Monday, 24 December 2012

Small is beautiful - when it comes to shrubs

Plants grow!  This may not come as a complete surprise, but many of us, myself included often think that the shrub or tree that we plant will take ages to reach a satisfactory size.

These Ceanothus, Californian Lilac were
less than a metre high a year before and
have taken off.  Not a good position next
to a shed with timber walls.
Not so!  If given a modicum of care, regular watering - not necessarily a huge amount but done at around twice a week and preferably via a drip system, plants will grow noticeably bigger.  Drippers deliver water at ground level, not into the air where much evaporates, so most of the water delivered by drippers will percolate down to the roots.

In addition to aid the growth this year, we have had the season on our side with not so much rain over winter, but good late rains in September, which with the added warmth and daylight hours of the equinox period, meant that plants really took off.  Modest little shrubs became two metre high shrubs and began to reach rooflines and come close to tree canopies.  Somehow the process of raining is more effective than drippers, probably because whole areas of the garden are watered and not just the spots where the drippers reach.

The Ceanothus shrubs as shown above and right are growing next to a shed with wooden sides.  The Ceanothus is a short-lived Californian native that grows fast, and dies within 15 - 20 years by which time it has many twiggy, dead branches and will burn easily.  It is designed to burn as a way of renewing and allowing young seedlings space and nutrients to grow.

If grown near trees it can create a ladder effect whereby a grass fire or flying embers from a bushfire can set the Ceanothus on fire and in turn the flames can reach up into nearby trees where the fire can really take off.

These shrubs could be pruned low, although they don't respond to pruning very well, or taken out altogether.  Watch this spot, these shrubs will be removed!

Monday, 6 August 2012

Shrubs: the Good, the Bad, the Ugly

The flowering apricot is more of a small tree, but it 
perfectly exemplifies the attractive bare branches of winter,
though here it shows its typical early blossom 
amongst the bare stems.  GOOD

With winter well and truly here, the nature of the deciduous shrub becomes obvious - it loses its leaves and reveals the scaffolding of its branches.  For many species the winter pattern of its branches is a beautiful sight, for although it offers no solid screening as it does in summer, it nonetheless creates a gentle softening of a vista with the tracery of those bare branches.

The Hydrangea has very few dead leaves
caught in its branches.  Its leaves break
down quickly once they have fallen.

Deciduous shrubs do more than reveal their branches, they also show that they have very little build up of flammable material.  The freshly growing leaves are, more often than not, low in volatile oils, contain a high proportion of moisture and come from climates which have cold winters and mild summers.  They are not designed to burn unlike shrubs adapted to water saving such as those from a mediterranean climate.  The dead leaves of the deciduous shrub tend to fall to the ground and, in most cases, will quickly decay over the winter becoming composted and eventually part of the soil.  Thus by summer they pose no hidden fire threat either from the new moist leaves or the old ones becoming part of the top soil.

By contrast an evergreen shrub may build up much dead litter caught in the branches, that cannot readily be seen, because of masking by the evergreen leaves.

A Book Leaf Cypress looks green on the outside, but part
the leaves and there is dry and inflammable litter inside.

Euonymous japonica

Of course, there is great variation and a spindle berry, Euonymous japonica, is quite low in flammability, although an evergreen.  Its leaves are quite large, fleshy and moist without volatile oils.  When looking into the shrub there is very little in the way of leaf litter caught in the branches.

To sum up, choosing deciduous shrubs are often a safer choice for fire-prone areas, partly because they come from cool temperate areas and are not inherently inflammable, but also because it is easy to see if there is a build up of inflammable material.

If you do choose evergreen shrubs, choose ones like the Euonymous with broad, fleshy leaves.

If you really like plants such as diosma or artemisia keep them small and low to the ground - less than a metre - this regular cutting back will reduce the litter build up.
Artemisia, Wormwood, is best cut back regularly, but it does
have volatile oils and needs controlling.
A qualified GOOD.  High maintenance!

Saturday, 7 April 2012

Season is changing at last

We can now begin to relax as the threat of wildfire diminishes with the cooler temperatures and the few showers that we have had over the past few days.  Here in Balingup, South West, Australia we have even had a couple of mild frosts in the more open parts of the property.

Nonetheless, because it is more pleasant working in the garden and around the house, it is a good time to continue to make the property more firewise and defensible in the case of a bushfire.

A garden in Bridgetown, in South West, WA,  is landscaped to minimise
the risk of bushfire.  Note the stretch of green, moist lawn, the wide gravel
path and the selection of plants that are low in flammability.  
These include: roses, agapanthus and several varieties of deciduous trees, 
such as a liquidamber on the left and a Chinese Tallow tree, centre.
An excellent web site has been created in Napa Valley, Southern California, which has a similar mediterranean climate to ours, i.e., long, hot, dry summers with cool, moist winters.

The website is part of the Firewise Communities network which spans many parts of the fire-prone areas of the US.

Here is a link - Napa_Firewise - to a whole section on Defensible Space - that important area immediately around the home which we sometimes call the Building Protection Zone, BPZ, or the Circle of Safety.

It usually measures 20 m or more from the external walls of a house depending on terrain and whether near tall forest areas which can be highly fire-prone or to more open country which may present less of a risk. This defensible space is aimed to provide an area for easy access to the dwelling for fire fighters and to have little or no material in this space that is likely to catch fire or dry out and become inflammable.

The choice of plants near a dwelling can have an impact on to how vulnerable a property is to a bushfire.  For example, green, moisture laden grass in the form of a lawn is unlikely to support a fire, whereas a hedge of 2 metre-high evergreen shrubs containing dead leaves and twigs may help fuel a fire, especially if the leaves contain volatile oils.  A hedge of rosemary or of melaleucas near a house is to be avoided.

For more information about this the Australian Victorian Country Fire Authority has created an online Plant Selection Key which I have found extremely useful and illuminating.

It will help you redesign your garden to be more firewire.

Friday, 23 March 2012

They have to go. The gum trees that is!

Some years back I had a lovely old property in Bridgetown that had a jarrah-weatherboard house, beautiful old camellias and a magnificent Lemon-scented Gum, Coyrymbia citriodora.
The tree had many seedlings and was a favourite feeding tree for the red-tailed Black Cockatoo.
This old Lemon-scented Gum was
twisted into unusual shapes and was
a fine tree, though it did drop bark in
summer and plenty of inflammable leaves

I planted three seedlings of this tree at my present property in Balingup and they have grown very well in three to four years.

Now I realise they will only grow much bigger and have the potential with their bark and leaf fall in summer to add to the fuel hazard around the garden.  I don't have the time to spend raking and mowing the leaves to stop them building up, so we had to make a decision as to whether to have a continuing maintenance problem or take them out whilst we still can.

To have a professional tree feller come and remove the trees when they have grown more can cost thousands of dollars, so the decision is to take them out.

With new rules being applied in some Shires about a 20 m Circle of Safety or the Building Protection Zone that should apply around houses and sheds, it makes sense to act earlier rather than later and reduce the fire hazard on our properties by removing these trees.
(1) The lemon-scented gum has branches
removed first and then the bare trunk will
be cut down with a chain saw.

The essential feature of these zones is to remove inflammable material from these areas from the ground and to keep trees that are near the house or sheds at least 10 m apart.  The 10 m being from the outside of the canopy to the next.  Trees with volatile oils in their leaves need to be carefully placed, trimmed back or removed altogether for improved safety.  Trees if kept are to be pruned up at least to 2 m.

(2) The Gum tree has had the last of the
branches removed ready for the chain saw.
The tree on the left is an English Elm which
is deciduous and on the right is a poplar
which tends to dampen down fires though
they will get scorched.

There is still debate about the role of deciduous trees which may provide a screening effect and if kept moist and without dead material held in their branches can take the heat out of a fire.

Tuesday, 20 March 2012

Autumn is really coming?

Perhaps the season is really changing and the cooler weather is beginning.  Already the days are noticeably shorter.  Well, so they should be as the equinox is just about upon us.

Any rain will be gratefully received, not only to freshen up the gardens and the forests, but also to reduce the risk of wildfire.  Last week, near Balingup, we experienced a bushfire emanating from a nearby plantation, that took three days to control.  Friends, not far from the fire, decided to move out whilst the heat was on.

Eucalypts on the front verge can be a mixed blessing.  In this case this is
litter from remnant forest trees, Eucalyptus patens, Blackbutt, which over
summer routinely drop masses of leaves, twigs and bark that build up
against the front fence.  The mix contains volatile oils, is very dry and is
designed to burn.  Regular mowing and/or raking to remove the litter
is needed to reduce the fuel load.
The good aspect about the friendlier weather is that it is considerably more comfortable to be out in the garden.  There's plenty to do from a risk management point of view when it comes to reducing fire risks.  Even this morning I found a patch of dry grass in one section of the garden which I had overlooked all summer - just the place for an ember to fall and catch the grass and some well-placed dry eucalyptus leaves.

Time to make use of the gardener's friends: rakes and secateurs to tidy up and reduce the build up of fuel.

The garden will look more presentable, too!

Monday, 19 March 2012

Firewise Landscapes
In the South West of Australia we have a mediterranean climate, i.e. hot, dry summers that seem to last for at least five months and cool, wet winters.  The winters have, in the past few years, been notable for their lower than average rainfall.

The Red-flowering Gum, Corymbia ficifolia,
comes from the south coast of Western
Australia and is quite at home in California
or other places with a similar climate.
It has volatile oils in its leaves, drops copious
leaves and small twigs over summer and is
thus highly inflammable.  It needs to be
planted well away from the home and well
maintained so that dry litter does not built
up to become ground fuels for a bushfire.
We share this climate with just a few places in the world, namely southern California, the Cape Province of South Africa, parts of Chile and the countries surrounding the Mediterranean Sea.  The plants that are native to these regions will in many instances grow happily in any other mediterranean-climate country.  The trees and shrubs of these countries have adapted to surviving the long summers by a variety of methods, including making use of fire to regenerate trees and shrubs and to spread seed.

In our garden design and in choosing plants we need to be mindful of whether we are at risk of destructive wildfire, both with respect to what sort of plants are in our gardens, where they are located and our proximity to forests and scrublands.

There are many factors which will influence whether we are well prepared to survive a bushfire.

In this blog we will discuss and try to inform the debate about how to make our properties and the surrounding landscape more firewise and less dangerous.