Next time you’re at the beach where there’s natural bushland, take a moment to scan the sand dunes and look at the trees and shrubs that lie behind them. These are true seaside plants. They’ve evolved to withstand salt air and battering wind.
Although there are many different plants, they have some things in common including tough leaves - leathery, shiny or spiky – and low growth. Often seaside trees are gnarled and shrublike near the coast but taller and more graceful in more sheltered inland areas. The dunes will have vines and trailers creeping across the sand and clumps of tough grassy plants.
It’s also worth walking the streets near the beach in a coastal suburb to spot the ornamental plants that do well in this harsh environment. Look for plants that are growing well and flowering but avoid any that are yellowed, tattered or damaged by the seaside conditions.
Often plants are sheltered by a wall or hedge, which gives a clue to how to plant in a seaside region. Establish toughest seaside plants as a windbreak to protect ornamental but still salt-tolerant choices. Plants that can’t take the wind or salty conditions need to be grown in well-sheltered spots such as behind the house.
Native seaside plants such as coast rosemary (Westringia rosmarinus), coastal tea tree (Leptospermum laevigatum) and coast banksia (Banksia integrifolia) are good frontline choices. There are also plants from seaside locations around the world. New Zealand has excellent seaside survivors including the New Zealand Christmas bush (Metrosideros spp.), coprosma (Coprosma repens) and various hebes (Hebe spp.), which all lend themselves to hedging, and New Zealand flax (Phormium tenax), which forms large bold clumps of strappy leaves.
From the Mediterranean region come oleanders (Nerium oleander), rosemary (Rosmarinus officinalis) and shore juniper (Juniperus conferta), which all make tough seaside plantings and offer shelter to traditional seaside plants such as hibiscus.
The beautiful frangipani is also an asset beside the sea. Its tough branches and leathery leaves withstand the winds while it provides fragrant flowers through summer. Other plants can be grown beneath its sheltering branches.
Ground cover choices
Living ground cover and clump-forming plants can be used to cover and stablise the often-sandy soils found in seaside areas. Good choices include golden guinea flower (Hibbertia scandens), dianella and lomandra, which are all native choices, along with the cushion bush (Leucophyta brownii), one of the best of all native coastal plants.
For year-round colour as well as soil protection include the sprawling silverbush (Convolvulus cneorum), which has round white or pinky mauve flowers and silver leaves and is native to the Mediterranean. As well as tolerating seaside winds, this plant copes with dry soils and hot sun. Also from the Mediterranean is pride of Madeira (Echium candicans), which has spires of purple-blue flowers in spring and summer that are much loved by bees.
Another useful seaside plant to mass plant is dietes. This iris-relative is as tough as they come. There are species with white and purple flowers and others with yellow and brown blooms. These plants are often used in curbside and roundabout plantings near the coast - a sure sign that the plant is a survivor.
Treat seaside plants like any garden plants with regular water, fertiliser in spring and clipping to maintain size and shape. Plants that are sheltered by a wall or frontline hedge planting may need to be kept pruned below the height of the barrier to avoid salt and wind damage.
After particularly strong winds that are heavy with salt, any plants that are prone to salt damage should be hosed to clean off any salt that’s clinging to their leaves.