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Calvin Chong and Bob Hamersma

Terminal stem cuttings of four evergreens [arborvitae (Thuja occidentalis L.), `Calgary Carpet' juniper (Juniperus sabina L.), `Hetzii' juniper (Juniperus virginiana L.), and Tamarix juniper (Juniperus sabina L.)] and four deciduous {Amur maple (Acer ginnala Maxim.), common lilac (Syringa vulgaris L.), ninebark [Physocarpus opulifolius (L.) Maxim.], and viburnum (Viburnum farreri Stearn)} woody landscape shrubs were treated with 0%, 0.1%, 0.3%, or 0.8% IBA mixed in talc or with 0%, 0.25%, 0.5%, 1.0%, or 1.5% IBA dissolved in 95% ethanol, radiator antifreeze (95% ethylene glycol), or windshield washer fluid (47.5% methanol). None of the carriers were phytotoxic to the cuttings. Cuttings treated with IBA in radiator antifreeze or windshield washer fluid produced rooting in most taxa similar to those treated with IBA in ethanol. Cuttings of the evergreen taxa produced more roots with liquid than with talc IBA at similar concentration ranges. There were some differences in rooting performance (expressed in terms of percent rooting, mean root count per rooted cutting, and length of the longest root per cutting) of taxa to solvents and IBA concentrations. However, such differences, if any, were generally small or commercially insignificant, except for ninebark, which rooted optimally with no IBA and exhibited a large reduction in percent rooting with increasing IBA concentrations in windshield washer fluid. Chemical name used: indolebutyric acid (IBA).

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Calvin Chong and Bob Hamersma

Stem cuttings of seven deciduous landscape shrubs {silky dogwood (Cornus amomum Mill.), coralberry (Symphoricarpos orbiculatus Moench), Peegee hydrangea (Hydrangea paniculata Siebold. `Grandiflora'), Bridal-wreath spirea [Spiraea ×vanhoutteii (C. Briot) Zab.], spirea (Spiraea ×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 of 10%, 20%, 30%, 40%, 50%, or 60% (v/v) of raw paper mill sludge and perlite. There was a large linear reduction in percent rooting of viburnum (from 80% to 21% with 0% and 60% sludge, respectively) in response to increasing level of sludge. The mean root count per cutting also was significantly decreased, from 14 to 5. However, the length of longest root was unaffected. In contrast, all the other species ranked good to excellent in rooting, regardless of the level of sludge. Differences, if any, in rooting performance were not of practical significance.