Several approaches can be taken to minimize weed intrusion of wildflower plantings. To suppress existing weed seeds, the primary and most important cultural practice is proper seedbed preparation. Research has shown that short-term preemergent herbicides, multiple tillings, solarization, and fumigation can result in good weed control during the initial year of wildflower establishment. Other strategies include increased seeding rates, use of aggressive species, and selective herbicides.
Contrary to popular notion, many wildflower taxa are quite specific in their edaphic requirements. From a compilation of 35 species adapted to Georgia and the Southeastern U.S., several mixes have been formulated to meet the siting preference of these taxa whose persistence may be annual, biennial, or perennial. Mixes presented are suited for landscape color, partial shade, xeric, mesic, aggressive, and specialty uses.
No immunity to pickleworm damage was found among 40 plant introductions of muskmelon (Cucumis melo L). However, a Dudaim type, PI 273438, and two agrestis types, PI 137843 and PI 140471, showed significantly lower susceptibility in preliminary tests with 8 muskmelon botanical varieties.
A micropropagation system to obtain plants from inflorescences of pampas grass (Cortaderia selloana Schult. `Pumila') was developed. Factors examined included developmental stage of inflorescence cultured and growth regulator combinations and concentrations that support explant establishment, shoot regeneration, and rooting. Immature inflorescences ≈300 mm long formed many shoot primordia when initially cultured on Murashige and Skoog basal medium containing 4.5 μm 2,4-D and 8.9 μm BA and subcultured to medium with 0.4 μm 2,4-D and 4.4 μm BA. Thereafter, monthly transfer to a medium without growth regulators yielded about three shoots per tube per month for more than 6 months. Most shoots rooted spontaneously and were easily hardened to greenhouse conditions. Field-tested plants flowered within 2 years and nearly all appeared identical to the parent cultivar. With this technique, several thousand plants can be obtained from a single inflorescence in 1 year. Chemical names used: N -(phenylmethyl)-1 H -purine-6-amine (BA); (2,4-dichlorophenoxy)acetic acid (2,4-D).
About a quarter of the plant introductions of muskmelon (Cucumis melo L.) reported resistant to powdery mildew were as resistant to Sphaerotheca fuliginea race 2 as ‘PMR6’ and ‘Georgia 47’; about half were intermediate in resistance and the other quarter were susceptible. PI 234607, ‘Georgia 47’, and ‘PMR6’ were considered the most useful because of high resistance to race 2 and good quality.
Resistance to Sphaerotheca fuliginea (Schlecht) Poll, was not found in 292 plant introductions of Cucurbita pepo L. Cucurbita moschata Duch. ex Poir, PI 179925 and PI 201254, were resistant Most plant introductions of Cucurbita maxima were resistant
Eighty horticultural wildflower taxa were evaluated for performance at three locations over three years in Georgia (USDA climatic zones 7-9). Plant performance and persistence were rated as superior perennial/reseeding annual, secondary perennial, annual, and unadapted. Length of bloom season for each species was determined at each location. Forty-eight species were rated as superior, 11 as secondary, 14 annual, and seven were not adapted. From these data, specialty mixes for meadow gardens, roadside beautification, landscape color, and native plant restoration areas have been formulated for use in cost-efficient landscape plantings. The mixes contain 10-15 species with overlapping bloom seasons to provide color during most of the growing season of eight months.
All available U.S. Department of Agriculture plant introductions (PI) of pepper were screened and evaluated for their value as annual ornamentals. Eighteen accessions compared favorably with the plant and fruit characters of ornamental cultivars available in the seed trade. Varying plant statures, foliage colors, and fruit colors were noted. Two new Capsicum species are reported for ornamental peppers.
Immature inflorescences of Miscanthus sinensis Andress. `Gracillimus', `Variegatus', and `Zebrinus' were cultured on modified MS medium with 9.0 μm 2,4-D, 20 g sucrose/liter, 2.0 g Gelrite/liter, and 0.75 g MgCl2/liter. Organogenesis was observed 8 to 12 weeks after callus initiation. Shoots were rooted on half-strength MS medium without growth regulators. After rooting, tillers were initiated. When transferred to soil, plants matured to flowering quickly and retained their variegation patterns. Propagation through in vitro tillering is suggested. Chemical name used: 2,4-dichlorophenoxyacetic acid (2,4-D).