Hedge Guide Part 1: Planning and planting a new hedge Ulster Wildlife Trust

Transcription

1 Ulster Wildlife Trust Guide to Planning and Planting a New Hedge for Wildlife

2 Hedges in Northern Ireland The patchwork landscape of fields surrounded by high hedgerows is a traditional and familiar feature of Northern Ireland s countryside. Although man-made, hedges can be described as linear strips of woodland. They are vital habitats for wildlife and important for the visual quality of the landscape. Originally intended as fences and boundary markers, hedges have gradually become naturalised and now form a major component of the rural environment. Many date from the 18 th and 19 th century, but some originate from Tudor times. Hawthorn, a native shrub, was chosen as the most popular hedging plant because it can form a dense, stockproof hedge in a short period of time. Other trees and shrubs have gradually colonised older hedgerows, making them particularly important from a biodiversity point of view. Whilst most hedges in Northern Ireland contain hawthorn and ash, hedge style and composition varies in different parts of the country, helping to add local character and distinctiveness to an area. For example, upland areas in the Mournes and Sperrins will often have gorse hedges, whilst fuchsia is a common hedge species in coastal regions of Down and Antrim. In Fermanagh, the traditional hedge mix is hawthorn, willow and blackthorn. Hedges and Wildlife Hedges are valuable wildlife habitats in their own right, the combination of shrubs, trees and hedge bottom vegetation providing food and shelter for an enormous range of animals, from the smallest insects to top predators like barn owls. Our network of hedges thus represents an extremely important resource, especially when we consider that it occupies more land than all of our nature reserves put together. The term wildlife corridor is often applied to hedges, as they serve to link up wild areas, and provide a means by which both plants and animals can move between habitats. Hedges are refuges for many of our woodland and wayside flowers. You will often see bluebells, primroses and violets growing in the shade of a hedge, and grassy hedge bottoms are home to colourful vetches, stitchworts and taller herbs. Tussocks of grass and tall herbs are important overwintering sites for invertebrates and also provide good breeding conditions for many of our common butterflies. Spring blossoms, like the hawthorn or May flower, are vital nectar sources for early emerging insects, whilst hedge climbers like honeysuckle and ivy will provide food for insects later in the year. Hedges provide an excellent habitat for primroses and other woodland wildflowers The banks and ditches associated with many of our hedges are important habitats for amphibians and reptiles. The abundance of small mammals in hedgerows, including hedgehogs, field mice and pigmy shrews, make them excellent hunting territory for larger predators such as stoats, foxes and birds of prey. Bats may also be found moving along hedges, as they often use these linear features as navigational tools.

3 Over 30 of our bird species in Northern Ireland regularly utilise hedgerows, and some of our rare and declining species rely on properly managed hedges as a food source. Birds are attracted by the plentiful supply of insects and grubs, the autumn harvest of berries and nuts, and weed seeds in the hedge bottom. A well-maintained hedge with some mature trees will accommodate a variety of birds, each with different preferences in terms of nest and perch sites. Autumn berries are a valuable food source for the Yellowhammer, a species of conservation concern in Northern Ireland We are gradually losing the traditional hedges in our countryside as a result of removal and neglect. This trend can be reversed in two ways 1. Planting new hedges 2. Managing existing hedges Both actions will benefit wildlife and landowners alike. 1. Planting new hedges Benefits of planting a new hedge. Wildlife value (see text) Visually attractive Stockproofing fields Prevent direct animal contact to combat the spread of disease like bovine tuberculosis Shelter for livestock and crops Pest control, by attracting natural predators Screening and noise reduction Privacy and security Long lasting Choice of species to plant The first rule of thumb when choosing species for your new hedge is to look at the hedges in your local area. Use the species present in mature hedges in your locality as a guide to the new hedge mix, as this will not only help to preserve the character of the area but will ensure that your plants are well suited to the local soils and climate. Always source your hedge plants from a reliable stockist. Native trees and shrubs are the best choices for wildlife, but be aware that many suppliers will stock native trees grown on the continent and shipped over. If possible, source local origin (local provenance) trees. The term local origin means that the trees are grown from seed collected from naturally occurring native trees growing in Northern Ireland. These plants are better adapted to local conditions and the timing of events such as budburst and flowering are more likely to complement our wildlife. Choice of species will also depend on the function of your hedge. For example, a pure hawthorn or hawthorn-blackthorn mix in the ratio 4:1 would be suitable for stock-proofing. If your intention is to create a conservation hedge to attract and sustain wildlife, use a wider selection of native species. A recommended composition would be: hawthorn 50%; blackthorn 15%; hazel 15% and 20% of other species, selected from guelder rose, spindle, dog rose and holly.

4 Include some hedgerow trees: crab apple, oak, ash, tree willows or alder in wetter areas, birch/ rowan in acid uplands. Table: Choosing your hedge plants Species Soil preference Suitability as hedge plant Hawthorn Crataegus monogyna Blackthorn Prunus spinosa Hazel Corylus avellana Holly Ilex aquifolium Gorse Ulex europaeus. Willow Salix sp. Beech* Fagus sylvatica Guelder rose Viburnum opulus All soils but not exposed or elevated sites. Grows on wide range of soil types avoids very acid soil. All free-draining soils, preferring fertile moist alkaline or neutral soils. Wide tolerance except poorly drained soils. Prefers poor dry soils, typically suited to upland and coastal sites. Damp soils, most species withstand seasonal waterlogging. Well drained sites sand and limestone soils. Prefers a wet soil. Dislikes very acid or very dry conditions. Fast growing and hardy, good stock barrier, stands hard cutting. Prone to disease soil may develop thorn sickness. Dense, spiny shrub. Very hardy, and grows quickly after cutting. Suckers readily into adjacent land. Not tolerant of heavy shade. Bushy tree / shrub that branches from the base. Responds well to cutting but can be difficult to establish. Tough and stockproof. Evergreen provides good shelter. Grows well in shady conditions. Slow growing and expensive to buy. Tough and evergreen, good for screening if properly managed. Can become thin at base. Damaged by frost and burns easily. Can be invasive. Rapid growth, offer good shelter and screening. Coppice easily. Poor stock fence. Retains leaves in winter and provides good shelter. Easily trained. Slow growing and poor stock barrier. Low growing, compact shrub. Light-demanding and will not fruit or flower well in shade. Wildlife value Excellent. Flowers attract bees, many insects on leaves. Berries taken by mammals and birds. Good nesting cover. Early flowers provide food for bees and other insects. Good nesting cover. Rich in insects. Nuts are valuable food source for birds and mammals. Holly blue butterfly depends on holly flowers. Berries eaten by song thrush, mistlethrush, fieldfare, redwing, starling and woodpigeon. Good cover for birds, especially linnets and yellowhammers. Attracts insects. Catkins in March/ April are an important food source for butterflies and other insects early in the year. Few associated insects, but provides nuts for birds and mammals, and offers good cover for nesting birds. Blossom attracts insects, and bright red berries are a favourite food for birds.

5 Dog rose Rosa canina Spindle Euonymous europaeus Elder Sambucus nigra Crab apple Malus sylvestris * Non-native species Grows on a wide range of soil types but dislikes very wet soil. Rambling rose, very prickly. Best planted in an established hedge, as it can smother young saplings. Good for filling in large gaps. Roughly 100 insect species associated with this plant. Birds and small mammals eat the autumn crop of rosehips. Prefers lime-rich soils Low growing shrub Birds attracted to the fruit and seeds. Good for insects. Wide tolerance Wide range of soils but prefers neutral. Low growing shrub. Will grow well in coastal and exposed sites. Very invasive and must be cut back regularly to prevent it dominating the hedge. Small growing tree with spiny twigs. Good as a hedgerow tree. Excellent. Dense clusters of black berries attract birds, and elder flowers provide a valuable source of nectar to insects in summer. Excellent. Wide range of insects attracted by pale pink flowers. Fruit taken by mammals and birds e.g. bullfinch. Planting guide Small plants (40-60cm tall) are more cost effective and will establish better than larger specimens. Site preparation will depend on planting method (see below). If notch planting (see diagram opposite) is the chosen method, it is a good idea to reduce competition from grasses and perennial 1. Initial cut weeds. This can be done by mowing and removing any rough grass along the hedge strip during the summer prior to planting, or by applying a non-residual glyphosate herbicide such as Round-up. Cultivation of the soil prior to planting is recommended as it helps break up the turf layer and check the growth of grasses and weeds. It also facilitates planting and creates a good tilth (crumbly texture) to aid plant establishment. 2. Make a T-notch with the spade Depending on the root depth and width of the young trees, planting can be accomplished by notch planting with a spade, or by simply using a crowbar. Alternatively, a trench 50cm wide and 30cm deep can be dug along the line of the new hedge. This has the same benefits as soil cultivation prior to planting.

6 Hedges can be planted in a single row or in double rows. See diagrams below for recommended plant spacing. Single Row 20-30cm Double Row: this method works out at approximately 7 plants per metre 30-45cm 50cm To maintain local style, it is sometimes desirable to create a hedge bank and plant on top of it. In the case of very wet soils, this may already be a requirement. If using bare root trees, the planting season is from the beginning of October to the end of March. Cell-grown trees can be planted at any time of year, providing ground is not frozen or waterlogged. Autumn is considered the best time to plant in free draining ground, spring if the ground is heavy. Plants should be placed into the ground at the same depth as they were in the nursery. This is marked by the root collar, usually identified by a change in colour in the stem just above the root. Ensure the plant is firmed in well. All damaged or dead shoots should be removed at the time of planting. When planting in autumn, hawthorn and blackthorn should be pruned back immediately after they are firmed in. See pruning guide for more information. Replace any hedge plants that fail to establish after the first year. Pruning guide for hawthorn and blackthorn Pruning hawthorn and blackthorn in the first few years after planting will encourage the shrubs to branch more from the base, giving a thicker and more stockproof hedge. Immediately after planting in autumn, prune each plant to about 15cm, or one third its height. Later in the winter, hard pruning could leave the plants susceptible to frost damage. If planting is carried out from mid-november onwards, the first prune is best left until the following autumn. In the second winter, cut back the previous season s growth by about one half In the third winter, trim the laterals and leading shoots to an even shape. First year cut plant to one-third its height First prune cut plant to one third its height Subsequent years trim laterals and leading shoots to an even shape Diagram: pruning method

7 Fencing Fencing may be required to protect your newly planted hedge from damage by farm livestock, rabbits and hares. Tree guards may be adequate protection against rabbits and hares, but a fence will be necessary in the case of grazing livestock. The minimum distance between the hedge and fence is 1m, but a 2m gap is more beneficial to wildlife, allowing for the development of a hedge with a thick, bushy base. Aftercare During the early period of establishment, watch out for signs of drought, and water the hedge if necessary. For the initial 3-4 years, it is important to control competing weeds, either by hand weeding, mulching, or careful application of glyphosate herbicides. Black polythene sheet mulches can be laid prior to planting, and the young saplings slotted into pre-cut slits at the correct spacing. This can then be weighed down with a light covering of gravel. The sheeting must be removed once the plants have become established. Other suitable mulches, laid after planting, include straw, woodchip, rotted manure or even cheap waste materials such as thick plastic sacks, carpet, layers of newspaper or cardboard. If using a glyphosate herbicide as a method of controlling weeds, be very careful not to spray the hedge foliage We hope that this guide will help you when planning and planting a new hedge. Recommended Further Reading: Choosing your garden hedge EHS leaflet, 2004 Field Boundaries 3 Hedges planting and aftercare, DANI leaflet series, 1994, ISBN Habitat Creation and Repair Oliver L. Gilbert and Penny Anderson, Oxford University Press, 1998, ISBN Hedgerows ENFO Briefing sheet 10 Hedges on the farm DOE/ DANI, printed in UK for HMSO / C Hedging a practical handbook Alan Brooks and Elizabeth Agate, 2 nd Edition 1998, ISBN Planting Hedgerows Networks for Nature leaflet, Hedgerow Management series Trees on the farm DOE/ DANI publication