The magic of mulch

Sunny, hot weather usually cues us that we need to get out and top up the mulch in our garden beds. But there are other reasons why your should mulch (or top up your exisiting mulch layer) at the start of summer. Here’s a few other benefits that mulching will bring:

• Regulate soil temperatures - Mulch helps to regulate soil temperatures and supports plants that are coping with extreme weather. A mulch layer reduces heat absorption and will be cooler than soil directly exposed to sun.

• Prevent moisture loss. Moisture loss occurs when the sun causes evaporation. But windy weather can also dry out the soil and stress your plants.  

• Help prevent spread of disease. Mulch provides a physical barrier that protects against soil borne diseases. For example, mulching under roses can help stop black spot fungal spores in the soil from being splashed onto the leaves during a rain event.

• Suppression of weeds. A mulch layer will block light and therefore prevent many seeds from germinating.

• Improves soil. Some mulches such as pea straw are high in nitrogen and as it breaks down this nitrogen returns to the soil increasing nutrient content available to plants.

• Protects from soil erosion. Without a layer of mulch covering the soil, top soil can run off your garden beds during heavy rain events.

• Increased production. Studies have shown that plants grown in mulched beds grow faster, contain more chlorophyll, and greater root growth. If you are growing fruit and vegetables, you will harvest more food from a crop that has been mulched.

• Indirectly, mulch can help reduce insect activity. By helping plants to improve their overall health, they become less susceptible to insect attack.

Types of mulch

There are many different materials you can use for mulch and you will find something suitable for every garden. 

• Straw mulches (Pea Straw, Lucerne Hay, Sugar Cane) - great for the veggie patch, they can be bought in compacted bales. The hollow centres of the straw also has an insulating effect. Pea straw contains nitrogen that will break down into your soil, improving the overall condition.

• Bark mulch - inexpensive and lightweight, bark mulches are easily spread over the garden. Larger chunks of bark will take longer to break down, but may blow away in windy weather. Bark mulch is not the best choice if using it in the vegetable garden, as it can pull nitrogen away from the plants.

• Stones/rocks/gravel - gravel mulches are great for their water holding capacity, and also providing warmth to soil. In winter this can help support plants that don’t like cold.

• Lawn cuttings. You can use dried grass clippings on your ornamental garden or veggie patch. This will break down and provide a good source of nitrogen. Just don’t use cuttings that have invasive weeds or if you have sprayed your lawn with herbicides.

• Leaf litter from deciduous trees - if you have a deciduous tree, you have free mulch! In autumn, throw your leaves onto the soil and it will break down into a beautiful soil conditioner. Why waste such an amazing natural resource!

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Gravel mulch

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bark mulch

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straw mulch

Some tips for mulching your garden

• A good guide to how much mulch is to apply around 5-10 cm layer of mulch

• Make sure the soil is damp when the mulch is applied, and then water the mulch once you have laid it out

•  Avoid letting the mulch touch the stems of plants, as it can cause the plant to rot

• If the mulch becomes water repellent, soil wetting agents can be applied to rehydrate it

• When mulching trees, make sure you go right out to the canopy line to make sure you are protecting any shallow roots
  

Helping your garden survive summer

You may have noticed the government running ads promoting the Target 155L water saving campaign. While we are not officially in water restriction stages, it's an indication that may be where things are heading, and if it does the first thing to suffer is our gardens. 

Some gardens fare better than others in the heat, and this all comes down to plant choice, along with some  key gardening practices. 

Choose plants that have lower water requirements

• In general, Australian natives are a good choice as they are used to much less rainfall than exotic plants. Lilly pilly, kangaroo paws, crowea, correa, coastal rosemary, native grasses, eremophila and native daisies not only fit in beautifully with other species, they provide a valuable food sources for native birds and beneficial insects.

• Plants with grey tones.  It is safe to say that if a plant is grey and furry it's fairly certain it has evolved to live in dry conditions. Plants like lavenders, euphorbias, convolvulus, helichrysum and lambs ears have grey leaves that reflect light away from them, helping them withstand the hot summer sun a lot better than others.

• Plants with leathery leaves are another indication of toughness! Magnolia Little Gem, Bay Laurel, Rhapiolepis indica are just a few examples. Just take a drive along the coast and you’ll see them growing happily.

• Plants that thrive in Mediterranean climates also grow well here in Melbourne, so if you have just been to Greece and feel inspired then you are in luck! Think of the herbs used in Mediterranean cooking - rosemary, sage, oregano, thyme.  Not to mention olives!  All of these thrive in hot weather and don't need much water. 

• Succulents seem to be finding their niche as our climate changes. They thrive in coastal gardens and are happy with very low watering so these plants will continue to grow in popularity as more of us discover their true value in the garden.

Supporting your plants through summer

There are a number of things you can do to give your plants a better chance of making it through summer.

• If you only do one thing, then let it be mulch!  A good layer of mulch helps insulate the plant roots from the worst extremes of the weather, and also helps the soil retain water so it doesn't dry out as fast.

• Watering in the morning or evening directly on the soil rather than the foliage is a more efficient use of water as it's going straight to where the plant needs it. There's also less risk of evaporation. If you have a drip irrigation system, do periodic checks to make sure the nozzles are not blocked.

• There is evidence that using Seasol on your plants can increase their resilience to summer heat, and helps keep your plants healthier, so a regular application can be a big boost for your garden.

• If you have plants with burnt foliage, don't be tempted to cut it back right now.  This will only encourage the plant to put on tender new leaves which will be exposed to the hottest summer sun and will likely burn them as well.  Wait until the milder days of autumn before cleaning up any damaged leaves.

• Dust storms can make the garden look a real mess! While the dust can actually benefit the plants with the addition of micronutrients and minerals such as iron, it can impact on the plant’s ability to photosynthesise. Washing excess dust off the leaves will help.

Life is too busy for us to spend too much time nurturing plants that aren’t really suited to Melbourne’s weather. Replacing stressed out and struggling plants with hardier ones will make your life easier in the long run, and will be so much more rewarding!

Her'e’s a pick of a few of our favourite drought tolerant plants.