Low water landscapes are increasing popular and important in the urban areas of the Intermountain West (IMW). Perennial wildflowers are an essential part of low water landscapes, and are a dominant plant type in IMW native habitats. We compared pot-in-pot (PIP) vs. conventional above-ground (CAG) production of six IMW native wildflower species, Mirabilismultiflora, Aquilegia caerulea, Penstemon palmeri, Polemonium foliosissimum, Sphaeralcea grossularifolia, and Penstemonstrictus in #1 (4-L) containers. Media temperature, container-plant water loss, stomatal conductance, and growth were measured during two production cycles per year over 2 years. Growing medium temperatures in the PIP system averaged 10 °C cooler than in the CAG system. Consistent with cooler growing media, overall water loss of PIP-grown plants averaged 10% lower than plants grown in the CAG production system. Lower growing media temperatures apparently affected transpiration, as stomatal conductance was about 60% higher in the PIP system as compared to the CAG-grown plants. The integrated effect of lower growing media temperatures on plant performance resulted in about one-third greater top and root growth for plants growing in the PIP system compared to those in the CAG system. Pot-in-pot production may be an economically suitable nursery system for producing IMW native perennial wildflowers by reducing water loss and enhancing growth.
Guillermo Cardoso, Roger Kjelgren, Teresa Cerny-Koenig and Rich Koenig
Dina Margaret Samfield, Jayne M. Zajicek and B. Greg Cobb
Seeds of tickseed (Coreopsis lanceolata L.) and purple coneflower [Echinacea purpurea (L.) Moench] were primed in aerated solutions of distilled water or 50 or 100 mM salt (potassium phosphate, pH 7.0) at 16C for 3, 6, 9, or 12 days. Coreopsis seeds primed in the 50 mM buffer germinated the most rapidly and uniformly, and, under stress conditions in the greenhouse, resulted in a faster-growing, more-uniform crop than other treatments. Seeds primed in distilled water and the 50 mM buffer germinated faster and at higher rates at suboptimal temperatures in the laboratory than nonprimed seeds. Priming of Echinacea purpurea seeds for 6 or 9 days in distilled water or in the 50 mM buffer resulted in faster, more-uniform germination than other treatments. Seedling emergence under stress conditions was improved by all priming regimes, with best emergence occurring in treatments that lasted > 3 days. Priming also increased germination rates of E. purpurea at suboptimal temperatures in the laboratory.
Beth E. Engle, Arthur C. Cameron, Royal D. Heins and William H. Carlson
Storage of perennial plugs at subfreezing temperatures could be a valuable production tool since plants could be removed over relatively long periods for forcing. Several species of seed-propagated perennial plugs were pretreated at 0 and 5C under continuous 50 μmol·s-1m-2 PPF for 0, 2, 4, or 8 weeks. After each pretreatment period, plugs were placed into 4-mil polyethylene bags that were then sealed and placed at -2.5C for 0, 2, or 6 weeks. Plugs were then removed from the bags and placed into a 24C greenhouse for two weeks under ambient light levels and daylength, after which time they were rated for percent survival and general regrowth quality. Regrowth was not influenced by pretreatment temperature. Regrowth of Limonium dumosumtatarica, and Campanula carpatica `Blue Clips' following -2.5C storage was excellent with or without a pretreatment. Regrowth of Achillea filipendulina `Cloth of Gold,' Gaillardia grandiflora `Goblin,' and Iberis sempervirens `Snowflake' was improved on plugs given the 0 or 5C pretreatment. Hibiscus × hybrida `Disco Belle Mixed' regrowth was poor, regardless of pretreatment.
Jessica D. Lubell and Mark H. Brand
Epimedium is a genus of shade tolerant herbaceous perennials and groundcovers that are slow growing and command high prices. This research examined the influence of division size and timing on propagation success and growth of E. pinnatum ssp. colchicum Boiss., E. × rubrum Morren, E. × versicolor `Sulphureum' Morren and E. × youngianum Fisch. To determine an appropriate division size for each species, small (single bud) and large (three bud) divisions were made in mid-June 2002 and 2003. For the timing study, uniform divisions (three to five buds for E. pinnatum ssp. colchicum and E. × versicolor `Sulphureum'; four to seven buds for E. ×rubrum and E. × youngianum) were made in March, late June and late August, when plants were dormant, had just completed foliage expansion, or were summer dormant. Half of the plants were destructively harvested in the fall and half were overwintered and forced in the greenhouse in early spring. By the end of the growing season, plants grown from large divisions were larger than those grown from small divisions and had produced more buds, however, plants from small divisions produced more buds per initial bud than plants from large divisions, demonstrating a faster increase in growing points. For each species, March divisions produced more vegetative growth, buds, buds per initial bud and potential propagules than June and August divisions, by the end of the growing season. However, by the following spring, both March and June divisions had produced plants of similar size and appearance, while plants grown from August divisions were smaller and of lower quality.
Beth A. Fausey, Royal D. Heins and Arthur C. Cameron
The growth and development of Achillea ×millefolium L. `Red Velvet', Gaura lindheimeri Engelm. & Gray `Siskiyou Pink' and Lavandula angustifolia Mill. `Hidcote Blue' were evaluated under average daily light integrals (DLIs) of 5 to 20 mol·m-2·d-1. Plants were grown in a 22 ± 2 °C glass greenhouse with a 16-h photoperiod under four light environments: 50% shading of ambient light plus PPF of 100 μmol·m-2·s-1 (L1); ambient light plus PPF of 20 μmol·m-2·s-1 (L2); ambient light plus PPF of 100 μmol·m-2·s-1 (L3); and ambient light plus PPF of 150 μmol·m-2·s-1 (L4). Between 5 to 20 mol·m-2·d-1, DLI did not limit flowering and had little effect on timing in these studies. Hence, the minimum DLI required for flowering of Achillea, Gaura and Lavandula must be <5 mol·m-2·d-1, the lowest light level tested. However, all species exhibited prostrate growth with weakened stems when grown at a DLI of about 10 mol·m-2·d-1. Visual quality and shoot dry mass of Achillea, Gaura and Lavandula linearly increased as DLI increased from 5 to 20 mol·m-2·d-1 and there was no evidence that these responses to light were beginning to decline. While 10 mol·m-2·d-1 has been suggested as an adequate DLI, these results suggest that 15 to 20 mol·m-2·d-1 should be considered a minimum for production of these herbaceous perennials when grown at about 22 °C.
Sonali R. Padhye and Arthur C. Cameron
The wholesale value of herbaceous perennials produced in the United States has grown by 63% in the last 5 years, reaching over $708 million in 2005 ( U.S. Department of Agriculture, 2006 ). This increase in sales of herbaceous perennials can at
Ling-cheng Jian, Jiang-ming Deng, Ji-hong Li and Paul H. Li
Seasonal alteration of the cytosolic and nuclear Ca2+ concentrations of spruce (Picea engelmannii Parry) and brome grass (Bromus inermis Leyss) was investigated by the antimonate precipitation cytochemical technique. Electron microscopic (EM) observations revealed that electron-dense Ca2+ antimonate deposits, an indication of Ca2+ localization, were seen mainly in the vacuole, the cell wall and the intercellular space in samples of both species, collected on 14 July 1997. Few deposits were found in the cytosol and nuclei, showing a low resting level during summer months. On 8 Aug. 1997 following a decrease in daylength of 1 hour and 12 minutes, Ca2+ accumulation was initiated in spruce with increased cytosolic and nuclear Ca2+ deposits, but not in brome grass. On 8 Sept. 1997, Ca2+ accumulation occurred in the cytosol of brome grass. This followed a drop in ambient temperature to 12 °C. Cytosolic and nuclear Ca2+ deposits continued to increase in spruce. Controlled experiments confirmed that it was the low temperature, not shortening daylength, that triggered Ca2+ accumulation in brome grass. High cytosolic and nuclear Ca2+ concentrations lasted about three months in spruce from early August to early November. However, the high cytosolic and nuclear Ca2+ concentrations in brome grass lasted only about 20 days from early September to the end of the month. During winter and spring, both species had low resting cytosolic and nuclear Ca2+ concentrations. The relationship between the duration of the high cytosolic and nuclear Ca2+ concentrations and the status of the developed dormancy/cold hardiness is discussed in light of current findings.
Shuyang Zhen, Stephanie E. Burnett, Michael E. Day and Marc W. van Iersel
often affected by factors other than plant water needs such as labor costs, the irrigation system being used, and the way irrigation is automated. In addition, water requirements for most herbaceous perennials remain unclear. As a result of lack of
Sonali R. Padhye and Arthur C. Cameron
yet characterized T opt for all the listed flowering responses in one species. Campanula ‘Birch Hybrid’, an interspecific cross of Campanula portenschlagiana and C. poscharskyana , is a hardy herbaceous perennial reported to exhibit a
Shana G. Brown and James E. Klett
The popular cultivar Snow Angel coral bells is a commercially important herbaceous perennial grown for its attractive white and green variegated foliage and bright pink flowers. To maintain the characteristic variegated foliage, ‘Snow Angel’ must be