Visual merit is an overall measure of the suitability of the sward for its potential use. Visual merit is a combination of sward density, leaf width, disease resistance, colour and other factors which could influence appearance such as cleanness of cut.
In most applications of amenity grass a dense sward is required, especially when a uniform and true surface is needed, such as golf greens. The number of shoots per unit area is assessed to give a measure of sward density of the sown species.
The live ground cover is regarded as more important than shoot density in winter sports turf. The ground cover of the sown species is recorded monthly during the application of artificial football wear to determine wear tolerance.
Mowing accounts for the majority of the cost of maintaining amenity grass. During the growing season (April to October) the sward height is measured immediately prior to each cut.
The leaf width of different varieties of grasses varies, especially for perennial ryegrasses and smooth-stalked meadow-grass. Fine leaves are desirable in fine turf and ornamental lawns. This assessment is not undertaken for Chewings fescues, hard & sheep’s fescues, slender creeping red fescues or strong creeping red fescues where there is little difference among these fine-leaved grasses.
Trials are monitored for differences in cleanness of cutting among cultivars. If differences are seen each variety will be scored for cleanness of cutting.
At a time when the usage of pesticides and the products available for use on amenity grasses are declining, disease resistance is of ever increasing importance. All trials are monitored for disease and scored when significant disease infections occur.
Cultivars are assessed for genetic colour in both summer and winter. This is a relative assessment with scores indicating how light or dark a grass is compared to the other varieties in trial. Lower numbers indicate a lighter coloured grass, higher numbers a darker coloured grass. It should be noted that colour will vary depending on weather conditions, management, and fertiliser use.
The winter sports turf trial is scored for two months following the application of artificial football wear to give an indication of individual varieties ability to recover from wear. Higher scoring varieties are less likely to need intensive renovation in the closed season.
The seed merchants listed below are primary agents for grasses listed in this booklet. Short codes have been given so that the grasses listed in the different tables can be cross-referenced with their suppliers.
Names and addresses of other breeders and suppliers, with only a restricted number of varieties in the booklet, are available from the BSPB.