Open bottom planters in Corten steel

Specifying Planters for Public Realm and Civic Spaces

Creating Landscapes That Support Placemaking, Regeneration and Community Use

Most commercial planters are specified to improve a building or its setting. Public realm planters are usually specified for a different purpose. A town square, a regenerated high street, a transport hub or a civic plaza is not generating rent or direct income — the landscape is there to support wider objectives such as footfall, regeneration, civic identity and public amenity.

This has practical consequences for specification, which is affected by who is funding the scheme, who is responsible for its upkeep, how secure the maintenance budget is over the life of the asset, and the level of unsupervised public use the landscape needs to withstand. This guide sets out what public realm and civic landscape is generally intended to achieve, and what that purpose means in practice for specifying planters, trees and integrated features such as seating.

What Is Public Realm?

Public realm covers the outdoor spaces that the public can use freely, day to day, whether or not they’re technically owned by a council or other public authority. In practice that means places like town squares, civic plazas, streetscapes, transport hubs, waterfronts, university campuses, cultural destinations, parks and the public-facing spaces around mixed-use developments.

The common factor is not ownership but use. These spaces are unsupervised and open to anyone, and they are typically used by people with very different purposes at the same time – pedestrians passing through, visitors stopping to sit, and contractors needing access for servicing and maintenance. The landscape has to accommodate all of these uses simultaneously, without intrusive control over who is using the space at a given time.

Why Do Clients Invest in Public Realm?

Almost never for income from the landscape itself. The case for investment is usually built on what wider benefits landscape can deliver:

  • Placemaking and civic identity – giving a town centre or a new development a sense of somewhere, rather than just a route through it.
     
  • Regeneration – public realm spending is often the visible, first phase of a wider regeneration scheme, intended to change how an area is perceived before the rest of the investment follows.
     
  • Footfall and local trade – an attractive, comfortable street brings people who then spend money in the shops, cafes and businesses along it.
     
  • Dwell time – encouraging people to remain in a space rather than simply pass through it, which is generally regarded as a key measure of a public realm scheme’s success.
     
  • Wellbeing and public amenity – access to greenery and somewhere to sit outdoors, particularly in dense urban areas where private gardens aren’t an option.

None of these benefits represent a direct return on the landscape budget. They are measured through indicators such as business rates, footfall, property values, planning approval and public satisfaction, which are linked to the landscape only indirectly. As a result, the business case for public realm investment is often harder to establish, and harder to defend over time, than for landscape in a commercial development, where the link to income is either more direct, or the landscaping is required to satisfy a specific commercial or planning condition.

Who Are the Stakeholders?

Public realm projects usually involve more parties than a typical commercial scheme, and they rarely all want the same thing from it:

Local authorities generally want a scheme that looks good at opening, survives on a tight and uncertain maintenance budget, and doesn’t generate complaints.Developers contributing to public realm as part of a planning obligation usually want to meet the requirement at reasonable cost, while still getting some direct benefit for their own development.Regeneration agencies are usually working to a funding deadline and a set of outcomes they have to demonstrate to whoever provided the money.Transport authorities care about pedestrian flow, safety and not introducing anything that obstructs maintenance of the infrastructure underneath the space.Universities and cultural institutions tend to want landscape that reinforces their own identity and gives prospective students or visitors a strong first impression.


These priorities are not inconsistent with one another, but they do not necessarily align, and the specification has to satisfy all of them.

What Makes Public Realm Different to Specify For

A small number of factors distinguish public realm specification from most other landscape work, and they recur consistently across projects.

Capital funding and maintenance funding are usually separate, and are rarely agreed by the same people at the same time. 

A regeneration scheme is often funded through a one-off capital grant. Ongoing maintenance then has to be funded from a separate revenue budget, sometimes managed by a different department or a different organisation, and this is not always agreed at the outset. Maintenance budgets are also more likely to be reduced over time than capital budgets are to be cut once committed. In practice, this means the standard of maintenance a scheme receives in its first year is not a reliable guide to the standard it will receive ten years later, and specification should assume the maintenance regime may decline rather than remain constant.

Damage and misuse should be treated as routine rather than exceptional.

Public realm landscape is subject to a higher level of impact, wear and occasional vandalism than equivalent landscape in a supervised or privately managed setting. This should be treated as an expected condition to design for, not an exceptional risk.

Approval typically requires sign-off from multiple parties rather than a single client.

Highways authorities, planning, relevant utility companies, and in some cases conservation officers, environmental health officers or adjoining landowners, may all need to agree before a planter is installed on a public street. This generally extends the approval process compared with a single-developer scheme, and favours specifications with an established track record over novel detailing, since more parties need to be satisfied with the level of risk involved. On one Oxford student accommodation scheme, tree planters were specified as a planning condition for visual impact mitigation; and IOTA worked with the landscape architects Nicholas Pearson Associates for three years on this scheme, as it passed through its various stages from conception, to planning, to structural evaluation, and through complex approval processes with the University. Realistic timelines for multi-party sign-off of this kind needs to be built into the programme from the outset.

The use of the space is likely to change over its lifespan, often more than once. 

A space designed for one purpose may later be required to accommodate markets, events or activities not anticipated at design stage. Fixed, immovable landscape can restrict this kind of adaptation in a way it would not in a private scheme with a stable and predictable use.

What This Means for Specification

Each of the factors above has a direct bearing on specification.

Durability

Public realm planters need to be specified for continuous, unsupervised public use from the outset. This generally requires thicker gauge metal, additional internal bracing, and more robust detailing than an equivalent commercial planter of similar appearance.

Vandal Resistance

Materials and finishes need to cope with everyday knocks and occasional deliberate damage without looking tired within a year. Corten steel performs particularly well here, because a scratch or scuff simply re-patinates rather than showing as bare metal; and if graffiti is particularly egregious, then the entire piece can be sanded back to a uniform pattern, and the Corten will ‘self-heal’ in the normal way. See Corten Steel – The Facts and the Unique Benefits. For powder coated planters, anti-graffiti paint formulations are available, and are often specified.

Security

Planters are also routinely used to define pedestrian-only zones and manage traffic flow at the boundary of a public realm scheme. One such project example is this Snowhill Three, Birmingham where 23nr. large, massively constructed planters were used to form a green protected walkway between Snowhill Three and the extremely busy Queensway road system.

At the more demanding end of this topic, some schemes require planters to function as PAS 68 hostile vehicle mitigation [HVM]. This is a separate, certified product category, and a specialist area in its own right. A PAS 68-rated planter has to be engineered and tested as a security product first, with the planting function secondary to that; and, except for very large schemes, the cost of certifying a novel PAS 68 planter design is rarely warranted. More commonly, an existing, certified PAS 68 bollard is specified, and a planter is designed around it for purely aesthetic reasons – as here: PAS 68 bollard planter.

Tree Planting

The most common rationale for specifying planters for public realm, is because they allow planting to flourish in densely paved areas where underground utilities or shallow soil depths prevent standard ground excavation.

Trees – rather than shrubs or seasonal planting – are a particular challenge in public realm, as they are subject to the same soil volume, drainage and establishment requirements as any other tree planter, but with less certainty over the long-term irrigation regime. Where this is uncertain, it is generally advisable to specify more resilient species and more generous soil volume than the minimum required under ideal maintenance conditions, and to always include the largest possible internal water reservoir. See our Tree Planter Design Guide for more information and guidance.

Integrated Features

Seating, lighting, screening, public art and wayfinding are commonly integrated with public realm planting. The design coordination required is the same as in other sectors, with the additional requirement that each integrated feature is likely to need sign-off from more than one stakeholder. See Adding Seating to Planters and Illuminated Planters.

Maintenance Access

Drainage outlets, irrigation controls and tree anchoring points need to remain accessible to whoever is responsible for maintaining the scheme. In public realm contracts this is often a council contractor with limited time allocated per site, rather than a dedicated landscape team, and the specification should be designed around that level of maintenance access rather than an idealised one.

Flexibility for Events and Future Change

Where there is any prospect of the space needing to be cleared for markets, events or future reconfiguration, this should be addressed through specification rather than design intent alone. Building lifting or moving provision – typically forklift channels – into the planter at the manufacturing stage does add to cost, but retrofitting this provision once a heavy planter is already in place is significantly more expensive. See Moving Planters with Pallet Trucks or Fork Lifts and Moving Planters with Castors [although castors are rarely used in public realm, except in some specific circumstances such as Planters for Restaurants and Outdoor Dining Areas].

Designing in lifting or moving provision can also be justified where planters sit on top of buried services, such as a water mains. Although it is not IOTA’s call to make, we would suggest that the money be saved; for the simple, pragmatic reason that if a water main does indeed burst, the last thing on anyone’s mind will be to find a forklift or telehandler to try and save the planter.

Real Experience – Featured Projects

Public realm and streetscape is IOTA’s largest industry sector, and at the time of writing there were over 60 relevant project articles on our website. 

So these featured projects are just a small selection of what can be accessed in the Projects section.

At City of London Corporation, Cursitor Street, part of the Chancery Lane Area Enhancement Scheme, planters up to 8.4 metres in diameter were specified in 4.0mm Corten steel with an open-bottom perimeter construction, internally reinforced and fastened to concrete foundations to suit a high-traffic public realm setting.

Open bottom planters in Corten steel
City of London Corporation, Cursitor Street,
View project

At Snowhill Three, Birmingham, 23 large planters spanning 55 metres along Queensway were built in 3.0–4.0mm steel to provide protective screening between the development and a busy road. Podium-level planters elsewhere on the same scheme incorporated recessed lighting, illustrating how the same project can require both protective and amenity-led specification within a single installation.

bespoke planters for business district development
Snowhill Three
View project

At Stockton-on-Tees town centre and Darlington Market Square, both town centre greening schemes, forklift channels were built into the base of every planter, allowing the respective councils to reposition or remove the planters for markets and events as required.

Town centre public planters
Darlington Market Square
View project

128 movable planters were supplied for Bloomberg’s European headquarters, located in the heart of the City of London, close to the Bank of England and St. Paul’s Cathedral. IOTA’s planters were commissioned for the ground level hospitality and civic spaces, under and around the Bloomberg building, known as Bloomberg Arcade.

Outdoor perimeter planters for Bloomberg London
Bloomberg
View project

IOTA was commissioned to design and manufacture large bespoke Corten Steel planters for an extension to the Edinburgh Trams network. The order was for 59nr. planters of dims. L 2500 x W 950 x H 950mm, manufactured from 3.0mm Corten Steel, supplied pre-weathered. The planters are used to green the streetscapes at the new tram stations – running 4.7km northeast from the city centre at Princes Street, all the way to the Ocean Terminal and the final destination stop of Newhaven.

Large corten planters for street spaces
Edinburgh Trams
View project

Nearly 80 Coral Red planters were supplied to The Grosvenor Estate for North Audley Street, in the heart of Mayfair, London W1. The planters are laid out in clusters and rows along the length of the street, with drought-tolerant planting by Alexandra Noble Design.

coral red street planters in Mayfair
North Audley Street
View project

Need Help Specifying Landscape for a Public Realm or Civic Scheme?

Every public realm scheme has its own combination of stakeholders, funding constraints and long-term maintenance requirements. If you are developing a public realm or civic planter specification, we are always happy to review drawings, discuss practical options and identify opportunities to improve long-term performance and deliverability.

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