Putting your leaf litter to work

Leaf litter is gold for gardeners. Here’s how to make the most of leaf fall in your garden (or local park!) this autumn.

The success of Amberwood, a lush and lively Tauranga garden, comes down to the dedication of homeowner Heather Loughlin, who has nurtured it from a bare section into a leafy, biodiverse world. It’s now loved by all manner of bugs and birds – and has many human admirers too. 

Despite being just 708m2, Heather’s garden is home to 52 trees, most of which are deciduous. With autumn setting in and leaf rakes emerging from the shed, we asked Heather to write about how she uses leaf litter to build up rich, nourishing soil.

Heather Loughlin of Tauranga’s Amberwood 

There’s more to leaf litter than you think

Leaf litter is nature’s way of feeding the trees and nurturing the plants in their surrounding habitat. When the leaves rot, they enrich the soil and provide an environment for all sorts of insects – a safe haven to dwell beneath and breed in. 

Fungi, mosses and lichen are all helped by this carpet of nutrients which traps water beneath it and prevents the soil from drying out. In turn, wild birds will scratch at the leaves and discover their food source – slugs, snails, insects and their eggs. All these creatures continuously aerate and fertilize the soil, a wonderfully clever balance of life.

In the native zones of Amberwood where she is recreating natural habitat for wētā, Heather mulches around the shrubs with whole leaves and adds rotted twigs as mulch.

Recreating Mother Nature’s recipe

I discovered that when the leaves dropped from my deciduous trees, they took quite a while to break down, and would often hold mould and fungus. This was not ideal for my plants, despite all the other benefits.

Another downside was that the leaves coated the garden paths, making them slippery and dangerous. I did some research and learned that if you break down the leaves, they are absorbed faster into the soil without encouraging mildew to the same extent as whole leaves.

My method for the best leaf litter

Step 1.  Prepare your planted beds by weeding and removing all dead foliage and flower heads. Dig and divide any plants that are getting too big. Clear the soil of any unwanted debris.

Step 2.  In dry weather, gently rake the leaves off the plant beds and clear all driveways and pathways of leaves. Wheelbarrow them onto the lawn and keep going until they have all been collected – the mounds may be vast! Rake the mounds as flat as you can, all over the lawn.

Step 3.  Put the lawn mower on the highest level and mow over the leaves with the catcher on. Each time the catcher is full, empty it back onto the lawn, and continue with the lawn mower on a lower setting each time. Twice or three times should suffice to get the leaves small enough.

Step 4.  After the final mow-over, carry the full catchers over to your garden beds and spread the mulch around the plants. Be careful not to pile too close to the stems. Using a hoe, you can gently mix this lovely mulch into the soil if you wish. Your lawn will also benefit from the tiny bits of leaves left behind.

You may need to do this two to three times during autumn, especially if you have a lot of deciduous trees like me. Then you can sit back and watch your garden burst into healthy life in the spring.

What happens to your soil after mulching?

Your soil will now be enriched to support garden growth without the need for added compost. However, buying in a little fertiliser gives the plants an extra boost. Work it into the rich humus to provide any minerals that may be missing.  

Everything lives in my mulched garden – wonderful giant leopard slugs, and yes the odd snail and common slug. However if plants are healthy, there is absolutely no need for sprays or blanket slug bait. I do use a nature-friendly slug bait around hostas, but that is all. The shredded small leaves may well deter slugs and snails at your place.

Millions of insects dwell hidden, until something is moved and reveals their communities. Cockroaches, yes! Wētā, yes! They all have a role to play. Look after them and they will spend their entire lives caring for your garden, day and night.

What type of trees work best?

Deciduous trees are – of course – best, as they drop their leaves at the right time and all at once. Non-leathery, soft leaves work well and are easy to mow, such as birches and maples. Once the whole garden is mulched this way, it looks fantastic, thrives beautifully and smells divine!

By summer, all of this wonderful leaf mulch gets absorbed into the soil and looks like it was never there. The telltale signs will be in your strong healthy plants though. 

The beauty of densely planted deciduous trees is that they provide exquisite shade all summer long, and stop the soil from drying out too quickly. In winter, the bare branches permit the sun to shine through, encouraging the further breakdown of the leaves and the new growth of plants. Isn’t nature just marvelous?