Planting hedgerows for wildlife

Ecologist’s regularly have to advise on the design and species mix of habitat mitigation and enhancement measures, but are we always getting it right?  In this article, Oonagh Nelson provides clarity on planting hedgerows for wildlife…

We all know hedgerows are good for wildlife – providing safe harbour from predators and the weather, while also comprising a source of food and a natural highway linking up habitats.

Yet new hedgerows often fail, with some doomed before they have even been planted through poor consideration of species selection, planting density or inappropriate location.

I’m writing this in November as my inbox fills up with reminders and offers that root ball and bare root hedging stocks are now available from a host of suppliers.

But where should any ecologist or landowner planning a new hedge start and what is there to consider?

Plenty of online sellers offer ready to go mixed selection packs for native hedging, which is a good option and I personally think any habitat enhancement can only be a good thing. With wholesale changes to environmental protection looking a risk post-Brexit, any habitat enhancement or creation is a positive.

However, if you have the option to specify a plant list for a scheme maybe as part of a habitat management plan, then consider a selection that requires the least maintenance rather than diversity! “What?!” I hear you say, “surely as a professional ecologist I should be pushing for the most glorious of flora Botanica that I can?”

Sadly in my 17 years’ experience, I have often found that all of the financial and labour resource investment is thrown into the early days of a development project. Meaning you probably can specify the best, biggest and rarest plants you want and they will get planted if it means building works can crack on. Yet getting a purchase order to come back to weed and feed, trim and chop is like pulling teeth, which would mean that all your efforts could go to waste.

I should point out if you haven’t already guessed, that the advice I’m offering here is really intended for ecologists redressing loss of biodiversity for imminent construction related activities, bound by deadlines, budgets and future changes to land ownership. That’s not to say that you can’t achieve a measurable overall gain by following this advice – so please do read on!

My top pick for specifying a new native hedge is to include hawthorn and plenty of it – in fact some say a planting mix should contain 75% hawthorn. Well hawthorn is a great hedging stock as it is hardy, bears fruit and takes easy root in nearly every soil type. If you’re after a bit more of a mix, I’m also a fan of elder and holly.

Next you need to specify holly in abundance in the mix ratio as it’s slow to mature. I find for a nice dense hedge the holly numbers need to be upped or planted in little clusters all together for maximum impact.

Another species to consider is blackthorn which always takes very well just like the hawthorn, forming a dense thicket making it hard to penetrate and therefore less likely to get trampled on or pulled out by anyone looking for a shortcut. Hazel (an alternate food source for wildlife), dog rose and guilder rose are also commonly used as is gorse.

Personally, I have never been a fan of stocking gorse. Depending on the habitats nearby, if this plant is allowed to get out of hand it is likely that at some point in the future the landowner may be forced to remove it, in doing so eradicating the new hedgerow!

There are plenty of edible options for foraging, particularly if you want to consider adding in some trees to the mix for variety – cherry, crab apple, pear and plum for example. A proper bounty!

To give your new hedge the best chance of survival I would recommend that you include as much aftercare in the first year or so of planting. Assuming that development works are ongoing on site, because whilst the developer is still active, this usually presents the best likelihood of them wanting to ensure that all new planting is establishing well and looking well. The site and the works will likely be subject to planning conditions and so any issues will be keenly rectified.

If I’m sounding very cynical here, I assure you this is based on my experiences.

Hedging for wildlife should, once planted, be given a good harsh trim! I get called to undertake habitat maintenance works often on jobs where I have not planted the hedge in the first place, and typically what I find is a hedge that is well stocked, nice diversity of plants etc. etc. but… it was planted and left. Just left to get on with establishing itself. Which for the most part it will, like a slow sky rocket stretching up towards to the sun, its naked spindly single trunks like pale knobbly knees knocking in the wind and providing no shelter for fauna at ground level whatsoever. In fact, given enough time, the only fauna that would be able to avail of any fruits it bares would need to be pretty tall or take flight.

To avoid the lolly popping of your new hedge, give it a good harsh trim back after planting. Up to a third of the height, or if the plant has a good show of buds lower down the stem, then anything up to half can be trimmed off – be careful though and check for buds first. This is based on having planted a hedging whip of approximately 40-60 cm. Also pencil in to return the following year and repeat this harsh cut, with the sides and lead shots being trimmed back the following winter.

Sometimes we will be asked to plant up to 1m whips, which are more expensive and do not offer any guarantee that they will establish better or faster. Particularly if they lack buds lower down the stem and you are trimming them in half, for example if they are already lolly popped!

To increase the readiness of the new hedge as a wildlife refuge, you should look to plant 8 whips per metre in a staggered double row. The use of rabbit guards will very much depend on the risk of predation on the new plants, but bear in mind that someone will need to try and secure a purchase order at some point, most likely post development works, to come back and remove those guards. Which if by such time the site is done and dusted and handed over to whoever, this aftercare might never happen. Guards need removing at 3-5 years post planting.

Oh – and before I forget, location! Location location location. Well to be fair, many times us ecologists get what we are given – whatever is left, not suitable for a garden, or surplus to requirements. If that bit of land is surplus to the requirements of the sites’ public open space, there is usually a reason for that – access. Keep in mind that your new hedge will require maintenance to get the best out of it, the grass will need trimming back from around the stems, mulch will need applying and all the trimmings and off cuts will usually need removing from site or piling up in an informal habitat pile. As that hedge matures, is there going to be a tight squeeze for any contractors undertaking the work?

Timings for commissioning planting:
Best time to plant: November to March, avoiding periods of heavy frost.
Best time to trim: November to February, avoiding nesting birds.

Hope you enjoyed this article. It’s not designed to be a planting how to, but more a knowledge exchange on what to consider if you are the ecologist putting together the management plan or planting specification for a scheme. I’m lucky enough to get to both specify and plant, wearing the hat of both an ecologist and a habitat contractor and I’m happy to chat about hedges and habitats should you have any queries.

About the Author: Oonagh Nelson is the Founder and Director of Contract Ecology Ltd, a conservation led consultancy and contracting firm specialising in habitat creation and protected species mitigation. Oonagh is a professional ecologist of 17 years, she holds licenses for bats, barn owls, great crested newts and badgers. A full member of CIEEM and an associate member of RICS. She is also a trained plant operator and a dab hand with a chainsaw. If you have mitigation that you need to implement, or a habitat that needs translocating or enhancing but are unsure how you’re going to do it, then get in touch with Oonagh for some helpful advice at enquiries@ContractEcology.co.uk.