Ecological hedging
Ecological hedging / insect-friendly hedging
1. Definition: what is an insect-friendly hedge?
From the Greek entomo (insect), these are hedges that shelter and support predatory insects (also known as beneficials), which attack pests such as aphids, scale insects and whitefly. The aim is to achieve a natural balance and to reduce the number of chemical treatments while still ensuring good crop protection.
2. Principle: attracting predatory insects with certain plant species:
The idea is to plant species that:
- attract birds (through their fruit)
- attract beneficial insects and pollinators (through their flowers)
- provide shelter for that wildlife in winter (evergreen plants)
- naturally repel pest insects (aromatic plants)
3. Alternative: aromatic plants:
Combining them with aromatic plants makes this biological control more effective
- Garlic (Allium sativum) => keeps aphids away
- Common rue (Ruta graveolens) => keeps aphids away
- Peppermint (Mentha piperita) => keeps aphids away
- Sweet alyssum (Alyssum maritimum - Lobularia maritima) => attracts hoverflies
- Phacelia (Phacelia tanacetifolia Bentham) => attracts hoverflies
- Tansy => repels ants and therefore aphids, and attracts hoverflies
Example of an insect-friendly hedge
Over a run of 18 metres, planted in 2 rows 0.75 metres apart, with plants set 1 metre apart along each row.
- For a "good" hedge, we recommend 1 evergreen shrub for every 2 deciduous ones, always favouring species that are widely represented in your area.
- Avoid multiplying species endlessly, as predators may be common to several species and quickly colonise them. Try to focus on 5-10 species at most, while avoiding a mechanically repeated block of 5 plants.
- Plant species that meet the needs of beneficial insects throughout the season (food, shelter and reserves to see them through winter), alternating species with different structures (evergreen/deciduous) and staggered flowering periods (from January to September). The aim is to bring beneficials onto the crops as early as possible and to keep them as late in the season as possible by offering them shelter and reserves for overwintering.
- Combining "fast" plants such as Ligustrum with "long-lasting" plants such as Ilex, well interspersed, allows the hedge to be formed in 2 years.
- High density closes the hedge up quickly, provided pruning at the end of the first year is not neglected.
- Allow a maximum distance of 50 metres between the insect-friendly hedge and the centre of the plot to be protected.
An ecological hedge provides a habitat for the main beneficial insects.
Cantharis rustica
The larvae feed on snails, which they kill by injecting venom through a bite. The adults eat a mixture of mites, aphids and small insects. It has soft wing cases, barely ridged and covered with hairs. Its thighs are red and its pronotum orange-red with a black spot.
Ladybird
Adult ladybirds and their larvae are great eaters of pest insects (between 10 and 100 aphids a day and 5 to 10 scale insects). Some specialise in aphids, others feed only on scale insects and some prefer mites. As soon as the temperature rises above 15°C in spring, ladybirds become active.
Ladybird larvae
When laying, the female ladybird chooses a leaf infested with aphids and settles there to lay her eggs, fifty to four hundred of them. After three to seven days the eggs hatch and larvae emerge. Ladybird larvae are great eaters of pest insects: extremely voracious, they eat up to 150 aphids a day.
Lacewing
This insect lays several hundred eggs, with two to four generations a year, and is active from April to September. The adults feed on pollen and flower nectar, thereby aiding pollination. Their larvae are predators, eating on average 60 aphids a day, as well as young caterpillars, mites, whitefly, thrips and mealybugs. Active from early spring.
Deraeocoris ruber
Deraeocoris ruber is a predatory insect species of the suborder Heteroptera (true bugs). It can be found on a wide variety of plants. It attacks in particular the larvae of Craesus septentrionalis (the birch and alder sawfly). The adults eat mites and aphids.
Hoverfly
Hoverfly larvae (small flattened maggots) devour aphids. The adults feed only on pollen and nectar. To encourage hoverflies in the garden, it is best to have plenty of flowers in early spring. Smaller than a wasp, with large eyes and short antennae, and able to hover and move sideways. A dipteran with two wings rather than the four of a wasp.
Acer campestre
A small tree with a dense, rounded habit. Widely used in country hedges. Slow growing.
Benefits: Shelter for birds; attracts many beneficial insects
Soil: ordinary
Flowering period:
Foliage: deciduous
Maintenance: tolerates pruning, even hard pruning
- Yellow-green
- green
- shrub
- H:3.00 W:2.50
- -20°C
- full sun
Amelanchier lamarckii
Blazing autumn
Berries much appreciated by birds; the shrub is very well branched, with leaves that are first bronze, then dark green, and finally orange-red in autumn. Hanging clusters of white flowers followed by sweet, juicy, deep purple fruit.
Benefits: Berries much appreciated by birds
Soil: light and moist
Flowering period: April to May
Foliage: deciduous
Maintenance: prune (January-February, December); remove the suckers of stoloniferous species in winter
- white
- bronze-green then red
- shrub
- H:3.00 W:3.00
- -20°C
- full sun to partial shade
Arbutus unedo
Strawberry tree
A tree with glossy, leathery leaves. Peeling brown bark. Small white, sometimes pinkish flowers, producing edible strawberry-like fruit a year later. Flowers and fruit are present at the same time in autumn. Edible and medicinal. Fruit-bearing. Berries much appreciated by birds.
Benefits: Berries much appreciated by birds
Soil: light, dry to moist
Flowering period: September to November
Foliage: evergreen
Maintenance:
- pink-tinged white
- green
- shrub
- H:2.00 W:2.00
- -10°C
- full sun
Buddleja davidii
Butterfly bush
Buddlejas are vigorous and really easy to grow. They produce many panicles of fragrant blue, purple, pink, red or white flowers on which myriads of butterflies feed in summer.
Benefits: Berries much appreciated by birds
Soil: light, dry to moist
Flowering period: August to September
Foliage: deciduous
Maintenance: (March-April) cut the branches back to one quarter of their length
- blue, purple, pink
- grey-green
- shrub
- H:1.5 to 2.5 W:1 to 2
- -20°C
- full sun
Carpinus betulus
Butterfly bush
A tree with oval mid-green leaves, turning orange-yellow in autumn and staying on the branches until late winter. The green male flowers appear in autumn as hanging cylindrical catkins. The female flowers appear in spring from March onwards, insignificant in size, with a three-lobed bract.
Benefits: Shelter + intense insect activity
Soil: ordinary, moist
Flowering period: June to July and October to February
Foliage: deciduous
Maintenance:
- green then orange
- tree
- H:2.50 W:2.50
- -20°C
- full sun to partial shade
CERCIS siliquastrum
Judas tree
The Judas tree is sought after for its superb flowering in April. Before the leaves appear, it is literally covered with thousands of small, unusual flowers.
Benefits: Masses of flowers that attract insects
Soil: dry
Flowering period: April
Foliage: deciduous
Maintenance: Prune after flowering
- mauve, pink, white
- glaucous green
- Tree-like
- H:3.50 W:2.50
- -15°C
- full sun
Cotoneaster lacteus
...
This shrub is compact with a rounded or egg-shaped crown. Oval mid-green leaves, turning orange-yellow in autumn and staying on the branches until late winter. Green female catkins. An ideal shrub for clipped hedges from 1 m to 10 m tall, often with spectacular fruiting that sometimes lasts through part of the winter.
Benefits: Berries much appreciated by birds
Soil: ordinary, moist
Flowering period: June to July and October to February
Foliage: evergreen
Maintenance: pruning after flowering: prune lightly and remove any stems that spoil the plant's shape.
- white
- green then orange
- shrub
- H:2.5 to 4 W:1 to 2
- -20°C
- full sun to partial shade
Convolvulus cneorum
...
A bushy, dense, rounded shrub. From late spring to late summer it bears white flowers with yellow centres, opening from pink buds. Evergreen leaves that are silvery, narrow and silky.
Benefits: Attracts hoverflies
Soil: dry
Flowering period: May to August
Foliage: evergreen
Maintenance:
- white
- silver
- shrub
- H:0.50 W:0.75
- -10°C
- full sun
Cornus alba Aurea
...
This shrub has bright red young shoots in winter, combined with beautifully golden leaves. From late spring to early summer it bears creamy white flowers followed by white fruit.
Benefits: Flowers + food store
Soil: ordinary, moist
Flowering period:
Foliage: deciduous
Maintenance: (February-April) Before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit; prune sparingly.
- creamy white
- golden, with red wood
- shrub
- H:2.50 W:2.50
- -20°C
- full sun
Cornus mas
...
A vigorous shrub with small yellow flowers on bare branches in late winter, before the dark green leaves develop. The fully ripe red fruits are edible and the flowers are rich in nectar.
Benefits: Early flowering, valuable for the first pollinators, and edible fruit (wildlife)
Soil: ordinary, moist
Flowering period: February to March
Foliage: deciduous
Maintenance: prune (February-April) before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous ones. Prune sparingly.
- yellow
- green then purple
- shrub
- H:2.5 to 4 W:1 to 2
- -20°C
- full sun to partial shade
Cornus sanguinea
Common dogwood
A shrub with green leaves turning red in autumn. In early summer, white flowers in flat, dense cymes. The young shoots are a beautiful orange-red in winter. Remarkable bark and finely speckled black fruit.
Benefits: Flowers + food store; attracts beneficial insects
Soil: ordinary, moist
Flowering period: June to July
Foliage: deciduous
Maintenance: pruning (February-April) before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit.
- white
- green then orange
- shrub
- H:1.5 to 2.5 W:2 to 3
- -20°C
- full sun
Corylus avellana
Common hazel
A shrub with supple wood. Broad leaves. Hanging yellow catkins in winter. Hazelnuts on the previous year's shoots.
Benefits: Insect shelter; attracts many beneficial insects
Soil: ordinary
Flowering period: January to March
Foliage: deciduous
Maintenance: pruning (July-August) Prune to keep light coming through the branches by removing water shoots from the centre. Also remove suckers, cutting them off flush with the base before they spread.
- yellow
- green
- shrub
- H:2.5 to 4 W:2 to 3
- -20°C
- full sun
DEUTZIA scabra Pride of Rochester
...
This large-growing Deutzia produces clusters of double flowers, white inside and white tinged with pink outside, with a honey scent.
Benefits: Masses of flowers that attract butterflies
Soil: ordinary, moist
Flowering period: June to July
Foliage: deciduous
Maintenance: prune after flowering: cut back the shoots that have flowered to just above the lower branching point or a bud. Remove one fifth to one quarter of the old stems at the base.
- white and pink
- green
- shrub
- H:2.5 to 4 W:2 to 3
- -20°C
- partial shade
Euonymus europaeus
...
A bushy shrub. In autumn the deciduous mid-green leaves turn red and the red fruits open to reveal their orange seeds. The fruits are toxic to humans. For hedging.
Benefits: Berries much appreciated by birds and caterpillars
Soil: ordinary, moist
Flowering period: April to May and October to December
Foliage: deciduous
Maintenance: pruning (February-April) before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit.
- white
- green then red
- shrub
- H:3.50 W:2.00
- -20°C
- full sun to partial shade
Fagus sylvatica
...
A majestic tree with a rounded crown. Oval leaves with wavy edges, green, turning coppery in autumn. Can be used for hedging. Suitable for bonsai.
Benefits: Shelter for birds
Soil: ordinary
Flowering period: April to May
Foliage: deciduous
Maintenance: prune (February-March) before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit.
- green yellowish
- green
- tree
- H:3.50 W:3.00
- -20°C
- full sun to partial shade
FORSYTHIA intermedia x Lynwood Gold
...
A bushy, vigorous shrub. Oblong, finely toothed leaves. Bright yellow flowers along the branches in late winter. Tall, with large bright yellow flowers and very free-flowering.
Benefits: Masses of flowers that attract insects
Soil: ordinary, moist
Flowering period: February to March
Foliage: deciduous
Maintenance: (April-May) After flowering, cut back the shoots that have flowered to just above the lower branching point or a bud. Remove one fifth to one quarter of the old stems at the base.
- bright yellow
- green
- shrub
- H:2.00 W:2.50
- -20°C
- full sun to partial shade
Hedera helix
Common ivy
This is common ivy, which can cover a wall, act as woodland ground cover or climb up a tree. An excellent source of nectar in autumn (bees ignore the pollen). The honey is pale and powerfully fragrant.
Benefits: Prime shelter for many insects
Soil: ordinary
Flowering period:
Foliage: evergreen
Maintenance: pruning (January-December) prune to keep the plant within its space, and carry out renovation pruning if needed.
- yellow
- green
- shrub
- H:0.25 W:6.00
- -20°C
- full sun to partial shade
Ilex aquifolium Alaska
Holly
The leaves of this female holly are dark green and particularly prickly, and its many berries are bright red. Female shrub.
Benefits: Berries much appreciated by birds
Soil: ordinary, moist
Flowering period:
Foliage: evergreen
Maintenance: prune before growth resumes: cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit. Formative pruning in the first years only. Pinch out shoots in summer. Trim as a hedge in early spring.
- white
- dark green
- shrub
- H:2.00 W:0.80
- -20°C
- full sun to partial shade
Laurus nobilis
Bay laurel
A shrub with highly aromatic, leathery leaves of a glossy dark green. Small star-shaped pale yellow flowers, followed by egg-shaped fruits, green then black. Medicinal, culinary and fragrant.
Benefits: Insect shelter + flowering
Soil: light and moist
Flowering period: April to May
Foliage: evergreen
Maintenance: pruning (February-April, July-August) Before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous ones.
- pale yellow
- dark green
- shrub
- H:2.5 to 4 W:1 to 2
- -20°C
- full sun to partial shade
Ligustrum vulgare Atrovirens
Common privet
The most widely used common privet, as this variety is evergreen and fast growing. Its white flowers are fragrant and its black fruits last a long time.
Benefits: Prime shelter for many insects and birds. Nectar-rich flowers.
Soil: ordinary, moist
Flowering period: June to July
Foliage: evergreen
Maintenance: (February-April, July-September) before growth resumes, cut out diseased and dead wood and crossing branches, keep only the vigorous branches and maintain a good habit.
- white and fragrant
- dark green
- shrub
- H:2.5 to 4 W:1 to 2
- -20°C
- full sun to partial shade
Malus Professor Sprenger
Ornamental crab apple
An upright tree with white flowers, followed by deep red, sometimes yellow-tinged fruits, glossy and persisting after leaf fall. The fruit can be eaten raw as a dessert, cooked or juiced.
Benefits: Berries much appreciated by birds + food store
Soil: ordinary
Flowering period: May, then October to December
Foliage: deciduous
Maintenance: pruning (February-April) Before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit.
- white
- green
- shrub
- H:4.00 W:3.00
- -20°C
- full sun
Mespilus germanica
Medlar
A large, spreading bushy shrub, the medlar is of interest for its white flowers, the autumn colour of its leaves and its curious orange-yellow fruits, which are edible and delicious.
Benefits: Berries much appreciated by birds
Soil: light and moist
Flowering period: May
Foliage: deciduous
Maintenance: No pruning affects its fruiting, nor the size or quality of the fruit. Simply thin the crown by removing a few branches.
- white
- green
- shrub
- H:2.00 W:1.50
- -20°C
- full sun to partial shade
Pachysandra terminalis
...
Pachysandra makes good ground cover for shade, growing fairly slowly. It is of interest for its dark green evergreen foliage. It needs little upkeep.
Benefits: Masses of flowers that attract insects + insect shelter
Soil: ordinary, moist
Flowering period: June
Foliage: evergreen
Maintenance:
- white, in spikes
- green
- shrub
- H:0.20 W:1.00
- -20°C
- partial shade
Rhamnus frangula
Alder buckthorn
A bushy shrub with oval, glossy leaves that turn red in autumn. It produces small green flowers, followed by small fleshy spherical fruits, red, turning black as they ripen.
Benefits: Highly valuable for certain caterpillar species (brimstone butterfly) and for birds
Soil: light and moist
Flowering period: May to June
Foliage: deciduous
Maintenance: pruning (February-April) Before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit.
- green
- dark green
- shrub
- H:5.00 W:5.00
- -20°C
- full sun to partial shade
Salix caprea
Goat willow
Its oblong, slightly wavy leaves have a curved tip and are bright green above and greyish beneath. Grey, silky catkins with yellow anthers appear before the leaves.
Benefits: Pioneer species with valuable early flowering
Soil: ordinary, moist
Flowering period: March to April
Foliage: deciduous
Maintenance: prune (January-March) before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit.
- silky grey and yellow
- green bright
- tree
- H:various W:2.00
- -20°C
- full sun
Sambucus nigra Aurea
Striking contrast
This elder, with its soft golden foliage, is adorned with creamy flowers in late spring. The berries that follow, red then black, form a striking contrast with the pale foliage. The nectar-rich flowers have many medicinal properties. The white, fragrant flowers, gathered in umbels, appear in June and July.
Benefits: Berries much appreciated by birds; attracts hoverflies
Soil: ordinary, moist
Flowering period: June
Foliage: deciduous
Maintenance: prune (February-April, July-August)
- white
- golden
- shrub
- H:2.5 to 4 W:2 to 3
- -20°C
- full sun to partial shade
Spiraea x billardii
...
A shrub with dense foliage. In summer it bears dense panicles of five-petalled purple-pink flowers. Oval to lance-shaped, toothed, dark green leaves.
Benefits: Flowers + food store
Soil: ordinary
Flowering period: July-August
Foliage: deciduous
Maintenance: cut all the branches back to one quarter of their length
- pink purple
- green
- shrub
- H:2.00 W:2.00
- -20°C
- full sun to partial shade
Sorbus aucuparia
Rowan
A tree with leaves made up of dark green leaflets, turning yellow or red in autumn. White flowers in corymbs, followed by orange-red fruit in autumn that lasts a long time.
Benefits: A plant much appreciated by birds thanks to its long-lasting fruit
Soil: light and moist
Flowering period: April
Foliage: deciduous
Maintenance: (February-April) before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous branches and maintain a good habit.
- white
- green, yellow, red
- tree
- H:4 to 6 W:3 to 5
- -20°C
- full sun to partial shade
Syringa vulgaris
Lilac
This is the classic lilac that fills the air with scent in spring. It is said that once it flowers, there will be no more frost that season.
Benefits: Flowers
Soil: ordinary, moist
Flowering period: April
Foliage: deciduous
Maintenance: (June-July) after flowering, remove the spent flower heads, dead wood and any dying or badly shaped branches. Hard pruning can be carried out occasionally, but it noticeably reduces flowering the following year.
- 4 colours
- green
- shrub
- H:3.50 W:2.50
- -20°C
- full sun
Viburnum lantana
Wayfaring tree
A species that accepts almost any growing conditions. A shrub with grey-green leaves and rounded cymes of white flowers with prominent yellow stamens, followed by clusters of bright red fruits, later black.
Benefits: Flowers + food store
Soil: ordinary, moist
Flowering period: May to September
Foliage: deciduous
Maintenance: pruning (February-April, July-August) Deciduous: after flowering, prune lightly and remove any stems that spoil the plant's shape.
- white
- grey-green then red
- shrub
- H:2.50 W:2.00
- -20°C
- full sun to partial shade
Viburnum opulus
Guelder rose
A vigorous, bushy shrub with lobed leaves, green turning red in autumn. Flat cymes of white flowers, followed by large globular, glossy red fruits in May and June.
Benefits: Flowers + food store
Soil: ordinary, moist
Flowering period: May-June, then September-October
Foliage: deciduous
Maintenance: pruning (February-April, July-August) Deciduous: after flowering, prune lightly and remove any stems that spoil the plant's shape.
- white
- green then red
- shrub
- H:3.00 W:3.00
- -20°C
- full sun to partial shade
Viburnum Tinus Lisarose 'Loren'
Ball of flowers
A unique variety thanks to its long, abundant flowering, its glossy leaves and its bright red buds. The white flowers gradually turn pink towards autumn.
Benefits: Prime shelter for many insects and birds
Soil: ordinary
Flowering period: August to April
Foliage: evergreen
Maintenance: prune (February-April, July-August) Evergreens: before growth resumes, cut out diseased or dead wood and crossing branches so as to keep only the vigorous ones.
- pink-tinged white
- glossy green
- shrubby
- H:2 to 3 W:2.00
- -15°C
- full sun to partial shade
Vinca minor
...
A prostrate plant forming wide carpets of small, glossy dark green leaves covered with small purple flowers.
Benefits: Masses of flowers that attract insects + insect shelter
Soil: dry to ordinary
Flowering period: May to September
Foliage: evergreen
Maintenance:
- purple
- dark green
- shrub
- H:0.15 W:2.00
- -20°C
- full sun to partial shade
Weigelia florida Bristol Ruby
...
An upright, vigorous shrub forming a compact clump. Oval, dark green leaves. In May and June, very deep red buds open into deep red bell-shaped flowers.
Benefits: Masses of flowers that attract insects
Soil: ordinary, moist
Flowering period: May to June
Foliage: deciduous
Maintenance: pruning (August-September) After flowering, cut back the shoots that have flowered to just above the lower branching point or a bud. Remove one fifth to one quarter of the old stems at the base.
- red dark
- green
- shrub
- H:1.5 to 2.5 W:1 to 2
- -20°C
- full sun to partial shade
