Creating Coastal Gardens

Coastal garden style offers creative opportunities as well as hazards for landscapers.  There is much greater exposure to the elements, and location is important since gardens on the west tend to get much more rain than in the drier east.  Creating the right type of coastal garden for your location is increasingly vital given the greater extremes of wet and dry weather being experienced due to climate change.

There is a constant risk of erosion from the sea or wind while flooding can occur in winter or during storms.  Sudden heavy storms especially on western coasts can cause flooding both from the sea and water courses taking water from inland to the coast. Salty sea spray can affect the fertility of the soil along all parts of the coast.  Temperatures tend to be higher allowing earlier flowering times and lush greenery.

Interest in this garden style is increasing, especially among inland gardeners inspired by seaside visits to incorporate elements as an answer to droughts and high winds.

Using local materials for the hard landscaping will enable the garden to fit more closely into its natural environment since colours will come from the same soil shade palette.

Drainage

When creating a coastal style garden within either a new build or existing garden, watering requirements are a priority. New sustainable drainage flood water regulations are set to come into force this year, which will affect the landscaping of all developments, residential and commercial.

Installing underground rainwater harvesting tanks linked to household drainpipes provides valuable water supplies for use during dry periods.  Being kept underground prevents evaporation, and keeps the water constantly cool.  Such tanks can be placed under paths and drives during the garden construction process. By using gravel, permeable membranes and permeable paving, any surface water can also be directed into the tanks thus mitigating the impact of storm water surges. Automatic watering and porous pipe systems can be linked into the rainwater harvesting facilities.

Cultivating sandy soils

Gardens on new build developments or adjacent to house extensions frequently result in large quantities of builders sand within the soil.  Removing it is rarely practical.  Depending on quantities some can be moved to help provide foundations for paths or patios.

Altering the nature of sandy soils can be hard work.  Digging in organic matter such as farmyard manure or composted bark will aid moisture retention but it is essential to dig in large quantities – at least 30 centimetres (12 inches) in depth. This will also make the soil more alkaline.

Working with a sandy soil can be advantageous to landscape gardeners. Sandy soils warm up quickly in spring and it is harder for weeds to become established. Any weeds that do grow tend to be less vigorous, making weeding much easier. Sandy soils are naturally free draining, naturally acidic, low in nutrients and dry out quickly. Adding some compost in planting holes will benefit new plants.  Once established, plants will be more sturdy, slower growing, resilient to changing conditions and much more drought tolerant.

Design creativity

Stylistically, coastal inspired gardens offer considerable scope for creativity in terms of design and planting. Rocks, shingle and gravel can define boundaries as well as acting as a mulch conserving soil moisture for nearby plants.  Decking and seating areas involving reclaimed silvery wood & metal feature strongly in designs of this type. Branches and driftwood can act as centres of interest, providing a sustainable element since these materials break down slowly to improve the soil and creating homes for insects.  Adding in deckchairs rather than tables and chairs immediately evokes the coast.

Such gardens frequently appear in the RHS Chelsea Flower Show and this year is no exception.  The mgr Changing Tides Garden designed by Lucy Mitchell incorporates clusters of Kent ragstone boulders used as planters for naturally tough coastal plants such as sedums found along the shoreline of shingle beaches. Reclaimed timber is used to evoke the ambiance of seaside groynes, while providing some shelter and protection to larger plants like Pinus Sylvestris and Juniper squamata.  Extra nautical elements can be created from old boat hulls or using old fishing nets to provide support for vertical planting.

Planting options

Planting options are extensive, although there can be differences between east and west.  The mild winters experienced along the coasts of Devon and Cornwall have allowed many subtropical plants to thrive as at Trebah where rhododendrons, magnolias, camellias and gunnera thrive. Over on the more windswept and sand dune coasts of East Anglia, coastal gardens tend to be less lush and feature many more small leafed plants like tamarisk, gorse, heather and achillea.

Festuca, Marram and other ornamental grasses play an important role in all types of coastal or sandy gardens as they help to naturally stabilise the soil. Grey leaved and narrow leaved plants like sea buckthorn, wild roses, buddleia, hebes, heliochrysum, stachys byzantine, mullein, fuschia, sea campion, sea holly, sea kale, thrift, cotoneaster, sedum, lavender, dianthus, rosemary and sage do well in these drier soils frequently self seeding from year to year.  Plants with glossy or leathery leaves like holly are able to keep moisture in their leaves for much longer, although they may need staking initially until a strong root structure is established. 

Adding in some taller shrubs and trees will provide windbreaks and offer shelter from strong winds. Slated fences are better than solid ones as they will withstand the wind better. Slowing the wind is better than trying to block it completely as the resulting air turbulence can create additional problems.

Angela Youngman

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