Choosing the right garden mulch is one of the most important decisions you can make for the health of your native garden bed. Using the best mulch for native plants helps suppress weed growth, retain moisture, moderate soil temperature, and prevent erosion. This guide will explore the pros and cons of different mulch options to help you select the perfect mulch for your garden in Australia when it comes to natives. Unfortunately, its not always as simple as throwing your grass clippings around as mulch for your garden when it is the native variety.
What is Mulch and Why is it Beneficial for Native Plants?
Mulch is a protective layer of material spread on top of the soil surface in garden beds. Both organic mulches (like wood chips, bark, leaves, straw) and inorganic mulches (like stones, gravel, rubber) can be used. Mulching offers many benefits:
- Suppresses weed growth by blocking light that weeds need to germinate and grow
- Retains moisture in the soil by reducing evaporation
- Moderates soil temperature and protects plant roots from extreme heat and cold
- Prevents erosion by protecting bare soil from heavy rain and wind
- Improves soil health as some organic mulches decompose and add nutrients
- Gives beds a tidy, finished look that enhances curb appeal
These characteristics make mulch ideal for gardens. Native plants thrive in nutrient-poor soils, so a mulch that enriches the soil too much can cause native plants to struggle. Mulching helps create the well-drained, low fertility conditions natives prefer.
What Type of Mulch is Best for Native Plants?
When choosing a mulch for native plants, the main goal is finding an option that mimics the natural bush environment. Here are some top mulch contenders:
Wood Chip/Tree Mulch
Wood chip or tree mulch consists of shredded tree prunings and branches. This mulch:
- Breaks down slowly to provide long-lasting weed suppression
- Lets water penetrate easily while reducing evaporation
- Moderates soil temperature effectively
- Adds modest nutrients as it decomposes over time
Aged wood chip mulch from local tree prunings or your friendly arborist is an excellent choice for gardens. Try to avoid wood chips from diseased trees or treated timber.
Pine Bark Mulch
Pine bark mulch consists of shredded pine bark. It:
- Has an attractive dark reddish-brown color
- Decomposes very slowly so doesn’t require frequent replenishing
- Has a chunkier texture than wood chips for greater stability
- Contains tannins that help suppress weed growth
Pine bark is widely available in garden centers and works well for native plants. Opt for composted pine bark which has broken down more.
Leaf mulch like eucalyptus leaves makes a great native plant mulch when applied in a thick 100mm layer. Benefits include:
- Mimics the natural leaf litter in Australian bushland
- Breaks down relatively fast so needs regular topping up
- Lightweight leaves don’t compact the soil
- Adds nutrients as the leaves decompose
Collect free leaf mulch during autumn or purchase baled leaf mulch. Avoid using leaves from exotic plants or diseased trees.
Pea Straw Mulch
Pea straw mulch consists of the dried stalks and leaves leftover after peas are harvested. It:
- Has a light golden color that complements native gardens
- Is lightweight and easy to apply around plants
- Breaks down faster than woody mulches so needs replenishing
- Adds nitrogen to the soil as it decomposes
The added nitrogen can be a downside in native gardens. But used sparingly, pea straw can make an attractive mulch.
Inorganic mulches like gravel and pebbles have some advantages:
- Don’t break down so provide permanent weed suppression
- Come in a range of colors to complement different gardens
- Won’t blow away in windy spots
- Don’t harbor pests like termites or snakes
The disadvantages are they don’t improve soil health or retain moisture like organic mulches. Use gravel sparingly between plants, not atop entire beds.
How Should Mulch be Applied around Natives?
Proper application is key to getting the most out of mulch:
- Remove any weeds before applying mulch so they don’t grow up through it
- Apply a 5-10cm layer, replenishing annually as needed
- Keep mulch 2-3cm away from plant stems and trunks
- Spot mulch around each plant rather than blanketing entire unused spaces
- Top up mulch to the original depth whenever it starts to thin
Organic mulches like wood chips naturally decompose. To maintain their weed-suppressing powers, expect to add more mulch once or twice a year.
Where Can You Get Free or Low Cost Mulch?
Don’t want to buy mulch by the bag? Check out these free or cheap mulch sources:
- Council green waste sites often have free mulch made from shredded street trees
- Tree lopping services will sometimes deliver free mulch after big jobs
- Local arborists may offer cheap mulch from their tree pruning
- Farms may sell inexpensive straw bales after harvesting hay or silage crops
- Chipper days turn residents’ gathered green waste into community mulch
Ask first about the source of the mulch. Avoid street tree mulch contaminated by car pollution or dog urine.
Choosing the Best Mulch for Your Native Garden
To summarize, here are some top mulch options for gardens:
- Aged, shredded wood chip mulch from tree prunings
- Composted pine bark mulch for weed suppression
- Leaf mulch like eucalyptus leaves to mimic bush environments
- Pea straw mulch used lightly to avoid excessive nitrogen
- Gravel or pebbles sparingly between plants
Aim for chunky, coarse-textured mulches over fine options which can compact. Test different mulches in sections of your garden to see what works best. Proper mulching technique is vital – apply an adequate layer, maintain distance from plant stems, and refresh regularly.
With the right mulch, you can help your native plants flourish while reducing garden maintenance. Explore mulch choices for your patch of Australian bushland today!
Q: What is the best mulch for native plants?
A: The best mulch for native plants can vary depending on the specific types of plants and location. A common favourite among gardeners in Australia, specifically in New South Wales, is the arborist wood chips or eucalyptus mulch. This type of mulch provides numerous benefits such as moisture penetration and insulation which can positively impact the health of your plants.
Q: What are the different types of mulch that I can use?
A: There are many different types of mulch that a gardener can use such as lucerne, mulch made from woodchip, or even natural options like pea straw. Each type of mulching material has its own benefits and drawbacks so it’s important to choose a mulch that’s best suited to your plants.
Q: Can the wrong colour mulch negatively impact my plants?
A: Yes, the colour of the mulch may have an impact on your plants. Darker mulches such as black plastic or landscape fabrics can absorb heat and may negatively impact your plants by overheating them. Conversely, lighter colored mulch like arborist wood chips can add a natural look and feel to your garden while also reflecting heat away from your plants.
Q: How does mulch stop weeds?
A: Mulch stops weeds by acting as a blanket that covers your soil. This action essentially blocks sunlight from reaching weed seeds which can prevent them from germinating. Using a thick layer of mulch should be applied can be an efficient and organic way to stop weeds from growing.
Q: Is there a specific mulch to use as a termite repellent?
A: Yes, some types of mulch can act as a termite repellent. For instance, eucalyptus mulch has a natural termite repellent property that can deter these pests. However, always consult with a professional landscaper or arborist for the best solution for your termite problem.
Q: Can mulching material also act as a fertiliser?
A: Absolutely! Mulch like lucerne or humus can slowly break down, releasing nutrients into your soil and acting as a slow-release fertiliser. This not only helps in the growth and health of your plants but can also improve your soil over time.
Q: How does mulch help with bushfire resistance?
A: Mulch is a great way to help insulate your soil and retain moisture, which can be beneficial in areas prone to bushfires. Rainfall is absorbed by the mulch instead of evaporating, increasing soil moisture and making it more resistant to bushfire. However, not all mulches are equally effective. Eucalyptus mulch, for example, is less recommendable due to its flammability.
Q: Can using mulch encourage the growth of harmful micro-organisms?
A: Although mulch can provide a good environment for micro-organisms, the majority of these are beneficial to the health of your plants and soil. However, if you notice any mold growth or an unusual smell, it can be a sign that the mulch may be harbouring harmful micro-organisms, and should be removed or treated accordingly.