A Flora locale guidance note
Flora locale 15/11/1999
© Flora locale (UK) 6 December 1999
This Technical note may be downloaded and distributed electronically or by simple photocopies but may not be published or sold for commercial gain. The guidance has been updated and presented more concisely in our document Go Native! Planting for biodiversity (guidelines).
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2 Sensitive localities
2.1 Designated land
2.2 Grassland creation
2.3 Heather and heathland restoration
2.4 Ancient hedgerows
2.5 Hedgerow restoration - general
2.6 Ancient woodlands
2.7 Other semi-natural woodlands and new native woodlands
2.8 Coastal sites, islands and ecologically isolated localities
3 Less sensitive localities
4 Locating plants and availability
So you know what species you want to establish or grow on your site? But where should you source your plants and seed from?
Flora locale considers that you should care about how you source your plants, so as to:
In overview of issues concerning the sourcing and use of native plants we have explained some of our concerns relating to the use of introduced forms and varieties of native species, and discussed why genetic variability and associated adaptation in native species is important. Below we again outline some of the issues, then outline our recommended approaches for sourcing of planting material for different types of schemes.
Sensitive localities are defined as localities which hold:
Examples of sensitive localities are:
Other land where ancient and well adapted native plant communities are found; in the UK these include:
* (UK Biodiversity Group. 1998. UK Biodiversity group Tranche 2 Action plans Volume II terrestrial and freshwater habitats.
The following strategies should be used on or adjacent to designated land (in a British context this would be a Site of Special Scientific Interest):
The strategy chosen will depend upon individual circumstances.
As a general principle, seed and plants sourced from outside a designated site should not be introduced to the site. If there has been a problem of erosion or other damage, the priority must be to attend to the causes, and use physical or other means (e.g. reducing livestock densities) to address the problem prior to seeding or plug planting vegetation from other parts of the site. Habitat management, and management of activities that have caused the damage, should be the initial recourse, followed by seeding or planting where damage is severe.
Agri-environment schemes close to species rich grassland should refrain from using wildflower seed sourced from other localities. The following strategies are advised:
Fodder varieties of wildflower species should be avoided in all schemes which have wildlife enhancement as at least one of their objectives and should never be purchased or substituted for the wild type.
Using agricultural varieties of grasses
Over recent centuries, the majority of commonly found grasses of agricultural value have been subject to considerable manipulation by selective breeding. Today, only a few seed merchants currently sell seed that is of known British native origin and local provenance. Because these grasses have been so widely used over a long period, the use of agricultural grass varieties is not considered to be as important an issue as the use of wildflower cultivars. However, Flora locale hopes that supplies of native origin grass seed will increase over succeeding years and emphasises that, wherever possible, seed of native origin and local provenance should be used where seeding is carried out within or close to sensitive localities.
Precautions should be undertaken when harvesting wild seed from a species-rich grassland, to ensure that the existing grassland is not damaged. For guidelines on harvesting seed from wildflower meadows see Crofts & Jefferson and the website section Seed Collection and Plant Propagation.
Strewing freshly cut hay from species-rich meadows is another approach that has been successfully used to enhance the botanical diversity of herb poor grassland, but partial destruction of the original (receiving) sward is usually necessary (e.g. using a graminicide or by stripping turf) to allow bare ground in which the seed can establish. Yellow Rattle (Rhinanthus minor) can also be sown into existing grassland to reduce grass growth and open the sward. Further details on this and other approaches is to be found in Crofts & Jefferson).
Enhancement tends to be more successful on sites with lower fertility and in swards that still contain a good variety of native grasses (and correspondingly more difficult on rye grass-clover swards which are highly fertile).
There have been circumstances when seeding is due to take place adjacent to a botanically important site, such as a coastal grassland SSSI, but when no local seed has been available. The most appropriate approach to dealing with this type of situation is to sow widely available agricultural varieties (not horticultural ones) of fine-leaved native grass species that reflect those found in other permanent grasslands in the area.
Examples of fine-leaved native grass species for re-creating wildflower grasslands
Red Fescue (Festuca rubra) Crested Dog's-tail (Cynosurus cristatus)
Small Timothy (Phleum bertolonii) Common Bent (Agrostis capillaris)
Yellow Oat-grass (Trisetum flavescens) Sweet Vernal-grass (Anthoxanthum odoratum)
These species are suitable for dry grasslands and lowland meadows on a range of soil types.
Once this sward is established, it can be augmented with wildflower and native grass seed collected from native plant communities in the locality, ensuring that bare ground is first created into which the seed is then sown. Grazing will help the spread and establishment of wildflowers. White clover, or agricultural varieties of other clover species, should not be used.
Road verges and land associated with highways
Where land disturbance results from highways developments, such as construction of a new highway, plant sourcing should pay close attention to the characteristics of the surrounding vegetation. In general, topsoil should not be imported as this tends to be highly fertile, favours noxious weeds and the development of a plant community that is out of character.
Wherever possible, natural regeneration should be encouraged or seeding and planting should involve the collection of seed from the local area (this can be bulked up using the resources of a local or other specialist nursery). Highways schemes take a considerable number of years to proceed, so there should be ample time to undertake the specialist seed collections that are needed and this aspect of landscape design should be incorporated into the earliest stages of the scheme design.
Further detailed advice on roads is available in Scottish Government and Highways Agency publications.
Restoration of heather swards on degraded heath or moor may also benefit from seeding, but if the primary reason for deterioration is overgrazing, this must be addressed first. Lower stocking rates for livestock (about 1 sheep per ha in uplands) may be all that is needed to promote heather recovery, even on moorlands which have become grass-dominant in living memory. Sources of heather seed for heathland and moorland restoration should ideally be local and collected under specific contracts by mechanical seed harvesting, or by cutting heather stands containing seed heads, baling this up and then spreading it on donor sites. Heather seed collected in this way should be taken directly to the receiving site, as it will rapidly deteriorate unless it is professionally cleaned and put into cold storage. For lowland heaths, intense summer fires (usually arson attacks) and lack of grazing are two problems that should be addressed before heather seeding is undertaken. Research by Meikle (1999) suggests some genetic variation in heather (Calluna vulgaris) populations related to geographical location.
Ancient hedgerows that contain six or more woody species, may represent fragments of the original wildwood which cloaked the British Isles before people cleared the land for agriculture. Their restoration should be carried out sensitively. Unfortunately, a significant amount of recent restoration has involved planting shrubs and trees of introduced origin, as well as species that haven't reflected the composition of the original hedge. As a result many hedgerows, which ought to provide a valuable historical record, have been altered for the first time in centuries.
The most desirable strategy for hedgerow restoration is to use trees and shrubs of native origin, preferably grown from seed sourced from local ancient woodlands, ancient hedgerows or scrub within the same local biogeographic region and seed zone (the seed zone, which is designated by the Forestry Commission, and the local biogeographic region will overlap but have different boundaries).
The species chosen should also reflect the existing mix of species that are present in the hedge.
A landowner could keep costs down by collecting the seed him/herself and growing it on a plot situated on the farm. Alternative, a local nursery could be contracted to carry out seed collection, should appropriate material be unavailable "off-the-shelf". Guidance on tree and shrub seed collection is available in the Forestry Commission Practice Note on Using Local Stock for Planting Native Trees and Shrubs and in this website.
The degree of care taken over sourcing will need to closely reflect the needs of individual sites and circumstances, but the priority is not to obscure the historical character of the locality by imposing something that will be completely different and out of character.
Hedgerow restoration, including the planting of new hedgerows, should aim to plant a mixture of hedgerow shrubs appropriate to the local context. Once well established, to the extent that the new hedge is casting a reasonable degree of shade (probably after about six years), the reintroduction of hedgerow herbs can also be considered. These could also be grown from seed collected from local woods. Only plants that are very abundant in the locality should be used for this purpose.
Agricultural practices, such as herbicide spray drift, fertiliser spinning and heavy grazing will prevent the re-establishment of hedgerow ground flora. Ground flora plantings should not be carried out if any of these practices affect the hedgerow.
Trees and shrubs should not normally be planted in ancient semi-natural woodlands, where natural regeneration is the preferred approach for restoration. These are special places. Here, grants from the public sector are better directed towards deer fencing than planting and paying for the intensive management that planting requires. Rather too many ancient woodlands have been damaged by inappropriate planting schemes and are now full of regimented ranks of "weed-free" trees of unknown native origin (while naturally regenerated trees have been viewed as "weeds" and have been cut down from around the planted ones). This in turn poses future problems for collecting seed from trees in these woodlands, as it becomes increasingly difficult to identify which trees and shrubs are native to the site and reflect "wild" examples.
Leaving a substantial amount of dead wood on the ground, rather than the usual "tidy woodland" approach is particularly important for encouraging natural regeneration, especially in heavily deer-grazed woods where a tidy approach by woodland managers has created a dearth of dead wood. Fallen branches and the mass of tangled twigs associated with the crown and root plate of a dead tree, provide structures for bramble and other climbing plants, and good protection for young tree seedlings - away from browsing deer. Leaving dead wood around also restores important nutrients to the woodland soil, that can be used by seedlings and other young trees.
Ancient woodlands which have been severely degraded, and where there are rather few seed bearing trees and shrubs present, will require replanting. Under these circumstances trees and shrubs should be grown from seed selected from intact semi-natural ancient woodlands, native scrub or ancient hedgerows in the locality that are situated on similar soils and with similar drainage characteristics.
Information about how to identify whether an ancient woodland is ancient or not, plus the county and regional Ancient Woodland Inventories, is available from offices of the country nature conservation agency and may be available on line (e.g. from the Magic website).
The UK Forestry Standard (Forestry Commission, 1998) and associated Forestry Practice Guides nos. 1-8 (The Management of Semi-natural Woodlands) recommend using plants of local provenance, preferably from semi-natural parent trees (i.e. preferably grown from seed collected from trees and shrubs of native origin). The UK Woodland Assurance Scheme also seeks the use of seed of local (native) origin for restocking and planting semi-natural woodlands where this is available and considered appropriate. The Forestry Commission Practice Note Using Local Stock for Planting Native Trees and Shrubs provides further guidance on sourcing planting material for replanting semi-natural woodlands or for planting new native woods.
There are many some examples of plant species which have varieties that are specially adapted or endemic to coastal situations and islands, so special care should be taken when introducing plants in these areas.
Ideally, the precautionary principle should apply, using a specialist to collect local seeds under contract to grow on and propagate/bulk up or sow directly on site. (Advice from a qualified native plant ecologist or local botanist should be sought in selecting the species to establish.)
Alternatively, a combination of natural regeneration and habitat management should be considered, where feasible.
There are also other isolated or characteristic localities, where ancient and well-established habitats, such as native grasslands, heath and woodland are found. The majority of these localities have been individually identified as local biogeographic regions or are Sites of Special Scientific Interest and include large areas such as the Chilterns (England), or smaller ones such as the Lizard (England) and Lleyn Peninsula (north Wales). The preferred sourcing strategy for these areas should be to use material of local native origin (or local provenance trees and shrubs where it is difficult to identify material of native origin).
Applying Flora locale's guidance in this Technical note will, we appreciate, be difficult in the short term. However, there is now a sea change in attitude about the importance of paying attention to plant sources and hopefully the availability of appropriate planting material is set to increase in years to come.
Document date: 15 November 1999
Flora locale gratefully acknowledges financial support provided by English Nature, the World Wide Fund for Nature and TRANSCO which enabled the production of this document.