The geology beneath Cumbria is complex with everything from sedimentary limestone and sandstones to volcanic igneous and metamorphic slates and granites. The rock foundations affect drainage and the acidity (or otherwise) of the soil and will influence the stone types used in any garden design, usually echoing the house and garden walls as well as creating opportunities for features that will look established and “at home”.
Soil pH (the measure of acidity and alkalinity) can vary a lot over a short distance and will make a big difference to which plants thrive. The soil in a limestone area, such as South Lakes and Upper Eden, is alkaline whereas in slate areas, such as the Central Lake District around places like Keswick and Ambleside, the rock has volcanic origins and tends to be acidic. In sandstone areas, like those around Penrith and Carlisle, the soil is generally neutral. Given the complexity of Cumbrian geology, we always take pH measurements across a garden, just in case we’re on a border between different types.
Acidic or ‘sour’ soils lend themselves to ericaceous plants and most people think of rhododendrons. Liz’s favourites on slate include Hamamelis x intermedia ‘Jelena’, Fothergilla x intermedia ‘Beaver Creek’ and Pieris japonica ‘Katsura’.
In contrast, lavender and many herbs thrive in alkaline or ‘sweet’ soils. These are also ideal for Euonymus europaeus ‘Red Cascade’, Syringa ‘Carpe Diem’ and Berberis thunbergia ‘Orange Sunrise’.
If your garden design uses existing stone paving or reclaimed material then key decisions are clear.
“The emphasis is always on re-using existing stone that is on site or sourcing as locally as possible.”
However, for new paving and features, local quarries across the county can supply what you need. For instance, for the northern Lakes, that often means Honister Slate Mine with their distinctive green slate.
Imported stone can be a good substitution with associated cost savings. With any paving, it’s what goes on underneath that’s important – the right preparation of the ground and the final pointing, often resin-based these days, makes all the difference to durability. The skill is in choosing the right paving to complement the local stone walling.
There’s a saying about Right Plant, Right Place but Right Stone, Right Place is just as important. We are very fortunate to work with a variety of stone types as we design and build gardens all over the county – and that’s part of the Cumbrian challenge that we enjoy.