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The effect of short interval cyclic flooding on root and shoot growth of ‘Shamrock’ inkberry holly (Ilex glabra), ‘Henry's Garnet’ sweetspire (Itea virginica), and ‘Winterthur’ possumhaw (Viburnum nudum) was studied in a greenhouse in Auburn, AL. Liners (4.4 inches long) of each species were planted into trade 1-gal pots in 1 pine bark:1 peat by volume (PB:P) or fine textured calcined clay (CC). ‘Shamrock’ inkberry holly and ‘Henry's Garnet’ sweetspire were planted 18 Apr. 2008; the experiment was repeated with the addition of ‘Winterthur’ possumhaw on 16 June 2008. Plants were flooded to substrate level for 0 (non-flooded), 3, or 7 days. Flooding cycles were repeated at least five times with 7 days of draining between each flood cycle. During draining, plants received no irrigation. Non-flooded plants were watered as needed. Flooded plants for all species except ‘Winterthur’ possumhaw showed decreased root dry weight, shoot dry weight, and final growth index when compared with non-flooded plants. Survival was higher in CC than PB:P for both experiments. All plants maintained good visual quality and shoot growth. As a result, overall, these plants seemed tolerant of flooding despite differences in growth.
Greywater is a renewable irrigation alternative to potable water; however, its use as an irrigation source is limited by the potential for salt injury to plants. Research was conducted to determine salt tolerance of three common landscape species, small anise tree (Illicium parviflorum), ‘Henry’s Garnet’ sweetspire (Itea virginica), and muhly grass (Muhlenbergia capillaris). Two experiments were performed, one with high sodium chloride (NaCl) concentrations and one with low NaCl concentrations. Plants received daily irrigation of tap water containing one of the following NaCl concentrations: 0 (tap water); 2000, 4000, 6000, 8000, or 10,000 mg·L−1 (high NaCl); or 0 (tap water), 250, 500, or 1000 mg·L−1 (low NaCl) for 15 weeks. Plants were harvested after 5, 10, or 15 weeks. Root dry weight (RDW) and shoot dry weight (SDW) were determined at each harvest; survival was determined at experiment termination. Leaf tissue was analyzed for tissue macronutrient [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and, magnesium (Mg)], sodium (Na), and chlorine (Cl) concentrations in the high NaCl concentration experiment. With high NaCl, RDW and SDW decreased with increasing NaCl for all species. Anise and sweetspire had low or no survival, respectively, at the highest NaCl concentration; muhly grass had 100% survival regardless of treatment. In general, leaf macronutrient, Na, and Cl increased with increasing NaCl concentration. With low NaCl, there was no effect of NaCl concentration on RDW or SDW for all species. All three species continued to grow between harvest dates in the lower NaCl concentration experiment, whereas only anise and muhly grass continued to grow with high NaCl. Anise and muhly grass were tolerant of saline irrigation that could be expected from greywater. Sweetspire exhibited symptoms of salt stress (necrotic leaves and leaf drop, visual observation) at all NaCl concentrations including the lowest (250 mg·L−1), and should not be irrigated with saline water.