Short description of Sarracenia purpurea, Pitcher Plant

Plants comprise a large rosette of up to 100 pitchers, depending on age, which are filled with rainwater and host an aquatic inquiline community comprising of a variety of insects, algae and bacteria. These capture and decompose prey.

Impact summary: Sarracenia purpurea, Pitcher Plant

Physical displacement of associated liverworts, mosses and vascular plants and increased mortality of heathland/mire fauna.

Habitat summary: Sarracenia purpurea, Pitcher Plant

Bogs, poor fens and seepage mires.

Overview table

Environment	Terrestrial
Species status	Non-Native
Native range	Northern America
Functional type	Land plant
Status in England	Non-Native
Status in Scotland	Non-Native
Status in Wales	Non-Native
Location of first record	v.c.H25
Date of first record	1906

Origin

North America; native from Delaware to sub-Arctic Canada.Sarracenia purpurea has been in cultivation in GB since at least 1640 but was not recorded in the wild until 1892 when it was discovered growing on a bog near Lisduff in Ireland. In England it appears to have been first introduced to Wedholme Flow in the 1940s, possibly using material from established populations in Ireland, and was certainly well established by the 1970s. In Scotland it was first recorded as established in 1991.

First Record

Although there is no direct evidence it is suspected that all extant and eradicated populations originated from plantings by gardeners or carnivorous plant enthusiasts. These were probably as transplants from private collections or other established sites, but increasingly it appears to be originating from seed mixtures sold by commercial suppliers.

Pathway and Method

Reported as invasive where introduced in North America and in 12 countries in Europe (Austria, Belgium, Czech Republic, Denmark, England, France, Germany, Irish Republic, Northern Ireland, Scotland, Sweden, Switzerland). It has also been reported as established in New Zealand.

Species Status

Dispersal Mechanisms

The majority of seed is dispersed within a few metres of the parent plants, although secondary dispersal over greater distances is likely to occur along water-courses or across mire and bog surfaces during flooding events.

Reproduction

Although shortly rhizomatous, reproduction appears to be exclusively from seed. The flowers are insect pollinated (protandrous) but selfing of neighbouring flowers on the same plant (geitonogamy) is probably more common as the plants are known to be self-compatable. Seed production is prolific (500-1500 seeds per flower) and seed survival in peat may be up to five years.

Known Predators/Herbivores

None known.

Resistant Stages

None known.

Habitat Occupied in GB

Mostly raised (ombrogenous) or valley (soligenous) mires, but it has also been recorded from blanket bog in Scotland (Rannoch Moor). Established populations are almost always associated with permanent open water (e.g. wet runnels, bog pools), or ground liable to flooding in the winter (e.g. hollows in mire surfaces).

There are currently at least 12 established populations in GB. In only three of these do numbers exceed 1,000, and in only one site do numbers exceed 10,000 (Wedholme Flow). It has been eradicated (or nearly so) from a further 10 sites including Holmsley Bog in the New Forest where ongoing control measures have been required due to recruitment from the seedbank. Populations in North America and Ireland that have been established for much longer, and are generally much larger, suggesting that numbers can increase exponentially after a long lag phase.

Environmental Impact

Large populations of Sarracenia purpurea can reduce the cover of native species, especially mosses and liverworts in bog and mire habitats. Work in Ireland has shown that it can restrict the growth of Spaghnum thereby reducing peat formationAs a carnivorous plant it is also likely to have an impact on native insect communities although currently the evidence for this is anecdotal.

Health and Social Impact

Although potentially invasive, Sarracenia purpurea has been preserved on may sites because of its scientific, aesthetic and educational value. In some cases this has made land-managers reluctant to remove it, or engendered negative feelings from the public when it has been eradicated.

Economic Impact

At present Sarracena purpurea has no economic impacts, except for the costs of control, which have largely been paid by land management organisations in charge of conservation sites (Natural England, National Trust, Forestry Commission).

Identification

Bailey, T. & MacPherson, S. 2016. Carnivorous Plants of Britain and Ireland. Redfern Natural History Productions Ltd., Poole.

Biology, ecology, spread, vectors

Ellison. A.M. & Parker, J.N. 2002. Seed dispersal and seedling establishment of Sarracenia purpurea (Sarraceniceae). American Journal of Botany 89, 1024-1026

Ne’eman, G., Ne’eman, R. & Ellison, A.M. 2006. Limits to the reproductive success of Sarracenia purpurea (Sarraceniaceae). American Journal of Botany 93, 1660-1666

Newell, S.J. & Nastase, A.J. 1998. Efficiency of insect capture by Sarracenia purpurea (Sarraceniaceae), the northern pitcher plant. American Journal of Botany 85, 88-91

Management and impact

Sanderson, N. 2012. Ecological importance of Holmsley Bog in relation to the exotic pitcher plant Sarracenia purpurea. Report for the Hampshire and Isle of Wight Wildlife Trust on behalf of the New Forest Non-native Plants Project.

Walker, K.J. 2014. Sarracenia purpurea subsp. purpurea (Sarraceniaceae) naturalised in Britain and Ireland: distribution, ecology, impacts and control. New Journal of Botany 4, 33-41.

Walker, K.J., Auld, C., Austin, E. & Rook, J. 2016. Effectiveness of methods to control the invasive non-native pitcherplant Sarracenia purpurea L. on a European mire. Journal of Nature Conservation 31, 1-8.

General

McPherson, S. & Schnell, D. 2011. Sarraceniaceae of North America. Redfern Natural History Productions Ltd., Poole.

https://secure.fera.defra.gov.uk/nonnativespecies/downloadDocument.cfm?id=1416