← All guides · Species & planting · October 2026

Mulching a new hedge: woodchip or biodegradable mat?

Once you have planted your hedge whips, the single most important thing you can do in year one is keep the base weed-free and retain as much moisture as possible around the roots. On the chalky, free-draining boulder clay around Goodnestone, Chillenden and Knowlton, where summer rainfall is patchy and east Kent averages barely 550mm a year, that establishment moisture is not a given. The practical decision almost every new hedge planting arrives at is this: loose woodchip mulch or a biodegradable weed-suppressing mat? Both work. Both have genuine drawbacks. This guide sets out the honest trade-off before giving you the recommendation for this particular soil and setting.

Why mulching matters on chalky east Kent soil

East Kent sits in one of the driest corners of England. The chalk-over-clay soils around Goodnestone drain freely after winter rain and then cap hard when they dry out in spring, forming a surface crust that sheds further moisture rather than absorbing it. Newly planted bare-root hedge whips have little root storage to buffer a dry spell in April, May or June. Without mulch, competing grass and weed growth steals the available moisture that the young hedge actually needs. Trials by the Woodland Trust show that failing to mulch new whip plantings is the single biggest cause of poor establishment in the first two seasons. A 60-90cm wide, 7-10cm deep mulch strip along the entire run is not optional if you want reliable first-year growth.

The decision: woodchip or biodegradable mat?

Pros of loose woodchip mulch

• Very low cost, sometimes free. Tree surgeons in and around the Wingham area regularly need to dispose of fresh chippings. If you ask when booking hedge or tree work, a load of fresh woodchip costs nothing except the delivery or collection. For a 50-metre hedge run at 90cm width, you need roughly 3-4 cubic metres of woodchip to achieve a 10cm layer, which is a realistic ask from a single day's tree surgery.
• Improves soil structure over time. As the woodchip breaks down over two to three years, it adds organic matter to the chalky clay. This genuinely benefits long-term hedge establishment, improving moisture retention and encouraging the beneficial mycorrhizal fungi that many native hedge species, including hawthorn, hazel and blackthorn, rely on for efficient nutrient uptake.
• Looks naturalistic from the outset. On a field-boundary planting or a garden hedge that runs alongside old parkland, a woodchip strip is visually appropriate in a way that a black weed-suppressant mat is not.
• No anchoring or cutting required. A mat requires cutting slits and anchoring pins around each plant. Woodchip is spread from a barrow, which is straightforward on a long run.

Cons of loose woodchip mulch

• Voles and mice use it as cover and will girdle young whips. This is the most serious practical risk on the chalky farmland around Goodnestone and Chillenden. Short-tailed field voles and wood mice travel under a woodchip mulch layer to access the soft bark at the base of young hedge whips. Girdling, where the rodent strips a ring of bark completely around the stem, kills the plant above that point. On a planting that carries an individual tree tube per whip, the tube usually prevents this; without tubes, woodchip plus high vole pressure is a genuine risk to establishment.
• Needs topping up each year for the first two or three seasons. Fresh woodchip decomposes over 18-24 months, and the layer thins. A second top-up in year two is usually needed to maintain effective weed suppression and moisture retention. This costs time and means sourcing a second load of material.
• Fresh green woodchip can temporarily draw nitrogen from the surface soil layer. This is a short-term effect, typically resolved within a growing season, but it can slow early growth of young hedge whips planted directly into fresh chips. Ideally, use chippings that have been composted for at least 6-8 weeks before applying, or keep fresh chips away from the immediate base of each stem.
• Wind can scatter light woodchip on exposed sites. On an open field boundary running east-west in the Goodnestone to Chillenden direction, a strong prevailing wind can redistribute a loose chip layer over the course of a winter.

Pros of biodegradable mat (jute, coir or cardboard with a woven surface)

• More reliable weed suppression in the critical first two seasons. A properly laid biodegradable mat creates a consistent barrier across the full width of the mulch strip, which loose chip does not unless it is applied very deeply and topped up. For a formal garden planting near a listed building or in a managed parkland setting adjacent to Goodnestone Park, the neater weed suppression of a mat is often worth the extra cost.
• No vole cover. The mat lies flat against the soil surface and gives rodents much less cover than a loose chip layer. For plantings without individual tree tubes, this is a meaningful safety advantage in a high-vole area.
• Better moisture retention in the first growing season. A mat holds moisture beneath it more consistently than loose chip, and on the free-draining chalk profiles around Goodnestone it can be the difference between a whip that survives a dry May and one that does not.
• Single application. A good quality biodegradable jute or coir mat will last two to three growing seasons before it degrades sufficiently to need replacing. By that point, the hedge whips should have enough root depth to be past their most vulnerable establishment phase.

Cons of biodegradable mat

• Noticeably more expensive than woodchip. A roll of 1m-wide biodegradable weed-suppression mat costs roughly £1.20-£2.50 per linear metre from a UK horticultural supplier, depending on material and weight. For a 50-metre hedge run, that is £60-£125 just for the mat, plus the cost of the pin anchors. Woodchip over the same run, sourced locally, costs a fraction of that.
• Does not improve soil biology. A mat suppresses weeds but adds nothing to the soil structure over time. On the thin chalky soils around Goodnestone, the organic matter contribution from degrading woodchip is a genuine long-term benefit that a mat cannot replicate.
• Needs careful placement around each stem to avoid stem rot. The mat must be cut and folded so that it does not press against the bark of the whip. If the material stays wet and sits in contact with the stem over winter, it can encourage fungal rot at the base. This is a relatively easy mistake to avoid but it does require attention at installation.
• Polythene or woven-plastic mats should not be used. This site uses only biodegradable materials: jute, coir, hemp, or thick corrugated cardboard under a thin layer of chip. Non-biodegradable black plastic mulch mat is effective as a weed suppressant but fragments into microplastic as it degrades, which is unacceptable on agricultural land or in a countryside setting around the park boundary.

The recommendation: match the method to the planting type

For a typical field-boundary planting of native whips on chalk farmland between Goodnestone and Chillenden, loose woodchip is the better choice if you can source it from a local tree surgeon and apply it at 10cm depth over a full 90cm wide strip. The soil benefit over time, the low cost, and the naturalistic appearance all support it. If the planting is in an area with known high vole pressure and you are not using individual spiral guards per whip, either use a biodegradable mat or fit spiral guards before laying the woodchip.

For a formal garden planting close to a listed building or within the setting of Goodnestone Park, a biodegradable jute or coir mat is the cleaner option. It looks better against the Park's character landscape, provides more consistent suppression in the first two seasons, and reduces the labour of a year-two top-up. The extra cost is proportionate to a higher-value planting where individual whip failures are more visible.

Either way, the width matters more than the material. A 40cm-wide woodchip strip is markedly less effective than a 90cm-wide one on this soil type. The grass and dock that frame most field boundaries in this area are vigorous competitors and will close in from the sides if the strip is narrow. I always advise a minimum 60cm width, and 90cm where the existing weed burden is high.

Aftercare in the first growing season

Whichever mulch method you use, two things still matter in year one. First, water newly planted whips during any dry spell in April, May or June if rainfall falls below about 15mm per week. On the free-draining chalky profiles between the village and Chillenden, a dry fortnight in late spring is enough to stress a bare-root whip that has not yet established new roots. A slow trickle from a container, 3-5 litres per plant, twice a week during a dry stretch is usually sufficient in year one. Second, check the mulch strip in September and clear any vegetation that has bridged the gap from the sides. Annual meadow grass, creeping thistle and common dock all root quickly into a woodchip strip that has thinned over summer.

Sources: RHS, mulches and mulching guide (rhs.org.uk); Woodland Trust, hedgerow planting and management guidance (woodlandtrust.org.uk); Wildlife and Countryside Act 1981, section 1; Natural England, hedgerow management guidance for Countryside Stewardship.