spiraea x vanhoutteii (C. Briot) Zab.], spirea (Spiraea x bumalda Burv. 'Goldmound'), fragrant viburnum (Viburnum farreri Stearn ), and weigela [Weigela florida (Bunge) A, DC, 'Variegata Nana']} were rooted under mist in 100% perlite (no sludge) medium or in mixtures o f 10%, 20%, 30%, 40%, 50%, or 60% (v/v) of raw papermill sludge and pe rlite. There was a large linear reduction in percent rooting of viburn um (from 80% to 21% with 0% and 60% sludge, respectively) in response to increasing level of sludge, The mean root count per cutting also wa s significantly decreased, from 14 to 5. However, the length of longes t root was unaffected, In contrast, all the other species ranked good to excellent in rooting, regardless of the level of sludge, Difference s, if any, in rooting performance were not of practical significance.