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Gardens that thrive in the heat

By Ben Sims
24 January, 2019

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The main factors of a thriving summer garden are plant selection, planting time, plant location, soil preparation, irrigation, mulch and specific summer maintenance or what I call TLC.

Plant selection:

So, if we start with the garden beds then I recommend WA native plants or Eastern states plants with a good track record of performing well in Perth. The beauty of native plants is that they are not reliant on any soil preparation if you choose the correct plants. There are thousands of suitable native WA plants that are available cheaply in tube stock form. The tricky bit is plant selection if you don’t have experience. Plants from the Myrtaceae(Eucalypt family) and Proteacea(Banksia family) are generally a good start as these are generally sand lovers and very water wise once established. They also generally respond very well to pruning.  You can experiment with other plants from other families but if the ‘bones’ of your garden design has these plants it’s hard to go wrong. There are heaps of very attractive and stylish plants from these families and I will name just a few in this article. Myrtaceae include genera such as Thryptomene(allot of small shrubs and ground covers), Melaleucas(trees through to ground covers), Regelia(small to medium shrubs), Corymbia(Red flowering gum which can be a grafted small feature tree),  Kunzea(medium to large shrubs), Eremaeae(small to medium shrubs), Hypocallyma(small shrubs), Verticordia(small very waterwise shrubs), Peppermints(trees through to shrubs), Callistemon(small shrub to large shrubs/trees). Some well-known edible but not necessarily as waterwise examples are Guava, Lily pily(some are very water wise), midyium berry, clove etc. Some Proteaceae examples include Adenonanthos(Albany Woolly bush)(screening prune to size), Hakeas(Pin cushion Hakea is beautiful and can be pruned to a small shrub/tree), Banksia blechnifolia(very attractive tough ground cover). The above suggestions are just a start to show that there are very attractive water-wise options that can fit a lot of garden styles.

Planting time:

Planting tube stock in the middle of summer is a recipe for disaster unless you give them a lot of water. It is far better to plant when the weather cools down. An ideal time is early May when the temperature decreases, and rainfall starts to increase. Alternatively, if you are installing turf, tropical plants, exotics or edibles then the warmer months are better provided with the soil preparation and reticulation/watering are up to a decent standard.

Plant location:

It is very important that the location of your plant is as similar to its natural location as possible. Allot of native plants love full sun however there are many that are from down south that grow under canopies or in cooler climates that would prefer some shade. Allot of tropical plants do well indoors or in deep shade because in nature they grow under many layers of canopy. Most warm-season turf grasses require at least 6-8hrs of full sun all year however varieties such as Buffalo and Sir Grange Zoysia can take more shade. Plants such as Azaleas like to be protected from hot afternoon sun in Perth.

Soil preparation:

For non natives this is essential. Why would you pay $10-$15 per meter for turf and not spend $10-30 per meter for soil underlay which will give the best long-term water and nutrient savings and lower management? Why would you buy a plant for $10-$20 and not give it $5-$20 of soil preparation? In the long term skipping on good soil preparation just doesn’t add up. For turf, I recommend at least 10kg of Soil Solver(Kaolin clay) and 20kg of matured compost per square meter and for exotic plant installs a good balance of Soil solver clay, manure and soil improver mixing in 50/50 with the existing sand to form a quality soil. I don’t recommend soil yard mixes as you are buying a lot of sand which is in abundance in most Perth backyards and the additives might not be very good quality, to begin with, and break down in as little as 1-2 years leaving you with the sand you began with. Clay is permanent and the right type of clay is critical. Bentonite clay which is typically used is too reactive and can block soil drainage pores if overused and if underused won’t get the required 5-10% clay content which helps reduced water repellency and nutrient retention.

Irrigation:

Cheap irrigation isn’t good irrigation and you can’t go past a professionally designed system that uses professional quality components. Allot of what people think is a decent product is inferior quality and not pressure compensated meaning different sprinklers on the same zone won’t use even amounts of water. Also, a lot of what you find you can’t replace the nozzle as they are inbuilt and a throwaway design. Professional sprinklers come with a flushing nozzle and you can add your nozzles or replace a broken or blocked nozzle. For lawns on mains systems you can’t currently beat MP rotator nozzles and for bores, Rainbird RVAN nozzles are great because they can be flushed manually of debris whilst the nozzle is operating, and you don’t need to take the nozzle off and add a flushing nozzle. There is a new RVAN rotary nozzle that I will be learning about today at the 2019 launch. Rainbird RVAN advanced rotary aim to beat the MP rotator which could be great news and moving the industry forward.

I find a lot of poorly designed systems with too many sprinklers per station, sprinklers too far apart or in strange locations, cheap nozzles/sprinklers used. Having the lawn and garden on the same zones is a bad idea as you need to hydro-zone your retic system meaning grouping plants of similar water use and setting up each zone accordingly.  

A lot of systems that work poorly haven’t even had a plumber or retic guy do a static pressure test from the cut in to show the actual operating flow under 250kpa which is the internal pressure the retic system operates under.

Mulch:

The best types of mulch are large particle mulch(pine bark or woodchip) as it allows water in easily and prevents evaporation from the soil surface. What you don’t want is fine particle ‘fluffy’ mulch as it’s more difficult for water to reach and penetrate the soil and some even compete and ‘wick’ the water from the soil surface. The depth of mulch is also important and you want at least 35mm (natives) to 50mm(most plants) in depth depending on what you are planting. If there were weeds or grass there before you might go as deep as 100mm for suppression.

Spring/Summer TLC

Something I have recently learned about and now use is organic liquid products through a Hortex sprayer. This is fantastic for lawns and large areas as it’s cheap and easy to apply or you can add them to a watering can. The products I use are Ecowet(Commercial wetting agent), Ecovital(seaweed plus fish emulsion), and Powerfeed commercial(strong complete liquid fertiliser). The Ecowet is an organic polymer that can break the waxy coating on the surface of the soil and allows far greater soil wetting and deeper watering. Ecovital is great because it has all the benefits of Seasol and can be used regularly like Seasol but it is also a light fertiliser and contains humates and other natural additives which aid in plant reducing stress. Because it has a low phosphorus content and lower fertiliser content it can safely be used on natives or a foliar spray in most weather conditions on turf or fruit trees without the risk of burning the leaf. This aids in faster uptake and repair as it doesn’t need to travel through the soil matrix to make it into the plant. The plant can take up the nutrients through the leaves and stems. Be careful to not try this with strong fertilisers or even Ecovital on a really hot day 30C or more. All wetting agents must be washed off the leaf and into the soil as they break up wax and can break the waxy cuticle in the plant leaf.

If you wish to learn more about establishing or revitalising your native garden, then please feel free to give me a call.