- Family: Plumbaginaceae
- Habit: Perennial herb
- Flowering season: July to September
- Tier 2 – Eradication – High and very high impact species, or potentially so, with low enough abundance to make eradication feasible within LIISMA. Highest level of rapid response efforts. Need delineation surveys and citizen science to determine the full extent.
Means of Introduction
Native to Europe and can be found along the coasts of the United Kingdom, it was likely introduced through the horticultural trade. Where it was first discovered in 2017 in East Hampton, NY, it was found alongside nursery tags, pointing towards it likely having been planted. It is likely spread through wind, with potential for spread via waterways and watercrafts.
Habitat
Rock sea lavender is found growing in the tidal high marsh and the adjacent area, among native sea lavender (Limonium caroliniana), phragmites (Phragmites australis), marsh elder (Iva frutescens), groundsel tree (Baccharis halimifolia), and eastern red cedar (Juniperus virginiana). Grasses include salt meadow grass (Spartina patens) and spike grass (Distichlis spicata). Rock sea lavender seems to be able to grow farther inland than the native Limonium caroliniana and may be less tolerant of salty conditions and prolonged inundation.
Description
The spoon shaped leaves with 1-3 veins are arranged in a basal rosette, fleshy and variable in size – from 0.7” to 4.7” long and broad. Stems leaf-less and flowering stems are alternately branched, with a zig-zag appearance. Flowers purple, arranged in spikes on stiff stems. Unopened flower buds have more of a white coloration. Rock sea lavender is smaller and has flowering stems that are more branched than that of common sea lavender. Grows up to 19” tall.
Impacts
The impacts of this plant are largely unknown, but it’s ability to rapidly colonize ecologically important and rare habitats is cause for concern. There are a handful of invasive Limonium spp that are considered invasive on the west coast, and one study found that where Limonium ramosissimum subsp. provinciale is present, the native halophytes (namely Salicornia pacifica, Jaumea carnosa, and Distichlis spicata) all declined significantly (Archbald et. al 2014). More research would need to be done to see if this species of Limonium is having the same effect on our native east coast halophytes. Anecdotally, it has been seen competing with the native sea lavender, though it appears to prefer shadier spots directly beneath marsh sea elders (Iva fructens) and eastern red cedars (Juniperus virginiana) than its native congener. It may also compete with other herbaceous vegetation within its range on the marsh such as prickly pear cactus. The sea lavender genus also exhibits high hybridization potential, which could impact the genetic integrity of the native sea lavender (Palacios & González-Candelas 2002).
Control
Hand pulling in the early summer when rosettes first appear has proven to be the best method of control in this smaller infested area on Long Island. Removing seed heads can also help reduce the spread of seeds in areas with larger infestations where pulling may not be permitted so as to not disrupt the tidal shoreline.
Known issues
Powdery mildew
Sources:
Archbald, Gavin & Boyer, Katharyn. (2014). Distribution and Invasion Potential of Limonium ramosissimum subsp. provinciale in San Francisco Estuary Salt Marshes. San Francisco Estuary and Watershed Science. 12. 10.15447/sfews.2014v12iss2art6.
Palacios C, Rosselló JA, González-Candelas F. Study of the evolutionary relationships among Limonium species (Plumbaginaceae) using nuclear and cytoplasmic molecular markers. Mol Phylogenet Evol. 2000 Feb;14(2):232-49. doi: 10.1006/mpev.1999.0690. PMID: 10679157.
