New hedgerow planting hits a high note

CREATION of new broadleaf woodland and commercial conifer plantation continues to create the excitement and receive all the publicity, but new hedgerow planting is setting the pace in England and Wales.

Nursery owners/managers like David Gwillam at Prees Heath Forest Nurseries, near Whitchurch in Shropshire, are facing unprecedented demand for hedgerow mixtures, as farmers cash in on Mid Tier and Higher Tier Countryside Stewardship agreements. David Gwillam thinks farmers are snapping up Higher Tier grants because they perceive a limited lifespan for such subsidy and support.

Hedgerow planting has some big guns on side. The UK Committee on Climate Change fired a shot in 2019 with recommendations for a 40 per cent extension in the hedgerow network as part of the UK target for net-zero carbon emissions by 2050. Natural England went even further with a recommended 60 per cent increase in the cause of biodiversity, to take the country’s hedgerow network to 882,000 km, enough to encircle the earth 20 times over with bushels of bushes to spare.

Scope aplenty for hedgerow planting seen here across this landscape from Bilsdale to Easterside Hill on the North York Moors.

However, before we get carried away, these increases won’t restore all that has been lost since the Second World War. Various figures put losses at 5,000 km per year between 1946 and 1963, with today’s hedgerow stock in some parts of the country only half of what it was in 1945. The Forestry Commission suggested there was about 1 million km of hedgerow in the UK in the 1950s. By 2007, the Countryside Commission had put the figure at 477,000 km, thus supporting claims that UK hedgerow stock was halved over that period of time.

Loss not only occurs from hedgerow removal but also from long-term lack of hedgerow management, meaning important functions like stock-proofing and habitats for wildlife are essentially lost from ‘zombie’ hedges.

By 1986 the UK Government had finally twigged the scale and cost of these continuing losses and accordingly introduced limited safeguarding measures for the country’s hedgerow stock. However, the decline continued unabated with a further 130,000 km of hedgerow lost during the next 10 years. Hedgerow haemorrhage continued into the 21st century with 26,000 km lost between 1998 and 2007, representing a further 6.1 per cent decline in the hedgerow stock.

We clearly have a long way to go before restoring hedgerows to their former glory. However, preparing, planting and managing new plantings to create healthy established hedgerows requires a lot more than just picking up government funds and putting trees in the ground. Strict eligibility and requirements, including site history, tree species used and the timing of work carried out are set out for the ‘planting new hedges’ item (BN11) within the Countryside Stewardship scheme.

Common lime produces prolific epicormic growth low down on the bole of the tree. The feature has allowed these common lime trees to form the fabric of the hedgerow in addition to their main function as mature hedgerow trees.

Planting of new hedges – eligibility and requirements

An apparently generous £11.60 per metre is paid for the total length of boundary (not for each side) and is available for Countryside Stewardship Mid Tier, Higher Tier and Capital Grants, although proposed new plantings are only eligible if established on one of the following sites:

Former hedgerows as shown on historic maps or other records.

Where new hedgerow creation would extend or link existing lengths of hedgerow.

Where creation of new hedgerow will help reduce soil erosion and run-off.

Where the proposed hedgerow is close to slurry or digestate stores, livestock housing or free-range areas for poultry or pigs, and where hedgerow creation will clearly help capture ammonia emissions.

In all instances, the applicant must have hedgerow management control of both sides of the boundary.

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Common elder ticks both the blossom and berry boxes but produces a gappy hedge.

SPECIES, PLANTING AND IMMEDIATE POST-PLANT MANAGEMENT

Must-dos for ‘Planting new hedges’ item (BN11)

Planting must be carried out between 1 November and 31 March using locally occurring native species. Ground preparation along the designated 1.5 m strip to achieve good soil conditions and minimal weed competition requires application of herbicide, but only during the August and September period prior to planting.

Planting material must comprise native species occurring locally, with no single species making up more than 70 per cent of the mix. Other requirements relating to planting material include use of 2-year-old transplants, which are at least 450 to 600 mm high to be planted in a staggered double row 40 cm apart with at least six plants per metre. Newly planted trees must be kept free of weeds until they are established, with any individual tree guards or tree shelters removed post-establishment. All tree failures must be replaced during the following season.

The new hedge should be trimmed for the first two years post-planting at least, to encourage bushy growth through side-shooting while permitting the new hedge to grow taller and wider at each subsequent cut. Damage to the hedge from livestock and grazing animals must be prevented by setting fencing at least 1.2 m from the centre of the hedge, or, if there is a bank, as close to the base of the bank as possible.

Holly has always been a popular hedgerow tree. This one is a veteran pollard.

Useful advice but not a requirement

So, what does the above skeleton of must-dos look like when some advisory flesh is put on its bones? New hedgerow site selection should consider existing hedgerow and woodland. And, where possible, to extend and improve on existing pools of biodiversity, using new hedgerow as an extension, avenue and corridor for wildlife.

Opportunities to connect two areas of coppice or woodland should be high on the list of priorities. Provided one of the above criteria (1 to 4) for eligibility is met, formation of so-called green lanes, whereby a hedge is established on both sides of a lane or track to create a shelter with added warmth, and therefore an ideal habitat for biodiversity, is considered to be a particularly good strategy.

The permitted period for planting from 1 November to 31 March can be narrowed down depending on environmental conditions. November is generally considered the best time, but ideally no later than December to give the small hedgerow trees a chance to establish over the winter period. Taking advantage of this early window within the permitted period is especially important when planting into clay soils.

Planting should never be carried out in freezing conditions or into waterlogged soils, irrespective of soil type or plant species. The ground should be prepared so that the soil is friable with a crumbly texture and free of any other plant growth, even if some of the species are ones you will want to encourage for biodiversity when the hedge is established. Remember, a plant can still be a weed even if it is the right plant in the right place but at the wrong time.

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With regard to planting mix, one of the must-dos is that no single species must make up more than 70 per cent. However, in the advisory ‘non-required’ small print it says if the local landscape is characterised by a single hedgerow species, then the planting mix should reflect this. If not then one of either hawthorn, blackthorn or hazel should make up at least 70 per cent of the mix. ‘Minor’ species in the mix should be intermixed and planted randomly with the main species rather than in a block or blocks within the length of the hedgerow.

Unfortunately, not everybody likes blackthorn (Prunus spinosa).  According to David Gwillam, who has been selling hedgerow mixes all over the country for more than 40 years: “Blackthorn is like Marmite – some love it but others loathe it, often depending on the part of the country.”

Other problems may arise when specific plant stock becomes exhausted. Guelder rose (Viburnum opulus) is in demand for high-pH soils due to a tolerance and liking for chalky and limestone substrates, although the species generally does well on a wider range of soil types.

By March 2021, Prees Heath Forest Nurseries had exhausted its stocks of guelder rose. “We advised our customers to take wayfaring tree (Viburnum lantana) instead due to a similar soil profile preference and, if anything, being more chalk- loving than guelder rose,” David Gwillam told Forestry Journal.

Species selection will also be determined by what the landowner sees as the major future benefits of their new hedgerow. Blossoming and berry-bearing species like hawthorn, blackthorn, dog rose, dogwood, guelder rose and others are obvious choices when wildlife and biodiversity are at the forefront of thoughts.

Common elder is an exception and contentious in this respect, although ticking both the blossom and berry boxes. Sambucus nigra furnishes an abundant food source through its white, sweet-scented flowers in late spring and bunches of juicy, purple-black berries in late summer, but is generally associated with gappy hedges in poor condition and clearly not stock-proof. Faster-growing species like willow, sallow, hazel, gean, field maple and alder will more likely top the list if carbon capture or woodfuel are the main aims.

Dutch elm disease reduced millions of mature hedgerow elms to hedgerow shrubbery courtesy of the erstwhile trees’ root sucker growth.

Chemical weed control is also required throughout the first growing season to manage highly competitive woody or herbaceous invasive weeds like bramble, stinging nettles and grasses. These weed plants can significantly reduce growth rate and impair establishment of newly planted hedgerow species by competing fiercely for water, soil nutrients and light. Use of herbicides is not everyone’s cup of tea but weed control by strimming is not recommended due to the risk of mechanical damage.

Be that as it may, plants that are classed as weeds during the early years of a new hedgerow may be considered as useful, indeed essential, later on. For instance, patches of nettles provide food plants for the larvae of highly rated British butterflies, including the peacock, red admiral and small tortoiseshell.

Hedgerow plants require post-planting protection from herbivory caused by wild mammals – rabbits, hares and deer. Spiral tree guards are standard fare on practical grounds and cost considerations. The primary practical benefit is their flexibility and ability to unravel as the trees mature. The overlapping design and ability to grow with the tree allows for the measured growth of basal side shoots, thus avoiding a growth void at the base of the hedge, as well as the strangulation of fast-growing seedling trees. Seedling trees are thus protected against herbivory and also from herbicide damage during chemical weed control.

An early autumn scene on the outskirts of North London, on land which was once part of the Enfield Chase before the ‘forest’ was enclosed in the late 18th century. A line of 200 year-old oak trees mark out the location of hedgerow planted at that time but removed some 60 years ago leaving the hedgerow oaks in place.

Once spent, plastic tree guards should be removed from the landscape for both environmental and aesthetic reasons, although extra investment in biodegradable guards will avoid this problem. Fences will need to be installed if livestock are grazing the land and should be established sufficiently far away from the new hedge so that it can eventually achieve a width of at least 1.5 m.

ALL BETS OFF FOR HEDGEROW TREES

There are no must-dos for hedgerow trees, although the non-mandatory advice section says: “Consider planting new hedgerow trees if they are characteristic of the local landscape.”

But that’s not enough for me. I believe hedgerows without trees are aesthetically downgraded even before you start to consider more functional benefits like food for insects and birds and shelter and shade-enhancing habitats for a wider range of biodiversity. However, recent pest and disease developments have restricted traditional tree choices, leaving farmers and even experts scratching their heads about what species, if any, to plant.

Spiral tree guards have clearly done their job well but are still in place, creating a bit of a diversion from an otherwise excellently groomed hedgerow.

Up until the 1970s, English elm (Ulmus procera) was the most frequent hedgerow tree over large areas of England, with English oak (Quercus robur and Q. petraea) and common ash (Fraxinus excelsior) up there as well in the top three. Dutch elm disease (DED) destroyed English elm as a mature hedgerow tree some 40–50 years ago, relegating the species, through its root suckering capability, to an integral part the hedgerow shrubbery.

The days of common ash as a hedgerow tree are now numbered since the arrival and rapid spread of ash dieback over the last eight to 10 years, albeit in a less targeted way than DED and, as such, over a much longer timescale.

English oak is suffering under the strain of acute oak decline and oak processionary moth (OPM), although neither on its own appears to be a serious threat to the existence of the species. That said, no one knows what might happen when oak trees start to face a combined attack from OPM and an acute tree decline with bacterial pathogen implications.

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So, what else is on offer? The flowers of native small-leaved lime (Tilia cordata) and large-leaved lime (Tilia platyphyllos) are powerful attractants for pollinating insects. Common lime (Tilia x Europaea) is just as attractive to insect life but is much less frequently mentioned. However, I have seen common lime, planted as hedgerow trees decades ago, now forming an attractive component of the hedgerows in south Hertfordshire. These naturally occurring hybrid trees (Tilia cordata x Tilia platyphyllos) produce prolific epicormic growth low down on the tree trunk. As such, they now form an integral part of the hedge as well as being hedgerow trees in their own right. Perhaps the single biggest thing against common lime is not being regarded as a classical native tree species. However, this naturally occurring hybrid apparently first appeared in England and as such is clearly not more native to anywhere else.

Recently planted pure hawthorn hedgerow, complete with spiral tree guards.

Other tree species observed as mature hedgerow trees are crack willow (Salix fragilis) and white willow (Salix alba), or hybrids of the two – good choices for wet areas. Also hornbeam, despite its inherently slow growth rate and generally being regarded as only fit for coppice. Good sources of information on hedgerow trees are history books on the countryside where a whole range of otherwise unconsidered species spring up – crab apple and wild pear planted since medieval times for the fruit, and holly as fodder for livestock.

John Evelyn (Sylva, 1662) said common or Persian walnut (Juglans regia) was a common sight across the Surrey Hills. However, 18th-century activities including furniture making and colonial wars (walnut was the number-one choice for gun stocks) finished this species of walnut as a frequently found tree in England. Edward Step (Wayside and Woodland Trees, 1904) described how a few of these very old walnut trees or their descendants could be found in the lanes and hedgerows of Surrey during the second half of the nineteenth century.

Common walnut is not a native tree, but neither was English elm, both having a 2,000-year provenance in the Britain Isles through introduction by the Romans. Contemporary landowners should take a punt on common walnut as a hedgerow tree. Potential rewards in the longer term include timber unrivalled in quality and value and a good crop of nuts, provided you can distract or otherwise deal with any grey squirrels in the locality. By the same token, what’s wrong with sweet chestnut as a hedgerow tree, with its similar 2,000-year provenance in the British Isles?

Ancient history books on the UK countryside tell us that crab apple trees were widely planted as hedgerow trees. However, hedgerows require proper management lest they over-grow the relatively small and slow-growing crab apple trees.

The last word on hedgerow trees goes to David Gwillam, who singles out sycamore as grossly underrated as a hedgerow tree. Sycamore produces a dense canopy, good timber, and is attractive to a range of insects including aphids, which in turn attract ladybird beetles and other predators. As yet, sycamore is unaffected by any significant insect pest or disease.

Sycamore (Acer pseudoplatanus) is extremely wind-tolerant and therefore an ideal candidate for planting as a hedgerow tree in more exposed regions. Dr Roderick Robinson from North Yorkshire has commented on how sycamore along with ash is the most common hedgerow tree in his own neck of the woods. However, given their prolific and efficacious, wind-generated seed dispersal mechanisms it is difficult to say with any certainty what proportion of these sycamore and ash trees were actually planted as hedgerow trees. Sycamore’s close relative Norway maple (Acer platanoides) should also be a prime candidate for hedgerow trees, although, unlike sycamore, it has absolutely no claim to being a native species.

Sycamore is not traditionally regarded as a native tree, although unlike other naturalised, domiciled tree species (e.g. English elm, sweet chestnut, common walnut and white-flowering horse chestnut) no one has ever accurately identified or even pinpointed the period when sycamore was supposedly brought into the British Isles. With recent and revised interpretation of Acer pollen records, some now believe sycamore is native. The argument around the provenance of sycamore is not an overnight phenomenon, it having raged for some time (Harris, E., 1987, ‘The Case for sycamore’, Quarterly Journal of Forestry 81, 32–36).

USE IT, DON’T LOSE IT

When hedgerows disappear, we lose a lot more than lines of mixed shrubbery and the odd mature tree. We lose an important part of our history and cultural heritage. It was Oliver Rackham, Britain’s foremost countryside historian, who said: “The probability is that the Romans found Britain an already hedged land.”

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