The value of flowering hedgerows

The loss of many farmland hedgerows shortly after the Second World War was disastrous for pollinating insects in our rural landscape. Flowering hedgerows are excellent for food, shelter and nesting sites, as well as providing a safe and convenient corridor for ease of movement.

DSC_0507

Rural communities lamented the loss of the flowers which were a distinctive and much-loved element of fruit-bearing hedgerows.  Perhaps less obvious was that insects, birds and small mammals were denied a vital food source and home.

Today hedgerows are increasingly valued for their biodiversity benefits and the planting of new hedgerows is encouraged. But just as ‘Rome wasn’t built in a day’ neither is replacing hedgerows an overnight job.

A mixed hedgerow, with a variety of trees and shrubs, can have value through the entire life-cycle of pollinators. Blackthorn for example flowers early in the year – just in time to provide a vital food source for emerging bumblebee queens, solitary bees and honey bees. Farms with hedgerows help pollinators and enjoy many other benefits.

Ballathie-D6668

Hedges provide shelter for livestock (in both cold and extremely hot weather), , ,  increase the potential for carbon capture and storage in woody biomass, improve water infiltration rates to soil, reduce the potential for flooding and create wildlife corridors across farms. They provide habitat for essential wildlife, including beneficial insects and pollinators. As we increasingly look for Integrated Pest Management solutions pollinating insects provide natural pest control.

We know that pollinators, be they in a rural or an urban setting, need good food sources from early spring to autumn, in order to complete their life-cycles.

DSC_0515

Flowering hedges that contain pussy willow, hawthorn and blackthorn are great for those insects on the wing early in the year, whilst come April and May hawthorn and wild cherry can be superb food sources for pollinators. Add to the mix dog rose, guelder rose and hazel and the potential for a hedgerow to be an all-year larder is clear.

It isn’t just the flowering of hedgerow plants that is important. At the base of hedges in amongst the tussocky grass, or vacated mammal holes, bumblebees might nest.  Bare earth under a hedge (especially if south-facing), might also provide potential nesting sites for solitary mining bees. A range of pollinators from beetles to moths and butterflies will also find those sites useful for overwintering.

In short hedges can be havens for pollinators

 

Managing hedgerows to benefit pollinators

Key to hedgerows being a bonus for pollinating insects is allowing them to flower. Many hedges only really flower on wood that is at least a couple of years old.

As well as planting or managing a range of native flowering shrubs it is important to rotate how often and when hedges are cut. This will reduce costs and be better for wildlife. Many varieties of  tree and shrub species only flower on second year growth, hawthorn and blackthorn, for example, benefit from not being cut every year.

Allowing hedgerows to flower, by moving away from the model of a tidy, short hedge, towards managing one which isn’t flailed annually is one very positive action that farmers can take. Cutting hedges is not permitted between 1 March and  31 August under cross-compliance rules. to prevent damage to  nesting birds.

Plugging gaps in hedgerows with native flowering shrubs keeps a wildlife corridor intact and leaving the occasional tree to grow above the rest of the hedge will add diversity.   A recent survey of Scottish native wild apple trees found a number associated with field margins.

Consider cultivating flower-rich strips next to hedges. Flowers such as knapweed, clovers and vetches are great for pollinators.

Aim to cut hedges in rotation, across the farm and aim for an ‘A’ shape, where the densest area is at the base. This will encourage the hedge to thicken up and provide valuable shelter beneath the hedgerow.

By managing a hedge to help pollinating insects you benefit insects, birds and mammals as well as encouraging pollinators onto your farm. Further information on all aspects of hedge management can be found on the Hedgelink website.