Established 1864
Sustainability and Biodiversity; Our Approach
GREAT BRITISH TREES
‘Inspiring the creation of green living spaces for now and the future’
Welcome
Hillier Nurseries has a rich history in developing horticultural techniques which work with nature in a sustainable way. Our focus is on producing high quality, great value, British grown trees.
We know our customers share our passion, which is why we wanted to provide an insight into how we operate – how we consistently produce beautiful trees, more sustainably, while improving biodiversity.
The Hillier team and I are on an amazing journey, with each day bringing exciting new learnings and ongoing improvements to our operation. Enjoy your read!
British-Grown Trees for Sustainability
As sustainability becomes increasingly important, the role of trees in combatting climate change, supporting biodiversity, and improving the environment is clear. But where these trees come from is crucial. British-grown trees, grown locally, play a significant role in promoting sustainability. Here’s why they are vital for our environment:
Reducing Carbon Footprint
British-grown trees help reduce the carbon footprint associated with transportation. Unlike imported trees that travel long distances and contribute to carbon emissions, locally grown trees eliminate the need for such transportation. This makes them a more sustainable choice.
Supporting Local Biodiversity
These trees are naturally adapted to the UK’s environment, making them perfect for supporting native wildlife. By planting British-grown trees, we ensure that our landscapes harmonise with local biodiversity, providing habitats and food sources for species that are already here.
Ensuring Biosecurity
Importing trees poses a risk of introducing pests and diseases, like the devastating Ash Dieback. Dutch Elm Disease, and Oak Processionary Moth. By prioritising British-grown trees, we reduce the risk of harming local ecosystems and protect the health of our landscapes. Locally sourced trees help resources within the UK, reducing the need for imports, and supporting sustainable practices.
Climate Resilience
British-grown trees are naturally suited to the UK’s climate, making them more resilient to local weather patterns, including those brought about by climate change. Home-grown trees are more likely to thrive, ensuring that planting efforts are successful and sustainable.
British-grown trees offer numerous sustainability benefits that imported trees cannot match. By choosing local trees, we protect our environment and make our efforts to combat climate change more effective and sustainable.
Adam Dunnett Director
BIOSECURITY
The genuine and concerning threat to our environment largely arises as pests and disease enter the UK through imported trees. Over the last decade, there has been a significant increase in both the occurrence and intensity of these. Open borders, lack of resources, and the growing volume of imported plants have significantly accelerated the introduction and spread of various pests and diseases, including Ash Dieback and Oak Processionary Moth. These destructive invaders can have far-reaching consequences, affecting both urban and rural environments. Our industry needs to do everything within its power to prevent further pest and diseases from entering the UK.
That’s why Hillier Trees: -
Have a robust biosecurity policy which is regularly reviewed and updated. Are holders of three key biosecurity and environmental accreditations.
• Operate a zero-tolerance approach to biosecurity and will not import trees that are host to major pests and diseases from infected areas. Grow trees within their fields for a minimum of five years.
Use their own field grown stock for container tree production.
Hillier operates a zero tolerance approach to biosecurity and will not import plants that are host to major pests and diseases from infected areas.
Oak Processionary Moth
Leaves affected by Ash Dieback
Dutch Elm Disease
Learn more about Biosecurity on our website hillier.co.uk/trees or download our full Hillier Tree Guide by scanning this QR code.
The 10 million gallon reservoir at Hillier Container Tree Nursery.
CONTAINER TREES Container Trees
Growing Container Trees
The Starter Plant
The key to any good container tree is the quality of the field grown tree used for potting.
Four years ago, Hillier recognised the need to accelerate the production programme of starter plants, to ensure a consistent quality of trees with strong biosecurity credentials and sustainable attributes. With this vision in mind, Hillier purchased a 100-acre farm specifically for growing young trees from one year, up to three or four years.
Budded maidens are transplanted into 45L production fields and grown for a further three to four years. At this stage, they have a girth size of 6-8cm/8-10cm and have three years of formative crown pruning behind them.
Trees grown for 45L production will be transplanted three times, while those destined for 80L, 200L or larger may be transplanted four to six times.
In autumn, prior to lifting, a small group of highly experienced production team members select and tag individual trees for containers, ensuring only the best are used.
The Potting Process
In November and December, trees destined for 45L containers are lifted and placed into a reuseable, recycled co-ex bag. These durable bags protect the fibrous roots, which take over five years to develop.
They also prevent roots from drying out, which is crucial for the tree to establish successfully.
With Hillier production fields less than 20 miles from their container tree nursery, trees are quickly and directly transported to the potting shed. This method keeps the trees fresh and ensures the lowest possible carbon footprint through careful loading and direct delivery.
Before being potted by the skilled team, each tree has its roots hand pruned to encourage further development of fibrous roots once potted. This guarantees the tree is given the best start in life as a container tree. Experience is key, as over compaction of the compost at this stage can result in the reduction of the compost’s Air Filled Porosity (AFP). Oxygen levels within the compost are a critical component of effective plant root development.
Hillier uses a bespoke Melcourt 100% peat free Sylva Mix, made from recycled coir, composted green waste, and forestry byproducts. In addition to surpassing
peat-based compost in promoting tree health, this peat-free mix wins hands down on environmental soundness.
Home Grown
Hillier are avid believers in producing truly homegrown British trees. Over 90% of the Hillier 45L container trees are produced from own field production, and over 95% of their 80L and 200L trees are home grown. Some trees will have been in the Hillier fields for over 15 years and may have been transplanted four or five times.
Certain tree species are unable to be grown commercially in the cool and increasingly wet Hampshire winters but are still good options for British landscapes once established. For these, Hillier buys in starter plants from carefully selected partner nurseries they have worked with for years. The production team visits these nurseries annually to select the required stock.
Watering
All 45L, 80L and 200L container trees are watered using 100% rain harvested and recycled water. Hillier has a 10-million-gallon reservoir (see page 4) fed by two smaller reservoirs, one of which is from a water capture system. Water is captured from roofs and carparks of a neighbouring housing estate, before being filtered, held in a pond reservoir, then pumped into the main reservoir.
In addition to irrigation, the reservoir provides numerous advantages particularly when it comes to wildlife conservation. The reservoir area serves as a sanctuary for migratory waterfowl such as ducks and Canadian geese, offering them a place to rest and nest. Herons have been observed at the edge of the water, patiently waiting for prey. During spring, the water teems with life as frogspawn and newts can be spotted, and in summer butterflies, dragonflies and bees revel in the wildflowers. Autumn means a diverse array of fungi emerges, adding to the biodiversity, and in winter, the reservoir freezes over, creating a secure habitat for the inhabitants that call it home.
Hillier trees are watered using an efficient drip irrigation system. Each container is hooked up with a minimum of two drip tubes that release water in the form of small droplets. These seep into the soil evenly and gradually. By targeting the root zone, water loss through evaporation and runoff is minimised.
After Care
Over five years of careful production in the Hillier fields results in a strong, well-balanced tree, but the drive to supply the highest quality tree is an ongoing process. The container production team prunes every tree in the early spring after potting, and undertakes a light summer prune if required.
Each container is staked with a bamboo cane which typically lasts for three crops. The cane is securely tied to the tree to maintain that all important straight leader.
The Production Team
Hillier container trees are potted and grown on by a small, very experienced team, led by Martin Hillier. Born and raised on the nursery, Martin has been part of the tree production unit for over 35 years and is a true plantsman and skilled grower. Martin’s righthand man, Mike Wells, joined Hillier in 1975 and in nearly 40 years has become one of the most complete tree nurserymen in the UK. Martin, Mike and crew have spent the last 15 years developing the art of growing trees peat free, using only recycled water and with minimum use of fertiliser and chemical. Their trees must be the most sustainably produced commercial tree crops in the world - but the team will tell you they are still learning every day!
Martin Hillier
Hillier Director and Manager of Broadmead Container Nursery.
FIELD TREES Field Trees
With over 430 tree production years between them, the highly experienced Hillier team understands effective and sustainable growing.
Senior Production Manager and Hillier veteran of 35 years, Phil Hall, heads up a crew of 23 people – all passionate about the work they undertake. Their goal is to grow outstanding trees commercially, but in a manner which enhances the environment and works synergistically with nature.
To support this vision, the company adheres to the internationally recognised standards of ISO 14001, the environmental management accreditation at the heart of the Hillier sustainable tree production. In addition, the government led scheme, Plant Healthy, helps ensure good biosecurity practices within their nurseries.
Healthy Soil, Healthy Trees
Appreciating the vital importance of soil in tree production means Hillier allows time for the soil to rest between crops, with a three-year fallow strategy. In year one a maze crop is grown with maze plants incorporated into the soil in the autumn.
In year two a natural biofumigant crop (such as sorghum grass), is grown and incorporated into the soil at the end of the summer. Fallen foliage decomposes and releases isothiocyanates, a natural biofumigant that is toxic to nematodes which can impact root growth.
In the third year natural lime is added, soil samples are taken and lime is applied via GPS spreading technology to ensure it is applied at exactly the right rate in each
area of the field to achieve the optimum Ph of 7.5. In spring, additional organic matter is added. Hillier uses composted green waste produced from gardeners’ green waste and collected by councils around the UK. They may also add natural biochar to improve the moisture and nutrient holding capacity of the soil.
Hillier only plant their trees when nature allows. The soil profile must remain undamaged. The natural mycorrhizal needs to be interacting with the roots of the trees as soon as they are planted because no ‘foreign’ imported mycorrhizal is added into the soils.
Trees are transplanted on a regular rotation; they are lifted in winter, and their roots are trimmed to promote the growth of fiborous roots. Trees are then replanted in a new field with wider spacing, ensuring ample light around the entire canopy for robust and uniform growth.
The Tree Growing Cycle
Year 1: Hillier plants rootstocks in February - March and these are budded in August.
Year 2-3: The budded maiden tree is grown on and caned to ensure a straight stem.
Year 4: Trees are lifted and transplanted to a new field. Roots are hand trimmed.
Year 4-6: Trees receive formative pruning, so a balanced crown is produced.
Year 6: Trees are lifted, and roots are pruned again. At this point the trees are either potted into 45L tree bags or transplanted into another field with wider spacing, and grown on.
Year 9: Trees are lifted and transplanted, making them 3, 4, 5 or even 6 times transplanted, as they mature into semi-mature or super semi-mature.
Water Management Trials
As mentioned before, all water at Hillier Trees comes from river abstraction and reservoir. From 2025 there will be no mains water used on any of its tree nurseries (other than in an unforeseen emergency). A programme is currently being rolled out to move to drip irrigation across all field production, with 75% of fields now under drip. Drip Irrigation is the most efficient method of delivering water to trees, enabling the production team to be extremely precise as to when, where and to what water is delivered.
For the last three years Hillier has been working with Dr Andy Hirons and his team from Myerscough University. The study has been looking at the impact on tree growth in various species, based on types of water delivery, volumes and the weather. This has led to an enhanced understanding of the water needs of different tree species, optimising growth and effectively managing the valuable resource of water.
Species & Breeding
For over 40 years Hillier has been continuously refining their tree range, to ensure the production of the most sustainable trees for enhancing the urban environment. The Streetwise range has been selected from seedlings, guaranteeing the environmental credentials of each species is not lost. Using wellcrafted propagation techniques Hillier keeps the best selected habits and maintains these in generation after generation of Streetwise trees.
Collaborating with world and European tree breeders has enabled Hillier to initiate groundbreaking and important tree introductions. These include the Resista range of Elm trees: Ulmus New Horizon, Ulmus Rebona and Ulmus Fiorente – all of which are host to the rare and endangered White-Letter Hairstreak butterfly.
Climate Resilient Trees
One of the greatest challenges the world is facing is ensuring any trees grown are able to thrive in the new norm - climate change.
Through this lens, Hillier have started trialling a range of species not commonly grown commercially in the UK and which could well provide the climate resilient tree range of the future. The work they are doing is still in its early stages, however, they have also recently commissioned The Urban Plant Institute to review their current range of trees for their climate resilience value.
Phil Hall Senior Production Manager
SOIL MANAGEMENT
Soil Management
The quality of field trees is dictated by three key things: The skill of the growers, the weather and soil quality. Hillier can proudly claim to have fantastic nurserymen and good soil management but the weather is a little tricky to influence...
Healthy Soil = Healthy Tree
Sustainable soil management is vital. Gone are the days where chemicals and fertilisers were used as an aid to producing a healthy, fertile soil. New methods rely on science and working with nature and the environment.
Pre-planting Preparation
1 - Choosing the right soil
When Robert Hillier first saw the sandy loam soil at the Hillier main field nursery, he knew it would be perfect for tree production. He outbid the competition, and stressed out his bank manager, but let the land prove its worth over time.
2 - Drainage
A network of land drains was installed to channel excess water into the ditch system. This then feeds into the reservior used for irrigating the trees.
3 - Resting the soil
Managing the three-year fallow period is critical when allowing the land time to recover. Never leave fallow land without a cover crop as this reduces soil erosion and controls weed population.
4 - Decompaction and Aeration of soil
This is critical so tree roots can penetrate the soil and access the water and nutrients which have been developed in the soil over the previous three years. It also ensures there is sufficient oxygen for the roots to survive and thrive. Soil is decompacted to a depth of 500mm - 700mm, depending on the size of trees being planted.
Soil Care & Management
Hillier carry out regular soil testing for nutrient, soil diseases, and nematode population, so they only need to give nature a helping hand if and when required. Watering is important, and 85% of the field nursery is on drip irrigation, for direct targeting to the trees root zone and eliminating run off and soil erosion.
Constant tree pruning creates a wealth of tree matter which is chopped up and left under trees to add back nutrients and organic matter to the soil.
Wide row spacing improves light influx to tree canopy for a better-balanced tree. Grass is sown down each row holding the soil together to reduce compaction. Grass cuttings add organic matter back to the soil. In addition, grass helps reduce the air temperature around the trees, improving growing conditions in the summer and encouraging more wildlife into the trees (hopefully more of the beneficial insects and fewer of the less beneficial!)
PEAT FREE
Hillier Trees are proudly 100% peat free, and British home-grown.
Growing in peat free compost is important from a sustainability perspective, however the real gold standard is to be growing in a peat free mix sourced from the most sustainable ingredients. Hillier have been working with Melcourt for the past 15 years developing and evolving their peat free mix. A collaboration with Melcourt and the Responsible Sourcing Scheme has helped achieve their goals and the Hillier bespoke peat free mix used on their tree nurseries has recently scored a B after an audit.
The Sylvamix Special prescription mix from Melcourt is a blend of Melcourt’s long-established composted woodfibre together with recycled coir and a low level of certified green compost. Melcourt are founding members and strong supporters of the Responsible Sourcing Scheme for Growing Media, which is a scheme that enables growing media users to establish an answer to the question ‘if we are not using peat, how can we be sure that the alternatives are not equally environmentally damaging?
Developing an irrigation programme which works alongside peat free production is essential to the success of growing a strong, well rooted container tree. Peat free requires a more nuanced watering approach than growing in peat and Hillier employs the ‘little and often’ tactic with watering. Achieving their production through smaller quantities of water delivered more often means an overall decrease in water usage and
nutrient leaching, as compared to production using peat-based compost. Without a doubt, peat free production is far more sustainable than peat.
“ The Sylvamix Special peat-free mix used by Hillier Trees for nearly two decades has a Responsible Sourcing Score B” (Melcourt)
Peat Free & Home Grown
Hillier Nurseries aim to be a leader in good environmental practice, developing a sustainable approach to managing waste, water and its plants.
Our Hillier Nurseries are also 85% water self-sufficient through a drainage system in which rainwater and irrigation runoff is collected, filtered, cleaned, treated on site and used to irrigate crops.
In 2018, Hillier Nurseries joined The Planet Mark. This is a certification programme that recognises companies committing to continuous improvements in sustainability allowing businesses to measure and find opportunities to reduce carbon emissions, energy and water consumption, waste, and more. Our Goal 5% reduction in our carbon footprint every year
Hillier have moved to 100% peat free growing in all their container grown plants. In 2019, the also became the first UK ornamental tree nursery to be accredited with the Woodland Trusts UK Sourced and Grown Assurance Scheme (UKSG), whilst also holding The Plant Healthy certificate and are ISO14001 accredited.
Awards & Certifications
ISO14001
In 2019, Hillier Nurseries was awarded ISO 14001 accreditation. This is a globally recognised standard, providing an agreed framework to follow regarding Environmental Management Systems. It indicates that a company is having less of an impact on the environment and has strong systems in place.
Plant Healthy
Hillier have an internal Plant Health Assurance process to ensure good practice in our purchasing and growing processes, with full documentation and record keeping giving traceability. Hillier are audited and certificated under the DEFRA backed Plant Healthy scheme.
Planet Mark
In 2018, Hillier joined The Planet Mark. This is a certification programme that recognises companies committing to continuous improvements in sustainability. Through it, companies can measure and find opportunities to reduce carbon emissions, energy and water consumption, waste and more.
UK & Ireland Sown & Grown
Hillier have been accredited with the UKISG since 2019 with a rigorous annual audit to ensure accredited nurseries grow to the highest biosecurity standards and are genuine producers of British grown trees.
British Association of Landscaping Industries
Since 2022 Hillier have been British Association of Landscape Industries (BALI) Accredited Suppliers. This means that commercial landscape contractors, garden designers, and the public recognise Hillier as the industries professional choice. Hillier aim to enhance all aspects of the horticulture industry, raising standards and promoting collaboration, with BALI providing the perfect platform for this. As BALI members, Hillier are committed to delivering the highest quality, specialist products and services.
Hillier Trees Selection
No Hillier publication would be complete without a tree selection!
We have pulled out 10 trees from our 150+ range which we feel represents biodiversity for an ever changing climate. What would your 10 trees be?
Scan this QR code to download the full Hillier Tree Guide today.
Acer campestre
‘Elsrijk’
Size: Medium
A highly popular choice for streets and avenues, this tree is known for its compact, uniform appearance. Dark green leaves transform into a stunning display of golden butterscotch, in classic maple autumn fashion.
Speciality:
Alnus glutinosa
Common Alder
Size: Small / Medium
This native tree is well-suited to wet clay areas prone to waterlogging. Its greenyellow catkins which appear in March, add a decorative touch. These harden into woody cones with winged seeds, providing year-round interest. The tree features dark brown bark with fissured striping. It’s glossy green leaves fall between October and November.
Speciality:
Betula albosinensis ‘Fascination’
Size: Medium
Ideal for urban locations with its ascending branches and uniformed and pyramidal canopy. Catkins up to 15cm long will emerge in spring. It’s leaves are the darkest green of all Betula, providing a dense, sheltered canopy, perfect for summer screening and dappled shade.
Carpinus betulus ‘Streetwise’
Size: Medium / Large
Featuring a neat, upright form and uniquely textured leaves, this tree displays a beautiful autumn colour of golden amber that lingers well into winter. Its notably larger keys make it ideal for compact urban spaces like streets or car parks. A highly practical and visually appealing structural tree with a tidy canopy.
Speciality:
Size After:
Liquidambar styraciflua ‘Worplesdon’
Size: Medium
Well-adapted to the unpredictable UK climate, this tree is highly tolerant of cold and heavy rainfall. Its leaves emerge a vibrant green in spring, transforming into a stunning array of crimson reds, apricot oranges, and marmalade golds as summer fades. This autumn display is more consistent and resilient to various site conditions than the standard species.
Malus ‘Mokum’
Size: Small
Discovered at the Henk Wansing Nursery as a seedling between M. ‘Profusion’ and M. ‘Liset’, this tree has an appealing upright ovoid shape with rose-red flowers. Its leaves emerge reddish and transition to a bronze - purple green in summer.
Prunus serrulata ‘Sunset Boulevard’
Size: Medium
Originally discovered as a seedling of Prunus serrulate Benden. Its upright narrow form was selected with tighter urban locations in mind. The spring blossom opens to a profusion of white flowers with undertones of pink. Fantastic red autumn colour and one of the finest cherries for street planting.
Speciality:
Size
Pyrus calleryana ‘Chanticleer’
Size: Medium
Establishes well in all soil types, and will tolerate harsh urban conditions and pollutions. Its slim upright canopy is the first to open its emerald green leaves in spring, and last to drop them in autumn. Elegant masses of wonderful white flowers open in April / May, which bring a much needed resource for wildlife.
Speciality:
Size
Sorbus aucuparia ‘Sheerwater Seedling’
Size: Small
This selection is a fairly narrow, upright form with ascending branches. Its compact habit makes it a more formal choice than the species, which is more open and variable. Great for small scale formal avenues, and street planting.
Speciality:
Tilia cordata ‘Streetwise’
Size: Medium / Large
A tree cultivated and introduced by Hillier, has exceptional tolerance to periods of drought and heat. It has a strong central leader and well balanced crown, and being largely aphid free does not suffer from the problem of honeydew. As a result it is ideal for car parks, streets, and avenues. It is favoured for its robustness and excellent form.
Speciality:
Size After:
