Firescaping your garden.

View over Knysna from Pledge Nature Reserve just after the 2017 fire

The heading may sound a bit paranoid: however the fires of the last few weeks brought back many memories of the disastrous event of 2017. The fires of 2018 raged  from Groot Vadersbosch to Tsitsikamma, and according to maps provided by SANParks the total burn scar in the Garden Route was 104,500 hectares, 75,400 of which was in the Wilderness and Knysna areas.  Although the   fires did not directly  affect  most Knysna residents,  the smoke,  the red glow on the mountains, the incessant heat and wind  all stirred up many emotions.  After the tragic loss of life in Farleigh, the biggest long-term impact of the fires will be felt for many years to come, environmentally and financially.

Fire has become the new norm, not only in our part of the world but also globally. Due to global warming we can expect drier hotter summers and winters with less than average rainfall.  In Knysna  many  properties were destroyed last year, possibly because the vegetation around the homes  was dense and high, acting as perfect receptacles for flying embers.  Alien invasive species, some plants such as palms, bottlebrush, conifers, pines and highly combustible fynbos species all contributed to the destruction of neighbourhoods.

Living in areas  which  are  fire prone should influence home owners and garden  designers to look afresh at plant choice and garden layout.  Property  owners  should re-assess the landscape around their properties, how to create barriers in order to ward off wild fires, and how to embrace “zone” planting.    Research has shown that 90% of the time, homes are destroyed by ignited embers and not by a wall of flames:  we need to rethink the traditional “foundation planting” of trees and shrubs up against a house, designed to blend structures with nature for maximum curb appeal.

Defensible spaces -pathways

The practical aspect of fire-safe landscaping should include meadows and defensible spaces. The idea is to create an airy, open “defensible space” around your home and plant nothing that touches the structure or looms above it.  Surround your house with walkways or paths, keep them clean of dried leaves, and plant drifts of fire retardant plants. Although lawns are water guzzlers and require high maintenance, they should not be ruled out completely as they create a perfect barrier. Any garden needs trees, but they should not be planted closer than 3.5m from  structures, and preferably not in groups as they create ‘fire ladders’ that help flames spread from one plant to another. Trees with high resin or oil content such as conifers, pines, eucalyptus, bottlebrush, and citrus should really be avoided, also palms as their  fibrous bark and shaggy dead fronds ignite easily, creating fierce fires and showers of flying embers.  Vines framing your entrance and other highly combustible vegetation near your home also serve as easy fuel for wind-borne embers.

Succulent garden

Whether or not a plant will catch alight, or keep a fire going, or propel a fire is determined by its physical characteristics. Fire retardant plants are directly related to the amount of stored moisture and fuel eg. succulents (high moisture content) and therefore fire-retardant, versus pine (high resin content) which is highly combustible.

Flammable plants and fire retardant plants have certain characteristics.  Get to know their  characteristics  in order to choose the right  plants for the right place if you are going to embark or establishing this new concept of gardening.

Plant characteristics:

  • Needle and blade like leaves plants are more flammable than broadleaf plants.
  • Evergreen plants are more flammable than deciduous plants.
  • Plants that produce a low amount of litter are less flammable than those that produce a lot of litter.
  • Plants with high moisture content in their leaves or stems are less flammable than fine or thin leaves.
  • Plants with sap that looks more like milky water are less flammable than plants with thick, gummy or resinous sap.
  • Plants with fragrant and aromatic qualities are more flammable than plants without it.
  • Silver or grey-green leaved plants  have a high mineral and ash content, they are less flammable that those without. However, some plants, such as the highly ignitable indigenous fragrant salvia or blombos do not follow this rule.
  • Hairy plants are more flammable than hairless species.
Fire retarding Star jasmine

All plants may catch fire, however the ability of any of these plants to retard or resist depends on their condition. Moribund, diseased, and water stressed plants are more flammable than properly cared for plants. The essence is good housekeeping, good landscape maintenance which is essential for fire safety and not plant selection alone.

In a follow up posting I will expand on the Defensible Space – Firescaping Zones which will include a list of suggested plants.