Four deciduous ornamental shrubs [`Coral Beauty' cotoneaster (Cotoneaster dammeri C.K. Schneid); Tartarian dogwood (Cornus alba L.); `Lynwood' forsythia (Forsythia × intermedia Zab.); `Variegata' weigela (Weigela florida Bunge A.D.C.)] were grown in trickle-fertigated containers. There were eight media consisting of 25% or 50% sphagnum peat or composted pine bark, 25% sand, and the remainder one of two sources of spent mushroom compost; four media with 509″ peat or bark mixed with 50% spent mushroom compost; and a control medium of 10070 pine bark. Initially, higher than desirable salt levels in all compost-amended media were leached quickly (within 2 weeks of planting) and not detrimental to the species tested. Unlike cotoneaster, which showed no difference in growth (shoot dry weight) due to medium, dogwood, forsythia, and weigela grew significantly better in all compost-amended media than in the control. Growth of these three species was 20% greater in peat-based than in bark-based, compost-amended media. Dogwood and forsythia grew slightly more (+8%) with spent mushroom compost based primarily on straw-bedded horse manure than with one based on a blend of straw-bedded horse manure, wheat straw, and hay. The addition of sand (25%) to a mixture of 50% peat or bark and 25 % spent compost produced a medium with minimal compaction.
Calvin Chong, R.A. Cline and D.L. Rinker
Calvin Chong, R.A. Cline, D.L. Rinker and O.B. Allen
`Eight deciduous ornamental shrubs-deutzia (Deutzia gracilis Siebold & Zucc.), dogwood (Cornus alba L. `Argenteo-marginata'), forsythia (Forsythia × intermedia Zab. `Lynwood Gold'), ninebark [Physocarpus opulifolius (L.) Maxim.], potentilla (Potentilla fruticosa L. `Red Ace'), privet (Ligustrum vulgare L.), rose (Rosa L. `John Frank. lin'), and weigela [Weigela florida (Bunge) A. DC. `Variegata Nana']—were grown in trickle-irrigated containers with 100% bark (control) or with bark and 33%, 67%, and 100% (by volume) of each of three sources of spent mushroom compost (unweathered, weathered, and unweathered compost leached with water). Despite large variation in species growth response to sources and levels of compost, most grew equally well or better in the compost-amended regimes than in 100% bark and were influenced little, or not at all, by initial or prevailing salt levels in the media. Shoot and root dry weight of dogwood, forsythia, ninebark, rose, and weigela (all sources), and shoot dry weight of deutzia and potentilla (weathered source only), increased linearly or curvilinearly with increasing compost levels. The reverse relationship occurred (all sources) in shoot and root dry weight of privet and root dry weight of weigela and potentilla. Leaf nutrients (N, P, K, Ca, Mg, Fe, Mn, and Zn) tended to increase with increasing compost levels, but not all species showed this response with all nutrients. Regardless of compost source or level, all shrubs were of marketable quality when harvested, except privet, which showed leaf chlorosis in all compost-amended regimes.