The best place to start is to work out the area of your garden (or part of it you want to work on) in metres², and go from there. There are three basic approaches: planting based, mixed, and predominantly hard-landscape. Obviously this is really a spectrum, and your garden will sit somewhere along it. Larger rural gardens will be more plant-based, suburban gardens mixed, often about 60-70% planting (including lawn) and 30-40% hard surfacing, and urban gardens, particularly smaller ones, may be up to 90% hard landscaping. Bear in mind that boundary treatments take up very little area in plan, but can incur significant costs – the most expensive options being walls and the cheaper options being fencing or hedging.
To budget for garden design, you need a clear idea of what you want to achieve with your garden, in terms of both functionality, aesthetics and maintenance. Be aware of the relationship between up-front costs and on-going (maintenance) costs. Hard landscape solutions often have high up-front costs but low maintenance costs, whereas planting may be less expensive initially, but requires ongoing maintenance. Labour is the biggest cost in all gardens, and if you are employing a contractor to undertake the work, the following ball-park figures are a good guide for budget:
Budget For Garden Design Costs By Area
- £40 – £65/m² for all soft-landscaped areas
- £100 – £150/m² for hard landscaped areas
- A rural garden with mainly planting can be achieved for £40 – £65/m²
- An average suburban garden, with some work to boundary treatment, often works out at £75-125/m². The overall cost will be very much affected by the ratio of soft to hard landscaping, along with issues such as ease of access.
- A city garden with high level of finish and mainly hard landscaping may cost from £150-400/m², especially in London where congestion charges and poor site access add hugely to construction costs.
How To Save on Garden Design Costs
Cheap materials often look cheap, but if you shop around and look at stone from different suppliers, cheaper options can be found. Porcelain paving can be a low-maintenance cost-effective alternative to natural stone paving. Perennial plants usually reach their mature size within 3 years, so if you can wait a while, buy plants smaller. Some trees and shrubs grow quickly when young whilst others are slow – so know your trees and select the right ones. Timber products – fencing and decking – vary hugely in price. Sometimes locating a local sawmill will be the best and cheapest option, and you will be supporting a local business, not the middle-man. If you don’t mind using recycled materials or plants, keep a saved search on eBay, or sign up with your local Freecycle group.
Allow For Contingencies
You should never use all of your budget on the projected cost. Allow for unforeseen expenses: a minimum 5-10%, but on steeply sloping and complex sites, allow 25%. If you don’t do this, a simple cost overrun (and they do happen) can ruin your chance of completing the garden as you wanted to. A garden where 10% has been held back for contingencies that runs over by 5% will look exactly as you want. A garden with no contingency that runs out of money 90% to completion will be far less satisfactory.