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Gardening in Coastal Conditions

With 422 miles of coastline, Cornwall hosts many coastal gardens, and Cornish gardeners have learned to cope with the challenges this brings. However, not all coastal gardens are the same. The sheltered valley gardens of the south coast bear no resemblance to exposed cliff top gardens blasted by Atlantic gales on the north coast.

The main problems are wind and salt spray, and shelter is of the essence. Many years ago we had a customer who retired to Cornwall and bought a bungalow with an established garden and wide sea views. He was disappointed that he couldn’t see the sea when he was sitting down in the house, so he removed two of the conifers in the boundary hedge. He could see the view but he let the wind in. The conifers either side of the gap became brown and scorched so he removed them too. He ended up with a good view from his chair, a spoiled hedge and a ruined garden.

Shelter can be provided on various scales, from massive tree belts, to hedges, fences, or even planting in the lee of a large shrub. A Cornish hedge is a traditional and effective shelter for plants and livestock. It is actually a thick stone wall, wider at the bottom and filled with earth, and may have hedging plants or trees planted on the top to increase its wind-breaking height. Ancient Cornish hedges develop a rich diversity of flora over their lifespan and it is gratifying to see that more are being built in current times. Semi-permeable structures which filter and reduce wind are most effective. A temporary windbreak such as mesh will help plants establish initially and can help a newly planted hedge get off to a good start.

Gardens on the south coast face different climate challenges, often being in mild and sheltered valley sites, virtually frost free and unaccustomed to howling gales. Some of these gardens have semi tropical planting and when a rare east wind blows, as in the Beast from the East in 2018, they can suffer significant damage. Others may not be in sheltered valleys but on the side of a cliff, or virtually on the beach. Here, as well as salt spray, plants must cope with soil which is little more than sand and stones, and shelter may only be a boulder. There can be no greater contrast than the seaward aspect of St Michael’s Mount and the sheltered ravine of Trebah, both gardens on the south coast.

Plants have evolved strategies for coping with adverse conditions. Leaves which are silver or grey, hairy, small, or have waxy cuticles will all help plants survive drought and salt spray, and being blasted by sand. Succulence and deep roots will also help with drought. Many have physiological adaptations enabling them to extract water from salty soil. A low growing habit and small leaves help survive strong wind. So, for success, choose plants which suit your soil and aspect. Choose small specimens over larger ones because they will establish better. Look at neighbouring gardens and see which plants are doing well. Plant a selection of different species. Help them by providing water and shelter until they are well established. If possible hose down with fresh water after a bad storm.

We have produced a leaflet to help you select plants for coastal gardens. It has comprehensive lists of plants based on our experience over the years and is available in paper form from the shop, or online here: https://www.duchyofcornwallnur...