Specimen Tree Sizes Explained

Choosing the right specimen tree involves more than selecting a species and an overall height.

Nursery specifications can include trunk girth, clear-stem height, overall height, crown size, root type and tree form. Two trees described as being the same height can look very different and may require different delivery and planting arrangements.

This guide explains the terminology used across our specimen-tree collection and helps you understand what you are ordering.

Why Are Trees Sold by Girth?

Standard-form trees are usually graded according to the girth or circumference of their trunks.

Girth is measured in centimetres around the trunk, normally at approximately one metre above ground level.

A tree described as 12–14cm girth should therefore have a trunk circumference between 12cm and 14cm at the specified measuring point.

Girth is not the same as trunk diameter.

As the girth increases, a tree will generally have:

• A thicker trunk

• A more developed crown

• Greater overall maturity

• More immediate visual impact

• A larger and heavier root system

• More demanding delivery and handling requirements

• A higher purchase and installation cost

Tree girths normally increase in bands, such as:

• 8–10cm

• 10–12cm

• 12–14cm

• 14–16cm

• 16–18cm

• 18–20cm

• 20–25cm

• 25–30cm

Not every species is available in every girth.

What Does Overall Tree Height Mean?

Overall height is measured from the base of the tree to its highest growing point.

It includes:

• The clear trunk

• The crown or branches

• The leading shoot

Overall height should not be used on its own to judge the maturity or impact of a tree.

A slender, fast-growing tree may be considerably taller than a slower-growing tree with the same trunk girth. A broad-headed tree may appear more substantial despite having a lower overall height.

Always consider height alongside:

• Trunk girth

• Crown spread

• Tree form

• Clear-stem height

• Species and cultivar

• Rootball or container size

What Does Clear-Stem Height Mean?

The clear stem is the section of trunk between ground level and the lowest principal branches.

A standard tree will commonly have a clear stem of approximately 1.8–2 metres, although the exact specification varies according to the tree, nursery and product.

A clear-stem tree is useful where:

• People need to walk underneath the crown

• The tree is positioned beside a path

• Visibility beneath the crown is important

• Planting is required below the tree

• Screening is needed at first-floor height

• A formal tree-like appearance is preferred

Always check the listed specification rather than assuming that every standard tree has exactly the same clear-stem height.

What Is a Standard Tree?

The word standard describes the tree’s form rather than simply meaning a large tree.

A standard-form tree has a defined single trunk with a developed crown above a clear stem.

Depending on its girth and maturity, a standard tree may be described as:

• Light standard

• Standard

• Selected standard

• Heavy standard

• Extra-heavy standard

• Semi-mature tree

Nursery descriptions vary, so the stated girth and individual product specification are more useful than the descriptive name alone.

Standard trees work well for:

• Avenue planting

• Formal gardens

• Lawns

• Patios and seating areas

• Driveways

• Screening above fences

• Repeated structural planting

What Is a Heavy Standard Tree?

A heavy standard is a more substantial standard-form tree with a thicker trunk and better-developed crown than a younger standard.

Heavy standards provide greater immediate impact while remaining manageable for professional delivery and planting.

They are often selected where the client wants the garden to appear more established from the outset.

A heavy standard will generally require:

• A larger planting hole

• More substantial anchoring

• Careful handling

• Greater watering provision

• More delivery access

• A longer establishment period

The exact specification can vary, so use the girth range shown on the product rather than relying solely on the term “heavy standard”.

What Is an Extra-Heavy Standard?

An extra-heavy standard is a larger and more mature tree with a thicker trunk, more developed crown and heavier rootball.

These trees offer significant immediate presence but require more careful logistical planning.

Depending on the individual tree, installation may involve:

• Mechanical lifting

• Specialist delivery

• Restricted-access planning

• Underground anchoring

• Larger quantities of planting soil

• Irrigation

• More intensive aftercare

The garden entrance, gates, paths, steps and overhead obstructions should all be considered before ordering.

What Is a Semi-Mature Tree?

Semi-mature generally describes a well-developed tree intended to create an immediate landscape effect.

There is no single visual appearance shared by every semi-mature tree. The term can cover different girths and forms according to the species and nursery.

A semi-mature tree is likely to have:

• A substantial trunk

• A well-developed crown

• A large rootball

• Considerable weight

• Specialist handling requirements

• A higher watering requirement during establishment

Large size does not eliminate the establishment period. A semi-mature tree still needs time to produce new roots within the surrounding soil.

What Is a Feathered Tree?

A feathered tree has branches growing along much of the main stem, often from relatively close to ground level.

Unlike a standard tree, it does not have a long clear trunk below the crown.

Feathered trees are particularly useful for:

• Privacy screening

• Creating a dense visual barrier

• Boundary planting

• Wind protection

• Naturalistic planting

• Producing a fuller effect from lower down

The lower branches may be retained permanently or gradually removed as the tree develops, depending on the required result.

The product description should state whether a tree is fully feathered, lightly feathered or supplied with a particular branching specification.

What Is a Multistem Tree?

A multistem tree develops several main stems from or close to ground level instead of having one dominant trunk.

Multistem trees normally create a broader, more sculptural appearance than standard-form trees.

They are often used as:

• Garden focal points

• Courtyard specimens

• Features within planting beds

• Architectural trees

• Naturalistic woodland-style planting

• Trees viewed from inside the house

Multistem trees are commonly sold according to overall height rather than trunk girth.

The number, thickness and arrangement of the stems will vary naturally between individual specimens.

What Is a Bush-Form Tree?

A bush-form tree carries branches from low down and has a dense, full appearance.

The distinction between bush-form and feathered trees can vary between growers, so examine the complete specification and photographs where available.

Bush-form trees can provide useful low-level screening but generally need more width than clear-stem standards.

What Does Pleached Mean?

Pleached trees have branches trained onto a framework to produce a raised panel of foliage.

They are commonly used to create screening above a wall or fence while retaining a clear stem below.

A pleached-tree specification should include:

• Clear-stem height

• Frame width

• Frame height

• Overall height

• Girth or stem strength

• Root type

• Number of trees required

• Recommended spacing

Pleached trees need accurate positioning so that their frames align properly when planted.

Explore our specimen trees for privacy for more screening options.

Rootballed Trees

A rootballed tree is lifted from the nursery field with a ball of soil retained around its roots.

The rootball is normally protected with hessian and may also be supported with wire.

Rootballed trees are usually available during the dormant lifting and planting season. The precise season depends on the species, weather and ground conditions.

Benefits can include:

• Access to larger field-grown trees

• A wide selection of sizes

• Strong nursery-developed root systems

• Good value compared with equivalent container-grown specimens

The hessian and supporting material should be handled according to the planting specification rather than casually removed before installation.

Container-Grown Trees

Container-grown trees are cultivated and supplied in pots or rigid containers.

They can generally be planted over a wider part of the year, provided that:

• The ground is workable

• It is not frozen or waterlogged

• Adequate watering can be maintained

• Extreme hot or dry conditions are avoided

Container volume provides useful information but does not describe the tree’s complete size. Two trees in the same container size may have different heights, forms and trunk girths.

Bare-Root Trees

Bare-root trees are lifted and supplied without soil surrounding their roots.

They are generally available during the dormant season and are often smaller than the specimen trees supplied as rootballed or container-grown stock.

Bare-root trees can be cost-effective for woodland, native planting, orchards and some hedging applications. They require prompt handling and planting because the roots must not be allowed to dry out.

Does a Larger Tree Establish More Quickly?

Not necessarily.

A larger tree provides greater immediate visual impact, but it also has:

• A larger crown requiring water

• A heavier root system

• More demanding anchoring requirements

• Greater sensitivity to inadequate aftercare

• A potentially longer establishment period

A smaller tree may establish and begin active growth more quickly, although it will take longer to produce the same immediate visual presence.

The best size is the one that balances impact, budget, access, planting conditions and long-term establishment.

Choosing a Tree Size for Privacy

Where privacy is the main objective, overall tree height is only part of the decision.

You also need to establish:

• The height of the unwanted view

• The height of the lowest branches

• Whether screening is needed from ground level

• Whether a clear trunk is desirable

• Required crown width

• Spacing between trees

• Whether the foliage is evergreen or deciduous

• The likely mature dimensions

A 4-metre standard tree with a 2-metre clear stem will not screen from ground level. Conversely, a 3-metre feathered tree may provide much denser low-level screening.

Choosing a Tree Size for a Small Garden

In a smaller garden, choosing a very large nursery specimen does not change the tree’s eventual mature size.

Select according to:

• Mature height and spread

• Crown shape

• Rooting characteristics

• Distance from buildings

• Available light

• Maintenance requirements

• Relationship with neighbouring gardens

A smaller-growing species in a substantial nursery size may provide immediate impact without creating an unsuitable long-term tree.

Delivery and Access

Larger trees may require mechanical handling and sufficient access from the delivery vehicle to the planting position.

Before ordering, consider:

• Gate widths

• Narrow passages

• Steps and level changes

• Soft or unstable ground

• Overhead cables

• Buildings and covered areas

• Turning space

• Crane or loader access

• Distance from the unloading point

• Protection of existing paving and lawns

A tree may physically fit through an opening while its rootball, crown or handling equipment does not.

We may request photographs, measurements or a site assessment before confirming the installation of a large specimen.

Professional Planting

Our specimen-tree planting packages can include:

• Delivery

• Mechanical handling where required

• Ground preparation

• Planting

• Soil improvement

• Appropriate anchoring

• Stakes and ties

• Irrigation provision

• Mulching

• Initial watering

• Aftercare guidance

Professional planting is available throughout North West England, including Lancashire, Greater Manchester, Cheshire and Merseyside.

Looking After a Specimen Tree

Every newly planted specimen tree requires aftercare, regardless of its size.

The most important requirements are:

• Thorough watering

• Regular soil-moisture checks

• A weed-free root area

• Suitable mulch

• Monitoring of stakes and ties

• Protection from mower and strimmer damage

• Checking for movement after strong winds

• Prompt investigation of declining foliage

Read our guide to looking after newly planted trees and hedging before your tree arrives.

Frequently Asked Questions

Is tree girth the same as trunk diameter?

No. Girth is the circumference measured around the trunk. Diameter is the width through the centre of the trunk.

Does a 4-metre tree provide screening from the ground?

Not necessarily. A standard tree may have a clear trunk below its crown. Choose a feathered or bush-form tree where low-level screening is required.

Are multistem trees measured by girth?

They are usually sold primarily by overall height because several stems emerge from the base. Individual nursery specifications can vary.

What size tree can be planted without machinery?

This depends on the tree’s weight, rootball, access and distance to the planting position. Overall height alone does not determine whether machinery is required.

Is the tree’s advertised height exact?

Tree measurements normally represent a size range. Trees are living products and natural variations in height, crown shape and branching should be expected.

Which tree size gives the best value?

That depends on the required impact, access, species and budget. A moderately sized tree that establishes successfully may offer better long-term value than the largest possible specimen.

Find the Right Specimen Tree Size

Browse our complete range of specimen trees, including deciduous and evergreen specimen trees.

If you are uncertain about the correct size or form, send us photographs and measurements of the planting position. We can help identify an appropriate species, specification and planting package for your garden.