Bracken Pteridium aquilinum
Bracken is a large, coarse, fern that is found almost worldwide and is native to Jersey. This shiny, green, fern can cover large areas of well drained land although it is particularly fond of hillsides. In our climate, bracken is deciduous, dying back over winter. In this way, the green summer landscape may become a bright orange-brown over winter. Often growing up to 2.5 metres in height, the underground rhizome may grow to over one metre in length.
Bracken is an extremely successful plant and is often one of the first colonists after a fire or after land has been disturbed. In Jersey we are seeing the establishment of large areas of bracken as it colonises farmland abandoned along our coast. This is particularly notable along the north coast where marginal lands, difficult to farm economically, have become a near bracken monoculture. Bracken’s dominance is further enhanced by the plant’s production of chemicals to inhibit other plant growth. Over time, the dead bracken stems and fronds that remain in winter develop deep beds that prevent other plants taking root in the soil beneath.
With little biodiversity in the bracken-dominated landscape, and little opportunity for invertebrates to survive in or on the tough fern stems and leaves, there are very few birds that can find any food in these areas. Only wrens Troglodytes troglodytes seem to thrive while other species like yellowhammer Emberiza citronella or skylark Alauda arvensis can no longer feed in what may have been ideal habitat only a few years before. The spread and subsequent dominance of bracken in former farmland may be one of the main reasons for the decline of several bird species inJersey.
Bracken is a tough, stubborn, plant well adapted to survive on Jersey. Control is very difficult and typically labour intensive and expensive. The fern’s dominance on often steep slopes makes a lot of obvious control measures very difficult.
See the bracken clearance project.
Hottentot Fig Carpobrotus edulis
The Hottentot fig, or ice plant, comes from South Africa and has been known in the Channel Islands since the mid 19th Century. In the past this attractive plant was intentionally propagated as an ornamental, garden, plant and to cover up some of our concrete fortifications. However, it rapidly spreads over coastal turf and cliff tops, swamping smaller, native, species and quickly reducing biodiversity and feeding opportunities for other wildlife. A large, spreading succulent, the fig forms mats of thick, green leaves with magenta or yellow flowers (there may be both on the same plant). The flowers later produce a reddish fruit, roughly fig-shaped, that is not edible in our climate (in South Africa it is used for making jam).
The Hottentot fig mats eventually take over the cliff tops to the extent that, when in flower, the plant can be seen from well out to sea. The brightly coloured cliff tops are typically admired by arriving visitors if not by conservationists. This plant will grow well where it is sunny, thrives in poor, sandy soil and is tolerant of salt spray.
Control of the Hottentot fig is not easy but can be very satisfying. The plant is often not deep rooted and large areas of the matting can be pulled up by hand. Teams of conservation volunteers can clear large areas of this plant but steep and inaccessible slopes may prove harder. In 2011-2012, 64.5 man/days were spent removing fig plants from La Lande du Ouest (Gorselands), Portelet and Noirmont. Often the shear quantity of plants pulled and piled up may prove the biggest challenge as they must be removed and, preferably, burned to prevent re-spreading. If anyone is thinking of planting this, often easily available, flower in their garden please don’t!
Other unwanted plants
It is all too easy for exotic plants to escape from gardens and establish themselves in the wild, especially where gardens lie alongside natural areas. Botanists are always surprised at the variety of different exotic plants they find and even the lay observer can pick out several plants that should not be there. Some of these plants may not be obviously harmful to the natural environment but many all too quickly become established and out-compete local plants while often offering nothing to local animals by way of food or shelter.
There are many such unwanted plants in Jersey including purple dew plant Disphyma crassifolium an, unfortunately very pretty, invasive succulent that is spreading across the coast. There is quite a spectacular patch on the escarpment between L’Étacq and Les Laveurs in St Ouen’s Bay. This plant is maybe not quite as vigorous as Hottentot fig, but it is still quite a problem and 49.5 man/days were used removing succulents from Les Blanche Banques alone in 2011-2012.
Holm oak Quercus ilex is widespread in Jersey especially on the dunes in St Ouen’s Bay and takes a lot of management each year. Although some older trees are left intact, many thousands of growing saplings are pulled up by hand each year. In 2011-2012, 258 man/days were dedicated to removing mature trees and saplings. Pampas grass Cortaderia selloana is a highly recognisable and highly invasive plant species that the coastlands could well do without. This grass that forms dense clumps is removed where possible but is difficult to totally eradicate. White stonecrop Sedum album is one of several non-native stonecrop species and is now widespread in Jersey and all may represent a threat to our native species. Japanese knotweed Fallopia japonica, is a very invasive plant and is widespread and even found on parts of the coast. This plant’s spread along banks etc. can be minimised by taking care when trying to clear it or during branchage – don’t strim it as this may cut it into a thousands of pieces which might all grow up in to new plants. New Zealand pigmyweed Crassula helmsii is an extremely invasive aquatic plant that has escaped from garden ponds and is potentially a major threat to native aquatic life – including threatened species like the agile frog Rana dalmatina. Spanish bluebell Hyacinthoides hispanica is widespread and hybridising with and outcompeting the native common bluebell Hyacinthoides non-scripta.