ABSTRACT

New tree and shrub plantings around and in mown grasslands reflect the prevailing fashion in landscape design. One of the major factors controlling the composition of the grassland is whether it is sown or turfed or develops only though natural colonization. In warmer climates plants are likely to transpire more and growth could be limited by soil water availability so the increased temperature may or may not enhance their growth. Extreme soil compaction is common on demolition and construction sites, and the most fertile soils in their natural state, such as clay loams, can become the most hostile to plant growth and to some soil fauna, once denatured. Pockets of redistributed topsoil from other sites can bring propagules of persistent perennial garden weeds that spread from root fragments such as nettles, couch grass, ground elder, and horsetail or even Japanese knotweed.