As summer warms up, all homeowners need to think about being bushfire safe. This means getting rid of rubbish, clearing weeds and debris and cutting back overhanging branches so they are clear of buildings.
If you live close to bushland, also remove flammable wood-based mulches especially from around buildings. Replace flammable mulches with inorganic products such as gravel that don’t burn, or lush green groundcover plants including lawn. Mown green lawn is a great barrier against fire. Also mow or whippersnapper along fence lines to remove weeds and long grass.
While plants can’t stop a fire, they can help protect homes and property from ember attack and slow the passage of flames. Plants that work in this way can be trees, shrubs, perennials or groundcovers but they need to be lush with high moisture content in their leaves and be low in volatile oils. It is important to realise however that any plant can burn if conditions are right.
To increase the effectiveness of plants to act as fire retardants, keep them green and healthy with regular watering. Prune out old or dead growth and remove any build up of dead leaves. Keep weeds and dead grass away from the base of trees and shrubs and rake up fallen leaves and bark, which may be flammable.
Time and time again gardeners who’ve experienced a bushfire and seen their homes survive when others around have been destroyed, praise the work done by the tall, deciduous trees around their garden. The dense canopy provided by deciduous trees such as oak, liquidambar and elm can protect from flying embers. Even if these trees are scorched, they are unlikely to erupt into flames and most recover after fire. As well as trapping embers and sparks in their lush canopy, they can also reduce the wind speed as the fire approaches.
Other fire retardant trees include native rainforest species such as water gum (Tristaniopsis laurina), lilly pillies (Syzygium australe and others), native frangipania (Hymenosporum flavum), tuckeroo (Cupaniopsis anacardioides) or Illawarra flame tree (Brachychiton acerifolius). The ‘flame’ in this tree’s common name refers to the colour of its flowers not its reaction to fire!
Dense non-flammable shrubs can also protect from ember attack when a bushfire is raging and slow the passage of flames if the fire does arrive. Suitable candidates could include hydrangeas and native shrubs such as correa (Correa alba) (pictured). Keep shrubs clear of debris such as dead growth and fallen leaves.
Perennials and groundcovers
Low plants are particularly useful to slow a fire down and reduce spot fires, allowing time to put out the flames or for the fire to run out of energy before it can ignite the house, fences or outbuildings.
Massed agapanthus is a great fire-retardant planting choice. Although the leaves may burn during a fire, these perennials reshoot after a fire, allowing the garden to quickly recover from a burn. Other good choices are succulents such as ice plant, guinea flower (Hibbertia scandens), dichondra (Dichondra repens) and clumping grass-like lilies such as dianella and lomandra.