- Fast growing, small to medium sized light demanding tree. The young leaves are sticky, hence the specific name. Readily available, relatively cheap and reliable. Enriches the soil with nitrogen. Same family as the birch (Betulaceae) and, like birch, the alder seldom sets seed before the age of 20. Alder attracts a large number of insects and is host to many species of lichen. Goldfinches are attracted to the cones in winter.
- Flourishes in moist situations but will grow almost anywhere. Found growing naturally by watercourses, marshy ground and on hillsides up to 500m, particularly in the north and west where the soil is wet and the rainfall high. In dry, sandy ground it seldom grows into more than a bush. Alder produces suckers.
- Valuable pioneer and nurse species. Most effective planted in single species clumps of 5-10 trees.
- Good for stabilising river banks - establishing initial growth on poor acid ground and contributing to screen planting - it has a dense deciduous form and retains its leaves well into the autumn.
- Can be prone to main-stem die-back in drier soil conditions.
- Large tree with life potential of 300 years. Nutrient and light demanding preferring moist, neutral, rich soil.
- Tolerates coastal conditions.
- Has invasive shallow root system.
- Buds burst late in spring and leaves fall early in autumn.
- Becomes susceptible to ill health in shade.
- Widespread at low elevations associated with oak, birch, elm, hazel, privet, willow and aspen.
- Allow plenty of room for the tree to develop its full potential and accommodate its shallow invasive roots.
- Good tree for hedges and mixed woodlands but also as a single specimen in the countryside - has a fine elegant, upright structural form known as 'Venus of the woods'.
- Not a good tree for the first line of defence in a shelter-belt.
- Young trees need some form of protection to establish rapidly, so consider tree shelters for small specimens.
- Seeds encourage birds (bullfinches) and small mammals.
- Excellent tree to encourage ivy growth for companionship.
- Medium sized tree - relatively slow growing and short lived (100 years). Grows well and is wind firm on a wide range of soils on both coastal and exposed upland sites - one of the last trees to break bud (May/June) - leaves tremble distinctively - clear yellow autumn colour.
- Scotland's only native poplar, distributed widely in the north and west growing in scattered clumps and in association with ash, oak and birch and on rock crags.
- Difficult to propagate, so relatively expensive.
- Good pioneer for damp harsh conditions - regenerates readily by suckering, so good for semi-natural woodlands and where grazing damage is likely.
- Light demanding, so best planted in open or woodland edge. Does not grow well on newly consolidated slopes, fly ash or shales.
- A good tree for supporting a wide range of insect species (90).
- Aspen rarely sets viable seed in Scotland so the origin of the trees needs to be checked carefully to ascertain they are of Scottish origin or provenance.
- Large tree able to live for 300 years. It is gregarious in habit, growing in small groups or forming large woodlands - dislikes acid and wet soils - will grow in poor soil but slowly - casts deeper shade than any other native broad-leaved tree. It can out-compete most other species because of its shallow root system, the shade it casts and its sheer vitality. Although it prevents herb growth beneath the canopy, the leaf mould is rich in plant saprophytes and fungi that do not require light. The seed is a rich source of oils for birds - finches, pheasants and wood pigeons.
- Makes a valuable contribution to Scottish landscape character - planted as shelter belts and as notable roadside hedges, but it is unlikely to have ever been native in Scotland.
- Beech make a striking statement grown in a clump.
- They also make interesting companions in their early life with hemlock (Tsuga heterophylla) - the graceful evergreen form of the conifer contrasting with the russet brown leaves of the beech in winter.
- Because of their strong surface root system they can grow on steep slopes and stabilise cutting or embankment slopes.
- The leaf mould is a rich and natural source of mycorrhizal fungi that can be used to inoculate seed-bed growing medium
( Betula pendula)
( Betula pubescens)
- There are 3 species of native birch - Silver, Downy and Dwarf. The dwarf species is confined to mountainous and bog regions and so is not included in this list because they are not commonly used in road schemes. Birch is one of the most elegant of our native trees - Coleridge referred to the silver birch as 'lady of the woods'. It is also one of the hardiest and most versatile and will grow in everything from wet to relatively dry conditions. It is a small tree (15m), light demanding and short lived- only living for 50-80 years. The main differences between silver and downy are:
- The twigs of silver are smooth and the trunk white - the downy twigs are covered with down and the branches not so white.
- The silver prefers dry ground and the downy damp to wet ground. Both species support a vast variety of insect species (200) and lichens (100).
- Birch is perhaps the most versatile of all Scottish native trees. It makes a magnificent spectacle en-masse as a single species woodland - changing colour in the winter sunshine from purple to almost orange and russet. It is equally spectacular as a single specimen or even better in a small clump, in the open countryside or built environment.
- Birch is a valuable tree for wildlife - it casts light shade and so allows ground flora to develop - the seeds attract birds, redpolls especially, and red squirrels - the leaves support over a hundred species of insects.
- Bare root birch can be difficult to transplant successfully. Container grown plants, either singly in cells or as a mixed species clump with pine or rowan, improve transplanting performance and the latter can add a new dimension to landscape planting design. Birch are very hardy, if healthy, and will grow at a very fast rate once established. (They have exceptionally been measured with growth rates of 2.6 metres per year in height.)
( Malus sylvestris)
- Small, light demanding tree preferring moist well-drained soils, but will also grow well in heavy soils. It flowers early in the spring and produces masses of 'crabs' that provide food for birds well into the winter. Crab seed is unusual in that it produces plants true to the parent plant - most other species produce variable characteristics in their offspring.
- Occurs naturally in old woodland throughout the lowlands - not common in the north-east. Planted widely in the countryside near housing.
- Crab apple is an underused small tree which could add greatly to the amenity and wildlife value of roadside planting especially if planted as an edge species that is seen from the road.
- Do not plant on poor, dry soils for in these conditions they become prone to pest and disease.
( Ulmus glabra)
- Scotland's only native elm arriving before the Romans introduced the common elm to England. The wych elm is not as tall as the common elm but is more robust - both live for up to 500 years. Wych elm dislikes atmospheric pollution, and has seeds that form within a round flat membrane that blow in the wind like confetti.
- Unlike its English counterpart it has not found it necessary to produce suckers to secure succession.
- Wych elm is more commonly found in the drier east of the country. It will form a large tree in more sheltered areas but remain a tall shrub in extreme exposure. Wych elm is often not planted because of its susceptibility to Dutch elm disease. It is worth planting in the more exposed areas of the north-east where the insects that carry the disease find life difficult - in any case the wych is not so susceptible to the disease as the Common elm and tends to be attacked once the stems are quite large. It stands repeated coppicing and can be cut back hard when the disease attacks to promote new growth.
- It is also worth planting where it is beneficial to attract early insects and provide food for red squirrels.
- Do not plant in very dry soil.
( Acer campestre)
- Field maple is not common in Scotland, occurring mostly as a shrub in hedges rather than a small tree. Field maple is also referred to as the common English or small leafed maple. It is the only maple native to Britain. There are suspicions that it naturalised in Scotland after becoming firstly established in England.
- The bark of old trees becomes corky and the leaves, characteristic of other maples, turn bright yellow. The field maple can be an impressive small tree in the right conditions.
- Will only need to be used occasionally in Scotland, either where existing field maple currently grow or in the built environment for special effect.
( Prunus avium)
- Gean is a fast growing tree that can make an early impact on a planting scheme.
- It has a very invasive and shallow rooting system.
- The blossom is consistently good, producing fruit for birds.
- The fallen leaves in autumn have a distinctive and pleasing scent of marzipan
- Gean should not be planted where it can damage underground services or foundations.
- It multiplies itself time and time again by producing root suckers after only a few years and is consequently excellent value for money and ideal for semi-natural woodland. In the long term it can become over dominant.
- A variety of wild cherry is grown in Eastern Europe from the stones rejected during the manufacture of jam. Trees from this source have been inadvertently planted in Scotland in the past - fortunately they are prone to terminal canker in their seventh or eighth year. Care is required to ensure that no more such trees are planted in the countryside.
( Prunus padus)
- A relatively small tree growing up to 15m. It is notable for its creamy white long spikes of fragrant flowers in late May. The flowers are followed by clusters of small black shiny berries in August.
- Grows naturally in large clumps predominantly in Perthshire, Speyside and the Borders.
- Best planted in clumps in the countryside but can grow equally successfully trained as a single stemmed standard for more formal use.
- Will grow well in damp ground.
- A useful tree to add distinction to autumn colour; the leaves turn an interesting yellow and pink and sometimes red.
( Ilex aquifolium)
- Holly is a small hardy tree growing up to 15 metres in ideal conditions. It is one of the few Scottish native evergreen trees and is notable for its prickly leaves and red berries. The species is dioecious, (male and female flowers grow on separate trees) so at planting time there is no telling if it is female and will produce berries. The berries are important winter food for thrushes and the dense structure of the form provides valuable roosting accommodation. Despite its tough leaves it is particularly prone to rabbit damage.
- Holly does not grow well in poorly drained soil. It is widespread throughout the country but dislikes exposure near the coast. It is very shade tolerant and so is normally found growing as an understorey tree or with companion species.
- Holly has 'soft' roots and doesn't transplant readily and so needs to be container grown. Ideally the root growth needs to be one year ahead of the shoot. This can be simulated by specifying that the plants shall be pruned before planting - e.g. '60-90 cm, container grown plants cut back to 20cm immediately prior to despatch from the nursery'.
- Successful establishment may also be improved if they are protected by shrub shelters or grown and planted as a multi-species unit with oak, birch or rowan.
- Tree shelters encourage rapid establishment of holly in mixed hedges - the etiolated plants are supported initially by the other hedge plants. It makes a particularly good and impenetrable hedge plant in its own right.
( Carpinus betulus)
- Hornbeam is not a large tree (15-20m), similar in appearance to beech but with a character of its own - the trunk is short and the crown massive and irregular - the mature trunk is often distinctive in that it is elliptical in section and becomes fluted as if formed from fused cylinders. It has further distinctive characteristics in that the clusters of fruit hang in tassels with curious leaf-like appendages like triple winged sycamore 'keys'. They remain on the tree well into the winter giving the tree a light russet brown haze.
- Hornbeam is not a common tree in Scotland, mostly distributed erratically throughout southern Scotland. Historically planted to provide fine-grained, very hard wood to make tool handles, carts, chairs, coppice poles and barrel hoops.
- Hornbeam is a tree to use with care. It can add a subtle yet distinctive character to the lowland landscape as an alternative to beech, especially where the soil is too heavy for successful growth of beech.
- It can also make a good hedge as it branches profusely when trimmed and the leaves turn from yellow to orange to a rich russet.
(Q uercus robur)
( Quercus petraea)
- There are two native oaks - Common and Sessile. They have also hybridised widely. They are long-lived wind firm trees surviving up to 1000 years. They vie with the ash for lateness of bud burst (May) but unlike ash retain their leaves till November.
- Both species produce acorns relished by squirrels, jays and other small mammals. After birch the oak is the most valuable of our native trees for wildlife - insects, birds (tits in particularly are attracted to the caterpillars), fungi, lichen and dead wood. The purple hairstreak butterfly is dependent on oak for its survival.
- The Common oak grows more commonly in the south and east preferring clays and damp lowlands. Older specimens are more remarkable for their girth and twisted, knarled, zigzagging elbows and branches than their height.
- The Sessile oak grows predominantly in the north and west preferring more acidic soil. The remaining remnants of the original Atlantic Oak Forests in Argyle and the Western Highlands are important habitats for lichens, liverworts and mosses. Q.petraea is more shade tolerant than Q.robur and also hardier.
- The two species need to be matched carefully to the ground conditions. In appropriate ground conditions and especially in a mixed woodland situation, they will grow surprisingly quickly in their early years.
- Both species make good companion units with holly, honeysuckle and ivy.
- Before planting to form avenues or as individual specimens, consideration should be given to the time taken to develop into mature trees. Often design aspirations are unrealistic.
- Consideration should be given to insect and butterfly Species Action Plans when planting oak woodland. Advice should be sought from the Local Biodiversity Action Group.
( Sorbus aucuparia)
- A small tree partially shade-tolerant. Grows in all soils except heavy clay and calcareous soils. Few native trees can match its flowering, fruiting and autumn colour. Cheap tree to produce and as the roots are resistant to desiccation it transplants readily.
- Widespread through Scotland up to 1000m altitude. Grows naturally in pine, oak and birch woods, as clumps or in association with rural dwellings in the Highlands. The latter planted to ward off evil spirits.
- Reliable and resilient, rowan will grow and looks right almost anywhere.
- It produces the best autumn colour in the colder acidic soils in the Highland regions. Makes a splendid colour companion for birch and pine.
- Suitable for confined spaces, poor soils, rock outcrops, highland burn sides and reclaimed ground. Being partially shade-tolerant rowan makes a good woodland edge species and can grow under a birch canopy.
- Mixes well with birch, alder, holly, wild cherry and goat willow.
- Care is required to ensure that this small tree is in scale with the surroundings, especially in the Lowlands. Ironically, in isolation in the Highlands, it is more likely to be in character.
( Pinus sylvestris)
- Scots pine is the most important British coniferous tree. A large long-lived tree - growing up to 45m and living up to 450 years. Scots pine has a strong and extensive root system, prefers light sandy dry soil and is able to grow in infertile ground, is light demanding, drought resistant and dislikes salt spray. Pine woodlands support a rich assortment of wildlife peculiar to Scotland - notably capercaillie, blackcock and red deer. Coal tits, goldcrests and crossbills all feed on or around Scots pine.
- Its natural range is the central and western highlands, but is now common throughout Scotland, planted extensively as shelter belts in Fife, the Southern Uplands and in the north-east. Trees growing in various genuinely native pinewoods have evolved into many distinctive forms. These woodlands have been codified and listed in a Caledonian Pinewood Inventory.
- A useful tree for all-round value - function, amenity and wildlife. When mature, its character in the countryside epitomises all that is Scottish. When used to restore the ancient Caledonian pine-woods it makes a valuable contribution to Scotland's natural heritage. It looks most impressive when planted in clumps on mounds and crags as it grows naturally. As a functional tree it is equally useful as a nurse species.
- The strong root system prevents erosion in poor soils as it spreads widely searching for nutrients.
- Scots pine forms a good relationship with birch and rowan and for use as a wind-break with beech and sycamore.
- It needs recently disturbed ground to colonise naturally.
- Grows well when planted as a companion plant with birch. Whilst it improves the transplanting performance of the birch.
( Sorbus intermedia)
- The white tree, ('beam' being Saxon for tree) grows into a small sturdy tree - usually as a woodland edge tree or in hedge lines. The lower surface of the leaves is coated by a tough white felt-like material enabling it to withstand exposure and atmospheric pollution.
- In Scotland it is found predominantly in the north and east.
- Useful for seaside and shelterbelt planting and for planting in and around urban areas.
- It has a tendency to be top-heavy and infirm if not associated with other species.
- Whitebeam is one of the few native species that grows well in exposed districts along the east coast together with its non-native companion sycamore.
( Salix sp.)
- Species of willow are numerous and various. They vary in form from tall and spreading trees to dwarf shrubs. To compound the difficulties of identification they have hybridised prolifically. The bark of most mature willows is deeply furrowed and the branches are long, slender and pliant - hence the derivation of the common name 'willing'. Willow was also the original source of asprin.
- All willows prefer damp wet sites - (Salix from the Celtic sal, near, lis, water) dislike atmospheric pollution and are supreme for supporting native insects.
- All willows support a wealth of insect life. Insects, being low in the food chain, ultimately support many other species - birds, bats and so on.
- Willow is useful for bioengineering work and can be used to take up toxic chemicals from soils (bioremediation), living willow walls and sculptures. It will grow readily from un-rooted cuttings in damp soils. Willow is currently being tested widely for use in biomass power generation schemes.
( Salix fragilis)
- A large tree. The twigs are fragile at the joints.
- Develops decay and holes used by birds for shelter and nesting.
- Crack willow is prone to shedding large boughs and so should not be planted close to roads.
- A good choice for planting near ponds.
( Salix alba)
- A large tree. The leaves are white and silky on both surfaces.
Goat (Sallow or pussy willow)
(S alix caprea)
- Large bush and small tree - common in woods and hedgerows - will grow in quite dry soils - particularly conspicuous in early spring are the yellow male catkins and the silver female catkins commonly called 'pussies'.
- A good willow for dry sites. A good large shrub to include in rapid response planting, to provide early colour and flowers for insects. A useful pioneer shrub for contaminated ground.
( Salix cinerea)
- A shrub with a low dense structure. Will not grow on dry sites - catkins abundant and conspicuous.
- Useful for wet sites and where bees are to be encouraged.
( Salix aurita)
- A small shrub that prefers acid soils, bogs and upland sites - produces a wealth of pollen and nectar beloved by bees.
- Can survive very wet acidic sites.
( Salix triandra)
- A large shrub or small tree with flaky bark and glossy green leaves with a glaucous tinge beneath - leaves and male catkins fragrant and almost mimosa-like.
- Will not thrive on sandy soils - must have heavy ground
( Salix pentandra)
- A large shrub or small tree - prefers heavy ground
- Will grow on sites that are occasionally flooded.
( Salix purpurea)
- A low shrub with fine twigs - leaves blue/green above, paler below.
( Salix viminalis)
- Medium sized shrub - stems long and straight used for willow walls and working into baskets.
- Ideal for planting at the waters edge.
( Taxus baccata)
- Yew is a primitive native evergreen conifer that can outlive all other native species in Scotland. Many old trees in churchyards are over 1000 years old. Each tree is either male or female. The male grows flowers on the underside of the shoots that produce clouds of pollen in February. Because they are pollinated this way the female flowers are green and inconspicuous. Young trees grow more quickly than sometimes thought, up to 30cm a year. In later life growth declines. Yew grows well in a wide range of well-drained soils. It is shade tolerant and the leaves are poisonous to livestock.
- Yew is a discrete conifer, widespread throughout the lowlands, growing naturally in the shade of predominantly deciduous woodland.
- Yew is one of our few native evergreens and is not used as much as it might because of its reputation for slow growth. Like holly it needs shelter to establish quickly and performs well planted as a companion species with ash, oak or buckthorn.
- Because the male and female flowers are borne on different trees, yew should be planted in clumps to increase the chance of different genders growing close to each other and so increase the chance of fruit forming.
- It has been discovered recently that yew foliage contains natural ingredients that are of value to the pharmaceutical industry. This is an additional consideration for their use, especially as they grow slowly and may be in greater demand in the future.
( Prunus spinosa)
- The sloe or blackthorn forms a large prickly bush with black bark - hence its common name. The white flowers are one of the earliest to appear in spring - March - before the shrubs' leaves. They are able to do so because they are formed in the previous autumn. Large, fleshy, black fruit, often with a bloom, follow and remain for most of the winter. They do so because they only become sweet when fully ripe some months later.
- Grows naturally in hedgerows, woodland edges and as scattered patches in the open on hill-sides. Particularly good seed is produced in the glens of western Perth and Kinross. It prefers to be in the open and dislikes wet ground.
- Blackthorn is one of our first shrubs to bloom. Clouds of white blossom on black branches grow in March helping to lift the visual depression of the long winter months.
- It is a useful shrub for windswept and coastal locations.
- It forms a dense thorny structure and so makes an effective barrier or hedge. The prickles spear litter and so planting them in litter prone areas such as slip roads or lay-bys should be avoided.
- Blackthorn produces suckers and so is good value for money in semi-natural self- sustaining woodland.