Hedgerow aspect

The directional aspect when planting a hedgerow has the potential to exert an influence on fruit set of hedgerow plants, since insect activity can increase with light intensity, solar radiation levels and temperature. Plant physiology itself may also affect fruit setting as plant require carbohydrate, which is primarily produced by photosynthesis in the adjacent spur and leaves. Without sunlight and radiation, which would be restricted if planted in a shady area, shading has been shown to reduce the fruit yields of some orchard crops by increasing fruit abscission. Pollinator activity has been found to increase with increasing temperature, light intensity and radiation. You can see for your selves on a hot sunny day summer the activity of many flying insects/pollinators as opposed to a grey dull summers day. Obviously the insects are only busy around a certain clump of flowers if there is nectar or pollen to be gained from a visit. It simply is not worth them wasting their time if they visit and the visit is fruitless! The plant has to offer a reward, which itself is related to environmental variables such as temperature and relative humidity. Planting hedges and berry bearing plants along a south and west facing aspect, (a warm hedge), as opposed to a north or east facing aspect, (a cool hedge), could be more rewarding for pollinating insects and more rewarding as regarding fruit/berries for birds. As shade affect light levels,this affects berry production. Planting in masses and not isolated trees and shrubs separated by long distances can negatively affect pollination by bees. Quite simply, an isolated tree/shrub may just be too far, requiring a bee to expend too much energy for little reward.

 

Management or in this case, mismanagement has a huge effect on food availability for birds. These hedgerow plants may well have been pollinated by bees, but what good are they now?

 

Our native wild bees are quietly and efficiently pollinating garden and wild flowers, fruit, vegetables, as well as the wild fruits and berries in our hedgerows and trees, providing vital food resources for birds and other wildlife, work undertaken in the main unnoticed. For example, blackthorn sloes, are fed upon by robins, blackbirds, redwings, song thrushes, fieldfares, mistle thrushes, starlings, magpies and crows. They are pollinated by bumblebees, solitary bees and honey bees. It is known that bumblebees can forage early in the morning and at cooler temperatures than honey bees. Blackthorns tend to flower early in the year. I have seen them flower in February where I live and have seen bumblebee queens forage on them. This may be too early for many honeybees, finding it too cold to forage, staying in their hives to keep warm and feed on their honey store. Whereas bumblebees will forage as they have no stores of honey and need to replenish their fat reserves after hibernation. It is likely that bumblebees may well pollinate more blackthorn flowers than honey or solitary bees.

Berries eaten by birds

Plant	Pollinated by	Berries eaten by
Blackthorn	Bumblebees, solitary bees, honey bees, flies, butterflies, beetles	Robins, blackbirds, fieldfares, redwings, mistle and song thrushes, starlings, magpies, crows and sloe gin!!
Bramble	Bumblebees, solitary bees, honey bees, flies, butterflies, beetles	Robins, blackbirds, song thrushes, garden warblers, blackcaps, lesser and common whitethroats, blue tits, greenfinches, bullfinches, moorhens, starlings, and us!
Dog Rose	Bumblebees, solitary bees, honey bees, flies,  beetles	Robins, blackbirds, song and mistle thrushes,  fieldfares, redwings, blackcaps, blue tits, greenfinches, woodpigeons
Hawthorn	Bumblebees, solitary bees, honey bees, flies,  beetles	Robins, blackbirds, song and mistle thrushes,  fieldfares, redwings, blackcaps, blue tits, starlings, woodpigeons, magpies, crows
Honeysucklespp.	Bumblebees, solitary bees, honey bees, flies, butterflies, moths, beetles, wasps	Robin, blackbird, song thrush, starling, blackcap, lesser whitethroat, bullfinch, blue tit, marsh tit
Ivy	Bumblebees, honey bees, wasps*and flies	Robins, blackbirds, song and mistle thrushes,  fieldfares, redwings, blackcaps, greenfinches, starlings, woodpigeons

 

Without bees, very few berries would be produced for birds and mammals.

Although some of the above species are true berry eaters, such as blackbirds, which digest the fruit pulp and disperse the seeds, others such as greenfinches are ‘seed predators’. I have seen them rip open dog rose hips, discarding the pulp to purely get at and eat the numerous seeds inside, thereby not distributing the seeds.

*Wasps, in terms of what use are they, (a question I am forever asked!), besides being efficient predators of many garden pests, recent research has found that wasps are extremely beneficial as pollinators of ivy, the berries of which provide food for birds, e.g. blackcaps, which use ivy berries as an important food resource.