Preparing for a Hot Tropical Summer

I know that Summertime in some parts of the world is a wonderful time for gardeners.  Here in my corner of Oz ... it can be a woeful time!  Located only a mere 2300 kilometres (1450 miles) from the Equator and averaging around 320 days of bright glorious sunshine every year, my garden is positioned in a hot dry spot on the planet.

Summertime can be excruciatingly hard on both the garden and the gardener.

Summer months are always hard-going with daytime temperatures that average around 31°C.  Of course the mercury can climb to 40 (104F) some days.  Unfortunately the heat is not a dry heat, it's sticky and uncomfortable as the humidity is frequently between 60% and 75%.  We don't fare any better at nigh time either as the night temperatures average around 25°C (77F) and there is little relief from the high levels of humidity, even then.

It's the humidity that makes life hard for this  gardener during a north Queensland summer.  I rarely venture out into the garden during this time of year, so the garden has to survive without the usual care and attention that I lavish it with during the Autumn to Spring.

Preparing for a torrid summer is often a useless, forlorn exercise ... especially if we get cyclones with their destructive winds and the torrential driving rain of a 'wet' season ... but it has to be done, and it begins long before summer arrives.

First, choosing plants that can withstand fierce sunshine, sweltering temperatures and driving rain is a great starting point.  Plants such as the old-fashioned Rosa-sinensis is a staple in every garden I've had here in the northern tropics of Oz.  They are among  the most resilient, hardiest plants I've every grown ...

... and I can't recommend them highly enough.  My favourites are the hybrids 'Roseflake' and 'Snowflake'.

I also couldn't do without Palms ... again, they are just such a wonderful survivor in our climate and conditions.  Top of the list is the Dypsis lutescens - the clumping Golden Cane Palm.

I could go on and on about choosing the right plants ... but that's what I cover in most of the other posts on this blog.

So let's get on with the preparations needed to survive a Summer.  Next, there's the trimming back ... this begins in early Spring so there will be lovely new young growth that will hopefully bounce back from the torrential rainfall we can receive.  I spend at least a whole weekend cutting back the bed of Acalyphas out the front of the house ... (another plant I would highly recommend) ...

... and the bed of Hibiscus rosa-sinensis, Pseudomussaenda, Russelia, Combretum and Mussaenda on the other side of the front stairs.

These beds are then given a good feed of blood and bone fertilizer that's watered in very well.  Then, after the Spring months are over, the plants are ready for the onslaught of summer.  Here's a view of them right now with all their wonderful healthy, strong, new growth.

Another vital ingredient for a well-prepared tropical garden is mulching.  This again is done before summertime so there's more chance of the mulch actually providing cover long before the extreme heat and strength of the summer sun sucks every ounce of moisture from the ground.

In the front garden beds pictured above, I use scoria ... a type of volcanic rock ... as a mulching agent.   I also use scoria on my Pentas bed.  This photo gives you a closer look at it.

Why use a non-organic mulch?  The most important reason for this is that it provides protection from termites.  Here in the northern tropics, termites are a huge problem and having organic mulches close to wooden houses is just a disaster waiting to happen!  (Speaking from previous experience!)  As these front yard garden beds are all built up close to the timber structure of our house, we don't want termites setting up home in the mulch and then moving into our house!!

Termite protection aside ... scoria has other great features as well.  Being so porous it absorbs and holds a lot of water which is then slowly released to the surrounding plants over a longer period of time.  That way every drop of precious water is used in the most productive and useful way.  It's terrific for drought proofing gardens.  It's also acts like insulation protecting the soil in these areas of our property that are open to the drying effect of the intense sunlight and the winds we experience during our summer.

In other areas of the property, I use organic mulches.  In the long driveway garden beds there's always layers of leaves that have fallen from the many tall Eucalyptus trees on either side ... and it's just a matter of using the leaf blower to pile them up under all the shrubs ... as you can see clearly in the photo below.

In the newly established beds outside my greenhouse/shadehouse garden, I scatter dried sugar cane mulch all around the plants.  It's easily obtained here in my part of the world as we're so close to cane farms, thus it's a sustainable and renewable resource.

Here's a closer look at the sugar cane mulch ...

... the best feature of this mulching agent is that it doesn't become as compact and impenetrable as other organic mulches have a habit of doing here in the tropics.  It stays rather coarse and allows not only the rain to penetrate, but also fertiliser.  I've tried other types, but would never go back to them now.

One more great feature of this mulch, is that it's perfectly suited to areas that have a lot of run-off during the heavy summer rains.  This area of my property certainly has that ... as you can see from the bare patches in the lawn in the photo below, the run off from the torrential 'wet' season rainfall can be quite damaging.

I find that the dried cane sugar mulch used in those raised garden beds really knits together well and doesn't get washed away as easily as other mulches.

Pictured above is another of the areas that suffers from heavy summer rain run-off, and it's the roots of the huge Nephrolepis biserrata - the Giant Sword Fern - that mat together and hold the soil in place as the rainwater surges down the slope.  This fern, given lots of room, makes a beautiful low maintenance protective cover for areas that can be drastically eroded away by gushing rainfall.

Finally, one of the hardest parts of my garden to look after during our Summer is definitely the potted plants.
I have well over 100 pots, containers and hanging baskets in both my courtyard garden and my greenhouse/shadehouse garden.  Potted plants can be very demanding during hot summer weather.

Now while terracotta pots do indeed look fabulous, anything planted up in a terracotta pot will lose water very quickly here through evaporation.   Most of my potted plants are in plastic pots simply because they lose water less quickly.  I also make sure that the tops of all pots are mulched.  I use mostly bark chips as you can see in this potted Alocasia.

I also ensure every pot has water-retaining vermiculite added to the potting mix to help prevent water evaporating from the soil. 

Standing pots in groups in a semi-shaded, sheltered place also reduces evaporation.  This really helps many of my potted plants to get through our summer.

Hanging baskets need more water than pots on the ground.  Most of my hanging baskets and containers are in my greenhouse/shadehouse garden which is protected by shadecloth that blocks out 70% of the harsh sunlight ....

.... and is watered by a timed watering system. You can see the black irrigation pipes snaking along the top of the supporting poles.

Of course, with both hanging planters and pots it's never a good idea to water in the intense heat of the day ... the water will simply evaporate before your very eyes.  I always water very early in the morning before the sun has risen too high or I wait until the sun goes down ... and instead of a quickie every day, I give each plant a nice, deep drink every second day.  Far more beneficial!