Spending cuts continue to have an impact on the horticultural industry, so landscaping schemes have to offer something more than aesthetic qualities alone. Architects and designers are well used to recommending plants that are either sustainably grown, that benefit biodiversity or are good for air quality. But there is also a practical level that should not be ignored.
Soft landscaping is a particular problem for large commercial and local authority projects. Following the not insignificant initial costs of the groundworks, procurement and planting, the client is generally required to find an annual budget for ongoing maintenance. With many controllers of the opinion that a maintenance budget should be set to zero, it is easy to see why during times of financial restraint, plant specification is often one of the first things to be cut from a scheme.
This has been noticed by Alan Standring, director of Greenline Plants. "Our landscape customers, which represent 98 per cent of our business, have many more smaller schemes and domestic work than they used to," he says. "They clearly have far less in the way of council work, so they are seeking more smaller contracts."
The type of work is changing, and so too are the kinds of plants being specified. Standring says: "We have seen a downgrading of plant specification, away from the unusual and exotic, towards the reliable and generally hardier stock."
So to encourage the continued - and increased - use of soft landscaping, which plants should architects and designers be specifying? Which plants are reliable but reduce maintenance costs?
Trees in the landscape have enormous cultural and environmental importance. Experts agree that they are the most important plant group for improving quality of life - by removing pollutants, reducing noise, providing shade, lowering ambient temperatures, housing wildlife and ultimately increasing land value. These benefits should be sufficient to encourage the increased use of trees in new schemes, but if the vexed question of maintenance arises, you would do well to choose mature specimens.
Although mature trees initially cost more, Civic Trees sales manager Deric Newman believes that they actually reduce the cost of maintenance in the long term: "If a scheme uses small trees, a year-on-year maintenance scheme needs to be in place for them to establish properly. But mature trees have had their formative training done in the nursery, so they considerably cut ongoing maintenance costs. They also have a greater resistance to vandalism."
He adds: "There are many other reasons to include mature trees: they offer immediate impact in the landscape, especially desirable where new developments are being introduced. And they offer a more positive feeling to the landscape. Their physical size and scale give a design an instant feeling of establishment."
Low-maintenance trees include:
- Magnolia (Magnolia x soulangeana). No pruning necessary.
- Pagoda tree (Sophora japonica). No pruning necessary.
- Pine (Pinus heldreichii AGM). Pruning is seldom necessary.
- Hawthorn (Crataegus laevigata 'Paul's Scarlet' AGM). No maintenance required.
Multistems are another option for specifiers. They may have begun as a Continental trend, but they have become mainstream in UK fashion. Chartered landscape architect Jane Findlay of Birmingham-based Fira Landscape has experience of large and complex developments for both the public and private sectors, including the master planning of the 121ha National Memorial Arboretum in Staffordshire.
"If vandalised, a multistem would not be completely ruined, unlike a single standard," she says. "They also need less securing than their single-stemmed counterparts because they are more able to withstand wind. Cheaper species, such as alder and silver birch, give good in-fill."
Good multistems include:
- Ash (Fraxinus excelsior 'Jaspidea' AGM). Wind-tolerant, fairly fast-growing.
- Mountain ash, rowan (Sorbus aucuparia). No pruning needed.
- Tibetan cherry (Prunus serrula). Ornamental peeling, shiny stems.
- Silver birch (Betula pendula). Grown for its bark and autumn colour.
Hedging and screening
Although hedges require more annual maintenance than a brick wall, fence or even a tree, the rewards in terms of aesthetics and habitat mean that they are a valuable form of planting in the landscape.
As with mature trees, it could pay dividends to opt for pre-formed hedging. Tendercare Nurseries design director Margie Ribton says: "For suburban settings, trimmed 'instant' hedging isn't really that expensive and there's no fuss about working out spacing. People want maturity and this is the solution."
Kent-based Wyevale East Nurseries Plant manager Nigel Gibson adds: "It is the slower-growing hedges that tend to need least clipping. Buxus and Taxus both make perfect hedges that need to be cut just once a year, but they are relatively expensive."
Europlants sales manager Mark Smith suggests Ligustrum japonicum 'Texanum'. "This is a great evergreen plant that has dark glossy leaves," he says. "It is hard and available as evergreen trees and large shrubs. It tolerates a maritime exposure and is a good alternative to Elaeagnus or Griselinia."
Other worthwhile low-maintenance hedging includes:
- Cornelian cherry (Cornus mas). Trim once a year in late spring.
- Mountain currant (Ribes alpinum). Trim once a year in late spring after flowering.
- Evergreen spindle (Euonymus japonicus 'Green Rocket'). Trim once a year in late summer.
- Spiraea (Spiraea japonica). Trim once a year after flowering.
These are frequently the main stumbling block for plant specifiers when it comes to ongoing maintenance costs. Many shrubs are actually high maintenance, needing three or four cuts a year in some cases.
Smith recommends Prunus cerasifera 'Pissardii'.
"This can be used as a large shrub or a small deciduous tree," he says. "Its purplish-blue branches are covered in pink flowers in early spring. The leaves are oval and reddish-purple. Planted as an individual shrub or as a deciduous hedge, it is available commercially in sizes up to 4m. As a tree, it is available up to a girth of 30-35cm." He also favours Drimys aromatica, "a very attractive evergreen shrub with white star-shaped flowers in March and April".
Other easy-care decorative shrubs include:
- Common hawthorn (Crataegus monogyna). No pruning necessary.
- Sea buckthorn (Hippophae rhamnoides AGM). Trim once a year in mid to late summer.
- Buffalo currant (Ribes odoratum). Prune once a year in late spring after flowering.
- Elaeagnus ebbingei 'Vivileg'. Variegated leaves that do not revert so readily.
Bamboos and grasses
If you want to provide virtually maintenance-free texture to a roundabout, to lighten up a dull, low-nutrient woodland or achieve a dramatic contrast within a herbaceous border, grasses are a good choice. And they come in many shapes and sizes.
Gibson says: "The only major maintenance many grasses demand is to pull off the flower stalks at the end of winter and cut back the foliage once every five years. This, along with their natural sturdiness, makes them excellent for large-scale schemes and for municipal plantings where the cost of upkeep is constantly under scrutiny."
Tall grasses and bamboo create atmospheric Spanish-style screens, but choose carefully as many species are invasive. Smith reckons we are safe with Phyllostachys aureosulcata f. spectabilis AGM. The following four easy-care grasses all require splitting after three or four years:
- Carex (Carex oshimensis 'Evergreen').
- Festuca (Festuca mairei).
- Pennisetum alopecuroides 'Moudry'.
- Switch grass (Panicum virgatum 'Rubrum').
Roses make a municipal comeback
Roses fell out of favour several decades ago because of their reputation for being difficult to maintain. But things have improved.
David Austin Roses technical manager Michael Marriott says: "Enlightened designers are glad to use roses in a variety of municipal situations and maintenance does not always have to be a problem. Take ground cover roses, for example. These are an ideal solution for roadsides and banks. They have a great spread of colour, repeat flower and have been bred for disease resistance."
Pruning is not the labour-intensive process it used to be. Many roses have been bred for vigorous growth that does well after a shearing (on larger schemes, a mechanical flair or reciprocating bar trimmer works very well).
Marriott adds: "Roses offer structure in the winter and if the right variety is used they have a long flowering season. They are also great for security because they are vandal proof. Unless vandals have a very good pair of gloves, they are unlikely to pull up the roses."
Austin's English roses are useful where low maintenance is important. They do not need to be pruned back every spring and so flower earlier. If pruned, they become sturdier.
Designers should also consider the apothecary's rose (Rosa gallica var officinalis) Award of Garden Merit (AGM), Father Hugo's rose (R. xanthina f hugonis AGM) and R. multiflora. None of these need regular pruning, but can be thinned in late winter if needed.