Horticulturists and agronomists have a long history of using selective breeding to take advantage of intraspecific (within-species) variation with the goal of developing novel varieties of plant species. These efforts are responsible for the availability of countless improved food, forage, and ornamental varieties that are valued by farmers, landscapers, and home gardeners. In contrast, little attention has been paid to the idea of evaluating intraspecific variation to identify plants derived from a specific ecosystem (ecotypes) of native species that could improve the success rate of habitat restoration and enhancement projects, especially in aquatic systems. These projects often specify that plant material used for restoration be collected from local donor sites to preserve the area’s gene pool, but nearby source populations may be nonexistent or may not be well-adapted to conditions at the recipient (transplant) site. This paper, which summarizes information presented at the American Society for Horticultural Science Invasive Plants Research Professional Interest Group workshop in 2022, provides evidence that unimproved, wild-type species can be useful in aquatic habitat restoration and enhancement projects, particularly when conditions at sites targeted for restoration differ from those in nearby systems, or when sites are expected to undergo shifts in conditions because of factors such as climate change.
Conventional wisdom suggests that native aquatic plants have evolved to fill a specific ecological niche, and that their growth is regulated by environmental conditions or the presence of natural enemies that limit the distribution or abundance of the species. However, it is becoming obvious that native species are not always well-behaved and can develop populations that quickly reach nuisance levels that require management to avoid negative ecological impacts. This work summarizes information presented at the American Society for Horticultural Science Invasive Plants Research Professional Interest Group Workshops in 2017 and 2018, and it highlights the phenomenon of species that are considered both native and invasive in the aquatic ecosystems of Florida. These “natives gone rogue” are compared with the introduced species they mimic, and the consequences of excessive aquatic plant growth, regardless of the origin of the species, are described.
Wetland restoration is critical for improving ecosystem services, but many aquatic plant nurseries do not have facilities like those typically used for large-scale plant production. We questioned if we could grow littoral aquatic plant species in a variety of substrates and irrigation methods similar to those used for traditional greenhouse production. Plants were grown in pots with drainage holes that were filled with potting substrate, topsoil, coarse builders’ sand, or a 50/50 mix of topsoil and builders’ sand. These substrates were amended with 2 g of 15N–3.9P–10K controlled-release fertilizer per liter of substrate and were watered using either overhead irrigation or subirrigation. Plants were grown for 16 weeks, then scored for quality and height before a destructive harvest. Blue-eyed grass (Sisyrinchium angustifolium) and arrow arum (Peltandra virginica) performed best when subirrigated and cultured in potting substrate or sand. Golden club (Orontium aquaticum) and lemon bacopa (Bacopa caroliniana) grew best when plants were cultured in potting substrate and maintained under subirrigation. These experiments provide a framework for using existing greenhouses to produce these littoral species and give guidance to growers who wish to produce plants for the restoration market.
Wetland restoration is an important way to improve ecosystem services, but many wetland nurseries lack the facilities that are traditionally used to produce large numbers of native plants used in these projects. Our goal was to evaluate growth and performance of four wetland species in a variety of substrates, fertilizer regimes, and irrigation methods under greenhouse conditions. Plants were grown in pots with drainage holes filled with one of four substrates (potting substrate, topsoil, sand, 50/50 mix of topsoil, and sand) amended with 0, 1, 2, or 4 g of 15N–3.9P–10K controlled-release fertilizer per liter of substrate. Irrigation was supplied via an overhead system or subirrigation. After 16 weeks of production, plants were scored for visual quality and plant height before a destructive harvest. Broadleaf sagittaria (Sagittaria latifolia) was mostly unaffected by substrate type but performed best when subirrigated and fertilized with 4 g·L−1 of fertilizer. Growth of skyflower (Hydrolea corymbosa) and cardinal flower (Lobelia cardinalis) was best when fertilized with 2 or 4 g·L−1 of fertilizer and grown using overhead irrigation. String lily (Crinum americanum) was unaffected by substrate type but produced the largest plants when subirrigated. These experiments provide guidance for cultivating these wetland species under greenhouse conditions, which may allow growers to efficiently produce plant material needed for the restoration market.
Stokes aster is a herbaceous perennial native to the southeastern United States. Stokesia is a monotypic genus belonging to the tribe Vernonieae Cass. (family Asteraceae Dumont). The level of genetic diversity within the genus is unknown. The goal of this study was to determine the level of genetic diversity and relatedness among cultivars of stokes aster. The genetic relatedness among 10 cultivars of stokes aster, one accession of Vernonia crinita Raf. (syn. V. arkansana DC.), and one accession of Rudbeckia fulgida Ait. var. sullivantii (Beadle et Boynton) Cronq. `Goldsturm' was estimated using 74 randomly amplified polymorphic DNA (RAPD) primers. Similarity indices suggest that cultivars of stokes aster are very closely related, with values for all pairwise comparisons of cultivars of stokes aster ranging from 0.92 to 0.68. One cultivar, `Omega Skyrocket', had markedly lower similarity indices from the other cultivars, ranging from 0.72 to 0.68. Similarity indices between stokes aster and Vernonia and between stokes aster and Rudbeckia were 0.44 and 0.50, respectively.
‘Miami Beauty’ anthurium (Anthurium andreanum), ‘Frieda Hemple’ caladium (Caladium ×hortulanum), ‘Debbie’ spathiphyllum (Spathiphyllum), and ‘Regina Red’ syngonium (Syngonium podophyllum) were irrigated with water treated with bispyribac-sodium, quinclorac, topramezone, and trifloxysulfuron to identify herbicide concentrations that cause phytotoxic effects. Plants were irrigated four times over a 11-day period with the equivalent of 0.5 inch of treated water during each irrigation and were then irrigated with well water until they were harvested 43 days after the first herbicide treatment. Visual quality and dry weight data revealed that caladium was the most sensitive of the foliage plants, regardless of herbicide mode of action. Noticeable reductions in visual quality and dry weight of caladium were evident after exposure to 182, 144, 186, and 1135 ppb of bispyribac-sodium, quinclorac, topramezone, and trifloxysulfuron, respectively. Of the four herbicides evaluated in these experiments, only quinclorac caused noticeable damage to plants when applied at a concentration similar to the proposed use rate.