Finding trees for coastal conditions requires more forethought and planning due to anticipated exposure to salt, sand and wind. According to Speciality Trees, solutions are available but success will depend on planting proximity to the coastline.
From left to right: Allocasuarina verticillata and Banksia integrifolia
Coastal trees are trees that are tolerant of the typically sandy and salty conditions associated with living along the coast. Speciality Trees know that some trees can tolerate direct frontline conditions, while others perform better if planted a level back and with a lesser degree of direct exposure.
Appreciating how close the landscape is to the coastline is important for tree selection. For planting right on the beach, deemed ‘Frontline coastal’, trees and plants need to have an in-built propensity to tolerate salt-laden winds. This vegetation often has fine foliage, and trees are dense in form to control erosion and provide an effective wind barrier.
Think of the low laying scrub and tea tree that can be seen at the beach! The vegetation that exists there hugs the ground as much as possible so that the harsh coastal, salty winds can scoot over the top. Within these microclimates, you will find tough growing conditions too where salt residue combines with sandy soil making establishment very difficult, but trees and plants will grow there.
In high winds, trees with narrow foliage such as Allocasuarina verticillata is considered an appropriate selection as its thin leaves offer less friction and resistance to harsh wind. This is a good coping mechanism in a frontline coastal position. In another example, the broader leafed Banksia integrifolia and the narrower growing Banksia integrifolia ‘Sentinel’ also cope well due to a waxy coating on its foliage. It is this hard, rubbery attribute that allows the trees to withstand the absorption of salt. Also consider succulents such as Kalanchoe that have fine hairs on their leaves that act to slow the velocity of the wind, thereby minimising water loss.
Banksia integrifolia ‘Sentinel’ PBR – a narrower growing, fastigiate form of Coastal Banksia
When it comes to coastal it is best to talk to horticulturists who can draw on their experience and training to know what works best. From a tree perspective Allocasuarina verticillata, Banksia integrifolia and Leptospermum laevigatum are true frontline warriors and sit at the top of the Speciality Trees list.
However, walk back 500m or a couple of streets and there exists a broader list of trees for planting in coastal suburbs. These include: Laurus nobilis (Bay Tree), Acacia melanoxylon, Agonis, Corymbia ficifolia - but not the grafted form, Olives, Ulmus parvifolia (Chinese Elm), Fraxinus griffithii, Callistemon, Prunus lusitanica (Portuguese Laurel), Juniperus chinensis ‘Spartan’ and Cupressus sempervirens ‘Glauca’ (Italian Pencil Pine). Another, Elaeocarpus reticulatus will tolerate sandy coastal soils but not salt-laden winds.
All of these have the potential of being burnt by salty winds, so it is a good idea to plant them out with other vegetation for combined protection. Make sure to improve the soil where possible with the addition of quality organic compost, additional imported screened soil and wetting agent. Don’t forget to mulch to a depth of 80mm. There is a lot of aquaphobic or water-repellent coastal soils around Melbourne so soil improvement is a must to ensure tree establishment in this challenging environment.
For a broader list of coastal trees CLICK HERE.
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