A border outside the car park has recently be renewed by the garden team. The existing planting and the top layer of soil was removed.
Rather than use a nutrient-rich topsoil, which invariably contains weed seed, approximately 30cm (12 inches) of locally sourced sand and gravel was added to the area. This weed-free planting aggregate will naturally dry out and form a crust on the surface, making it difficult for weeds to establish. Deeper down, the mixture retains moisture. The plants have been chosen to thrive in these conditions and, although initial growth will be much less than if the plants were planted in a rich soil, they will establish without the need for constant watering and weeding.
Like the Gravel Garden, the border will not be irrigated (the plants were watered in, but will now have to survive on whatever rainfall we receive). The sand makes it low-maintenance in comparison with the Gravel Garden, where the gravel mulch acts as a perfect germination ground for seeds. It's also easier to remove unwanted plants from the sand.
List of drought-tolerant plants used:
We haven't found ants to be a big problem. Perhaps it's because we use ungraded sand (a mixture of particle sizes) so maybe the ants prefer a more soil-like structure? We shall keep an eye out and report back!