Planting RequirementsSuccessful planter design begins with understanding the planting requirements – questions to consider include: - What type of planting is proposed?
- Will the planter contain trees, shrubs or herbaceous planting?
- What soil volume is required?
- Is irrigation required?
- What maintenance regime is anticipated?
“Think about the plants first” risks sounding like a statement of the obvious, but it is sometimes overlooked. And this issue is, in truth, often more complicated than it may seem, as it links directly to the issue below – Planting Environment. Planting EnvironmentEven if the general planting requirements are fully understood and considered, even more care often needs to be given to thinking about the planting environment. Domestic gardens can vary, of course, in terms of environmental conditions – but this tends to be at the margin. So the environment in a garden in Newcastle will be different from one in Cornwall, and that may well influence marginal decisions on issues such as plant selection etc. But they are both gardens, at ground level, in the UK; and they are both most likely reasonably sheltered, and – crucially – loved and cared for. By definition, a lot of commercial planters are in places where the plants would rather not be, if given a vote. Successful design and specification of commercial planters requires careful consideration of the planting environment, and the development of mitigating strategies to give the trees and plants the best chance of development. Commercial roof terraces present a particularly significant set of environmental challenges – see Roof Terrace Planter Design Guide. Structural LoadingCommercial planters can impose substantial loads, particularly when housing trees. This becomes especially important where planters are located on: - Roof terraces
- Podium decks
- Bridges or overpasses
- Suspended structures
Weight assessments should consider the fully installed and saturated conditions rather than the empty planter alone. And, for larger tree planters, the growing medium and retained water frequently account for the majority of the total load. For more detailed discussion of weights and loadings, plus some weight estimating guidance, please see: Tree Planter Design Guide. | Drainage and Irrigation IntegrationAlthough drainage and irrigation systems are often designed by specialist contractors, the planter must accommodate these requirements. Typical considerations include: - Drainage layers
- Reservoir systems
- Overflow arrangements
- Irrigation pipework
- Maintenance access
As already discussed, detailed design integration and contractual integration – from the outset – is often required to avoid conflict, and to ensure the long-term success of the commercial planter installation. Access and InstallationOne of the most frequently overlooked aspects of commercial planter design and specification is installation. Questions that should be resolved include: - Can the planter reach its final location?
- Is crane access available?
- Are there restrictions on component size [for example, what is the size of the service lifts?]
- Will sectional construction be required? Designing large scale planters in multiple sections.
- How will installation affect the project programme?
In many urban developments, access constraints become a defining design consideration. Ideally, these issues should be resolved within the specification documentation, but very often that is not practical [such as on a new-build development]. However, at the very least, all of these issues must be resolved before final Status A Shop Drawings approval. In addition to installation. IOTA offers a full suite of site works services – such as levels surveying, and on-site product templating – which can inform design before Status A approval. Long-Term MaintenanceCommercial planters should be designed with long-term maintenance in mind. Again, it is not always practical to address this at the conceptual design and specification stage. However, again as with installation, these issues really should be resolved before final Status A Shop Drawings approval. In the majority of commercial landscape schemes, long-term maintenance will fall within a plant maintenance contract – with the contractor being made responsible for the long-term development and survival of the trees and plants. Different plant maintenance contractors have different points of view – and use different systems for [say] irrigation. So, wherever possible, IOTA advocates that the plant maintenance contractor be appointed before designs are Status A approved, so that the contractor can contribute to the design. |