What is the best plant for hedging and topiary?

 A Potted History

Ancient. Spiritual. Toxic. The King of hedging.

If the title didn’t already give it away, the keen gardeners and botanists out there will have probably guessed I’m talking about English Yew aka Taxus baccata (it’s Latin botanical name). Perhaps the longest-lived species of native tree in Europe and one of only three species of conifer (including Juniper and Scots Pine) which are generally recognised to be native to Britain. It is extremely likely that you will encounter this beautiful plant regularly. Yew is widespread and common to spot whilst out and about in the UK, whether it be in woodland, on a historic country estate, used as domestic garden hedging or the as the huge guardians of churchyards, where some specimens are thought to be older than the church building themselves. If left to their own devices Yew can expect to live for around 900 years before it becomes ancient, compared to 400 years for an oak tree. The Fortingall Yew in Perthshire, Scotland is thought to be between 3,000 and 9,000 years old and is believed to be one of the oldest living things in Europe. It is often difficult to put an accurate age on ancient specimens due to their incredible ability to regenerate, producing fresh shoots from apparently dead wood. To make it trickier, their trunks rings (the concentric rings in the cross section of a tree trunk, each one representing a single year’s growth) cannot be counted or carbon dating cannot be undertaken on most Yews because their ancient hearts rot and disappear sometimes leaving hollow centres. This great talent for regeneration gives the plant a very mystical history and makes them excellent subjects for eccentrically formed topiary and formal hedging which I will talk about in more detail later.

Yew has long been met with a mixture of admiration and fear holding a myriad of deeper meanings in folklore and religion. It was believed in times past to protect and purify the graves of the dead and was a symbol of immortality due to its ability to regenerate, boasting stories of stems sprouting from the staffs of holy men or from beams within buildings. Yew timber is extremely strong and durable. In fact, one of the world’s oldest wooden artefacts is made from Yew; a spearhead found in Essex, dated at 450,000 years old. The hard, close-grained yet flexible wood was traditionally used to make tool handles but is perhaps best known as the main material for the formidable and deadly Medieval longbow where once upon a time, whole plantations of yew trees were carefully cultivated for their manufacture. Today the timber is still popular for bows, wood turning, cabinetry and veneers.

Identification

If you are not sure how to identify Taxus baccata look for an evergreen plant (which has green foliage throughout the year) with very dark green, small, straight needle shaped leaves with a pointed tip, growing in two rows along the stem. The bark is a peeling reddish-brown with purple undertones. Yew trees are dioecious, meaning that male and female flowers grow on separate trees. Male flowers are insignificant white-yellow globe-like structures, whereas female flowers are bud-like, scaly, and green when young becoming brown and acorn-like with age. In March and April, you will see them covering the tree canopies which billow with clouds of dusty pollen in the wind.

Although Yew is classified as a conifer, it does not produce seed in cones like it’s relatives. Instead, each small dark brown pip like seed is enclosed in a deep red, fleshy, berry like structure with an open hole in the tip, known as an aril. The red flesh of the ripe aril is the only nontoxic part of a Yew and a good food source for birds, small mammals and even deer who know to avoid the seed or cannot physically digest it. Instead, they help to disperse it through their droppings. It is also edible to humans however I do not recommend this due to the potentially fatal consequences if the seeds were also accidentally consumed. The seed enclosed in the centre of the red berry is deadly poisonous when digested, as indeed are all other parts of the tree. When I think of the Latin name ‘Taxus’ I am always reminded of the word toxic with a bright red ‘X’ however the word refers to the highly poisonous ‘taxane alkaloids’ found in the needles and bark. But even this frightening fact cannot be held against the magnificent Yew tree. In the words of Paracelsus, who expressed the classic toxicology maxim “All things are poison, and nothing is without poison; the dosage alone makes it, so a thing is not a poison.”, it has been discovered that these alkaloids play a very important role in modern medicine and have been developed as anti-cancer drugs. They are used in the chemotherapy drug Taxotere® (docetaxel), which has proven effective in combating lung and prostate cancer and advanced cases of breast cancer.

Garden Uses

There are so many reasons to use Yew in your garden and at Bestall & Co it is one of our favourite plants to include. It’s dense yet fine, deep evergreen foliage provides the perfect backdrop for other plants, making colours pop. It’s calming green presence remains all year adding valuable interest in the bleak winter months as well as adding important structure to define different areas in garden and create focal points; it also looks fabulous in planters.

Taxus baccata has been widely used in garden design and horticulture for centuries. Yew is reliable, tolerant, and long-lived, often the main survivor from earlier phases of historic gardens and can be widely admired in many forms in public gardens throughout the country. Renishaw Hall Gardens has a bountiful number of immaculately pruned Taxus hedges which create romantic, Italianate style garden rooms. Powis Castle’s famous Yew ‘tumps’ are almost 300 years old, and their unusual organic shape tells a story of the changing tastes in horticulture though history.

Yew can be acquired from specialist nurseries in a variety of sizes and forms – from balls to pyramids, mushrooms to spirals, which all bring instant impact to the garden. It can simply provide screening or a hedge from as low as 1m to 4m tall if left to grow. It can be quite pricey, especially sizes over 80cm tall that are delivered as rootballs and this is due to the time and level of care taken to grow specimens of that size. Even so, mature specimens and instant hedging can be a great investment, adding powerful structure and maturity to a garden. If budget is restricted then buying smaller, bareroot specimens and waiting for them to grow to their intended final size is a good alternative but this will require patience and quite particular pruning.Mature yew trees can grow to whopping 20m height and 10m spread creating a fabulous specimen tree, but equally lend themselves perfectly to low formal hedging or topiary due to their dense bushy habit when clipped, as well as being manipulated into unusual shapes and curves, including cloud pruning. Yews regenerative power means existing specimens or overgrown hedges can be restored and reshaped with hard pruning and a little patience which can also be good for your wallet and the local environment. As it is a native plant, it has great value for wildlife providing food, shelter, and nesting sites.

Cultivars

It is no co-incidence that Taxus bacatta has held the RHS Award of Garden Merit for 20 years! There are currently over 200 named cultivars of Taxus baccata. ‘Cultivar’ refers to a plant variety that has been produced in cultivation by selective breeding from a natural species but but does not produce true-to-seed.

The most popular of these is arguably the Irish Yew (T. baccata ‘Fastigiata’), a fastigiate cultivar (having the branches more or less parallel to the main stem) selected from two trees found growing in Ireland. An Irish Yew can reach 6m in height without exceeding 60cm in diameter at its thickest point, although with age many Irish Yews assume a fat cigar shape rather than being truly columnar. The size and shape of the tree can be controlled by careful clipping, but this must always be done sparingly. Very old specimens may develop outward bending branches which need to be secured with wire; almost forming a corset or cut off. Irish Yews make wonderful architectural additions to the garden as pillars within planting, the centre of knot gardens or repeated against a wall to create contrast, symmetry, and height.

1. baccata‘Repandens’ is a lesser known but equally robust, spreading cultivar of English Yew. It greatly resembles the native dark green Yew in foliage appearance, but rarely produces berries and has a very different growth habit – lateral rather than vertical, making it perfect for ground cover. After 10 years of growth a mature specimen will measure 60cm tall and 2m wide. T.’Repandens’ can also be used as low formal hedging when pruned regularly or shaped into organic forms.

There are several Taxus baccata cultivars with yellow leaves, collectively known as ‘golden yew’ which includes T.baccata ‘Semperaurea’ and T. baccata ‘Fastigiata Aureomarginata’ (golden Irish Yew). Although not currently ‘on trend’ in the design world, perhaps because of their association with dated 1960’s rockeries, golden yews do have a place in planting design. The new knot garden at Thornbridge Hall, Derbyshire is a great example of a contemporary take on golden Yew, partnering both fastigiate and hedging varieties with soft Stipa grasses and purple flowering Salvia and Verbena for great colour contrast. The impact is quite stunning.

 Care

Taxus will tolerate a wide range of soils and situations, providing it is well drained – including shallow chalk soils, exposure, dry soils, urban pollution, full sun, and shade (in deep shade the foliage may be less dense). However the one condition it will not endure is water-logging, and in poorly-draining situations it is prone to succumb to the root-rotting pathogen Phytophthora.

Yew will appreciate an annual feed of organic fertiliser (Fish, Blood and Bone is good) as well as annual mulching with a soil improver to prevent weeds and add nutrients to the soil. Apply both in early spring for optimum growth. Feeding is always necessary for Yew in planters. A controlled release all round fertiliser is best for this job, such as ‘Osmacote plant food tablets’ which cover the entire growing season if inserted in February and last for 6 months.

Although Yew is labelled as a slow growing plant, when newly planted and unpruned, young specimens can put on 40cm of growth a year – more if it is well cared for and growing in ideal conditions. Yew will begin to grow slowly when the growing tips of the central, leading stems are cut.

With a new immature hedge that still has quite a lot of growing to do, refrain from cutting the top off if it has not reached the intended height, as this will reduce the speed of growth from around 40cm a year to 10cm a year. Once the hedge has reached the desired height, allow for 10cm more growth than the intended and lightly prune at any time except in freezing weather. In the early years, the more often you clip the side branches, the bushier your Yew hedge will become.

August to October is Yew hedge cutting season, leave the branches at the bottom of the plant just a little longer than the ones near the top, creating tapered sides. This allows light to hit the bottom of the plant and prevents bald, twiggy patches forming. Unlike many evergreen conifers, an established Yew plant is very forgiving and can be hard pruned if necessary, whereafter it will grow back with vigour. Should you wish to drastically alter the shape or height of your yew hedge (e.g. cutting an archway through it, or significantly reducing the height) carry out the surgery in mid-winter when the plants are semi-dormant. If you have an overgrown Yew hedge and you need to reduce its width, cut one side back very hard one winter, and reduce the other side the following year. If you have complex topiary, trim in June and/or late August.

If you have clay soil, don’t entirely write off the possibility of using Taxus in your garden. Yew needs a reasonably well drained soil to grow and clay soil can be well drained if extra drainage is installed. It does not like bogs, riversides or ground that holds water for long periods of time however, any soil that isn’t wet for most of the year and has a small amount of winter flooding is tolerated. When planting in clay soil do not dig a trench or hole and then backfill with topsoil which is the usual method of planting; this creates a sump for water to collect. Instead make a slit or small hole and back fill with the existing soil firming the roots in well.

Taxus can be difficult to establish and one of the most commonly asked questions is why is my Taxus turning brown?

First published August 2021 & revised June 2024