Why plant a native hedge?
British natives are highly desirable for wildlife because our native plants and wildlife have evolved side by side over millennia and for that reason native creatures show a preference for them.
The oak is the most attractive of all and The Woodland Trust produce a list (shown below) to show the difference between natives and non-natives. Many of us do not have room for a mighty oak, but we can plant a native hedge along our boundary.
Native plants provide important refuges for birds, butterflies, moths and small mammals, and they flower and fruit at the correct times. So planting a native specimen or a native hedge is one of the best things you can do to increase biodiversity in your garden.
Native plants attract more insects and that in turn produces greater diversity. The table below shows the enormous difference between Alien and Native Species when it comes to attracting insect species (from www.countrysideinfo.co.uk).
Oak (pedunculate and sessile) - 284
Willow - 266
Birch (silver and downy) - 229
Hawthorn - 149
Blackthorn - 109
Poplar - 97
Crab Apple - 93
Alder - 90
Elm - 82
Hazel - 73
Beech - 64
Ash - 41
Lime - 37
Hornbeam - 31
Rowan - 28
Field Maple - 26
Yew - 4
Spruce - 37
Larch - 17
Fir - 16
Sycamore - 15
Sweet Chestnut - 5
Horse Chestnut - 4
Walnut - 4
Holm Oak - 2
Plane - 1
Rhododendron - 0
Why is it a good thing to attract insects into a garden?
Insects are one of the lower orders of life and these small creatures attract and sustain predatory insects and birds among others. Just those three components (insect prey, insect predators and birds) will build a healthy ecosystem and ensure a natural balance within your garden.
This natural system of pest control is very important, particularly now that chemical use is restricted following the EU Pesticides Review of 2002. Fewer chemicals are available to the gardener now and the process in ongoing - so there will be fewer in the future.
Also many of us growing edible food do not want to spray our food crops due to concerns about our health and where the residues may end up. So we have to build up healthy ecosystems within our gardens.
Will these insects spread through my garden?
No, herbivores (or plant eaters) are fussy feeders. The aphids in my garden for instance happily colonise our native Knautia arvensis (field scabious) but not the alien Scabiosa caucasica - even when the stems are completely intertwined.
This was confirmed by an article in British Wildlife (Oct 2008) by Richard M. Smith and David B. Roy who are relaunching The Database of British Insects and their Foodplants (www.brc.ac.uk/DBIF). Their fascinating article explained that 76% of herbivores rely on one plant family. Even one catholic feeder (the green peach aphid, or Myzus persicae), has only been found on 1% of plant species - some 40 families.
The smaller the herbivore, the fussier they tend to be. So the small insects on your hawthorn are likely to stay there. Don’t spray your hedge - the insect life is likely to be specific to it - leave well alone!
Buying your native hedge
It’s important to try to plant hedging whips raised from British ecotypes if possible.
These flower and come into leaf at the correct time. However, the market tends to be flooded with hedging whips grown in eastern Europe and this can cause problems. Blackthorn whips grown in eastern Europe, for instance, tend to flower earlier than our native blackthorn and often the bees are still hibernating. Ask your supplier for information.
Supplier: Buckingham Nurseries - www.hedging.co.uk
The ideal native hedge
Hawthorn (Quickthorn) (Crataegus monogyna)
Fast growing, very thorny deciduous plant tolerant of wet soils. Dark, glossy, green leaves, clusters of prominent scented white flowers in May followed by plentiful red haws in autumn. Very hardy and useful in coastal or exposed positions.
Blackthorn or Sloe (Prunus spinosa)
Dense, prickly deciduous plant with new shoots finely downy becoming smooth by winter, purple in sun or green in shade. Masses of snow-white flowers appear in March before the leaves, and these are followed by sloes which turn from purple to black in autumn. Any soil, but will thrive on quite poor soil.
Alder Buckthorn (Rhamnus frangula)
A large deciduous shrub with glossy, dark-green leaves which turn red in autumn. Red fruits turn black in autumn. Any soil but likes marshy ground.
Guelder rose (Viburnum opulus)
Vigorous deciduous shrub with flat heads of heavily-scented white flowers in May and June, followed by masses of bunches of translucent bright-red berries in autumn. Turns brilliant red in autumn. Any good moist soil but will thrive in wet or boggy situations.
Field maple (Acer campestre)
Fast-growing deciduous plant with greenish-yellow flowers in spring followed by winged seeds in autumn. Makes an excellent dense hedge and tuns butter yellow in autumn. Well drained, but moist soil.
Dogwood (Cornus sanguinea)
Deciduous shrub with green stems flushed in red. Rich damson-red autumn colouring. Any soil, very chalk tolerant and thrives in a very damp positions.
Spindle (Euonymus europaeus)
Green-stemmed deciduous shrub with inconspicuous flowers in May. Good autumn colour and the red and orange spindles attract birds - particularly robins. Spindle is a host plant for beet and bean aphids - so this is one you may want to avoid. Anyordinary soil, sun or partial shade.
Dogrose (Rosa canina)
Arching branches bearing white to pale-pink single flowers in June followed by glossy red hips in autumn. Loved by birds in winter.
Hazel (Corylus avellana)
Deciduous shrub with large mid-green leaves that appear with the bluebells. Long yellow catkins in early spring are followed by edible nuts in autumn. Cut in winter for stakes and poles.
Euonymus europaeus 'Red Cascade' AGM
The widely available 'Red Cascade' is the most spectacular form of our native spindle. The leaves colour up to lipstick-red by early September, long before most shrubs and trees, and all deciduous euonymus provide the same vibrant early autumn colour.
By October, the leaves of 'Red Cascade' are already falling to reveal hundreds of orange-pipped fruits on a small, twiggy tree that reaches roughly nine to ten feet in height (3m). The sheer weight of the fruit makes the branches droop. The day-glo fruits do not last long however. They are highly popular with birds, especially robins. A note of caution though: all deciduous euonymus provide a refuge for black bean aphids over winter.
When to plant a native hedge
October and November are excellent times to buy and plant the bare-root whips needed to produce a native hedge.
Planting a native hedge
1. Prepare the soil well before planting - preferably in the autumn. Dig a trench 45 cm (18 in) wide and 30 cm (1 ft) deep along the length of the proposed hedge. Improve the ground if you can by adding generous amounts of garden compost or well-rotted manure. If your soil is poorly drained, add sharp sand or coarse grit.
2. Buy bare-root whips as these will form a dense and bushy hedge without any gaps at the bottom. If you want a thicker hedge plant a double row about 60 cm apart.
3. When the plants arrive, unwrap them and soak them for up to two hours in water.
4. Your whips may arrive when the ground is frozen or waterlogged so prepare a 'back up' trench about 50 cm deep in a sheltered place. Cover the trench with old carpet or polythene to keep the ground frost-free.
5. Once planted, mulch well with at least 5-10 cm (2-4 in) bark chips or other mulching material after planting. This will suppress weed growth and retain moisture.
6. Keep the young hedge well watered during its first growing season. In windy sites you may need to use windbreak netting.
Flower and fruit from native hedges
Many native hedges produce flowers and these, in turn, produce edible fruits or seeds. The flowers sustain bees and other pollinating insects and the fruits (or seeds) sustain bird life. The structure of the hedge also provides important nesting sites for many birds including blackbird, robin, wren and thrush.
When fledglings are in the nest, the parent birds will collect enormous numbers of small insects - even of they are principally seed eating once mature. The average blue tit brood of seven will consume 10,000 invertebrates before leaving the nest. Blue tits always seem to time one brood to coincide with the apple blossom and they will collect pests from fruit trees for a three-to-four week period. Thrushes are very efficient snail collectors.
The hedge bottom
This should be left undisturbed, particularly in winter, because the leaf litter will shelter amphibians, spiders, beetles, small mammals and insects. You may well have hibernating toads, hedgehogs and voles asleep under your hedge.Leave well alone. Planting primroses, dead nettle and pulmonarias will provide early flowers for bees.
When to trim a native hedge
The best time to cut a native hedge is late winter. By then, any fruit should have been eaten, but the nesting season hasn’t begun. The best shape is an A - with the widest part of the hedge being at the base - rather than straight up and down. This shape provides more shelter.