Lots of leaves

Sunday, 25 May 2014

Pile of liquidambar leaves at the bottom of my garden

The incredibly (almost scarily) warm, dry weather we have experienced this month seems to have prolonged the display of autumn foliage everywhere this year. But the leaves are starting to fall, cloaking our gardens with a transient layer of colour - which I enjoy. However, there comes a time when they must be tidied up, and different gardeners have their own ideas on what is best to do with the leaves. I seem to have been haunted by fallen leaves this week, having spent a considerable amount of time raking them and sweeping them up. So I have had plenty of time to think about the value of deciduous leaves in the garden and how to deal with them.

It's hard to believe that once upon a time people used to burn autumn leaves to get rid of them! In our garden, all large deciduous leaves are raked into a pile, fed into a mulching machine then put onto one of our compost heaps, which also gets lawn clippings and mulched-up prunings of woody and semi-woody plants (and the occasional bag of manure). The pile is not turned (except by the resident brush turkeys!) so it does take quite a long time to break down. But when it has, the result is lovely dark compost like rich chocolate cake, which I use as a surface mulch or dig in when improving the soil before planting a new specimen. However, some people use the shredded leaves immediately as a mulch on flower beds, which is a good idea if you don't have a compost heap. One good tip I learned this week from a friend is to rake the leaves onto a large tarp then drag this to your compost heap or garden bed.

Liquidambar leaf

Shredding large leaves really does hasten decomposition: many of our leaves are from a large liquidambar tree (Liquidambar styraciflua), and they take much longer to break down if just piled up whole. Shredding also reduces the volume of the leaf pile as well. Another way to shred autumn leaves is to mow over them and add this material to the compost heap. Smaller leaves can simply be raked up and added to the compost heap or put around shrubs as a mulch, which I do with leaves from our crepe myrtle trees and Japanese maples.

Japanese maple in my driveway

A different idea is to place leaves in aerated plastic bags with a bit of blood and bone, and stow these away in the garage or garden shed. The leaves are supposed to break down into superb leaf mould, but I have to say that when I have tried this, all I had after a number of months was a bag of dry leaves. I think I did something wrong! However, the idea still has merit even if the leaf mould doesn't happen - these leaves can be shredded in summer and added to the compost heap when there is an abundance of 'green' (high nitrogen) material such as lawn clippings and soft prunings going into the heap, and little of the dry 'brown' (high carbon) material that is needed to form a well-balanced, actively decomposing heap.

If you don't have deciduous tree in your garden, there are a number of reasons for adding one: the beauty of colourful autumn leaves and the pretty carpet they make when they fall; the benefits of the leaves in enriching your garden soil once they have fallen from the tree and broken down; the extra sun that your garden will receive in winter when the tree is bare; and the excitement of seeing new buds in spring, opening up to perfect baby leaves that will go on to provide summer shade! For Sydney gardeners, refer to my previous blogs written in May 2009 and 2010 for some suggestions for suitable deciduous tree for our climate.

Reader Comments

  • By noeline 2081 Monday, 26 May 2014

    How timely your blog is, I just raked up 3 large heaps of leaves today and bagged them Deidre. I was watching gardeners world on tv and they say to soak the leaves in the bags and let them drain before storing them so I am hoping they turn into lovely leaf mold it is described as Gardeners Gold :) Thanks for that tip, Noeline. The added moisture would certainly help them to break down. Hope it works. Deirdre

  • By margaret 2122 Monday, 26 May 2014

    Begonia plants particularly enjoy the benefits of leaf mould. I rake and collect the leaves from my crepe myrtles, add some manure, and place in large plastic bags, for future use. The leaves do often take a long time to break down, but the plants respond well to the mulch, whatever the state of decomposition. The manure would certainly help the breaking down. I think the smaller leaves of the crepe myrtle would also break down faster than the large liquidambar leaves. Deirdre

  • By Jan 2582 Monday, 26 May 2014

    Can"t wait until our trees are big enough to worry about what to do with leaves :-) It is amazing how quickly time passes and before you know it, your trees will be tall! Deirdre

  • By Christine 2429 Monday, 26 May 2014

    Don"t forget (before you rake them all up) to walk, run or jump through them just to enjoy the rustle of the fallen leaves!! We have just so many, as we have a Plane Tree, planted 23 yrs ago,which is now enormous, doesn"t colour up much of course, but this year has been a glorious golden. 2 Lipstick Maples (young)have coloured up too, plus crepe myrtles, liquidambers etc. - a year by year thing in our warmer climate on the mid-north coast of NSW, albeit inland. Yes, such fun to play in leaves. A trip to Mt Wilson in autumn and playing in the fallen leaves was a highlight for my girls many years ago. Great you"ve had good autumn colour this year. Deirdre

  • By Carole 2230 Monday, 26 May 2014

    Ahhhh, thank you for the memories Deirdre. These days 95% of our leaf drop is eucalypt year round. If I see a few autumn leaves I just admire them and by the time I have thought of sweeping they are gone :-) Yes those eucalyptus leaves can be a challenge! Deirdre

  • By Gillian 2073 Tuesday, 27 May 2014

    I always enjoy Sydney"s brief fling of autumn colour. The deciduous trees are such a bonus in the city. Summer shade, winter sun, free mulch that only drops once year. (I have to rake up under my eucalypts 365 days a year!) The reduction in energy use that they can supply is enormous. We should be planting more! Thanks, Gillian. I agree we need more deciduous trees! Deirdre

  • By Richard 2112 Tuesday, 27 May 2014

    This is my first autumn without vast quantities of leaves, after my liquidambar gave way to an extension! I pile them on the lawn and mow them, greatly reducing volume, then store in compost bins where they eventually produce the wonderful compost you describe. I also hold back a few bags of leaves, which I spread on the lawn each time I mow in summer - a lazy way of getting the carbon/nitrogen mix in my compost! This year I will be relying on my aunts liquidambar for my leaf requirements! It is certainly a huge job raking up liquidambar leaves! Ours have almost finished dropping now. Deirdre

  • By Steve 2230 Tuesday, 27 May 2014

    I"m not sure what to do with my spore ridden fallen Frangipani leaves, I"ve read conflicting advice. One that you collect and dispose of in a plastic bag, and alternately to ignore the fungus spore and use as usual because it will come back next year anyway and is fairly specific to the Frangi anyway and will do no other harm. What do you think Deirdre? It is quite tricky. I usually put those sorts of leaves in the green bin to be on the safe side. Deirdre

  • By Robin 2121 Tuesday, 27 May 2014

    From past experience I have found that the bags of fallen leaves do need some moisture in them, along with blood and bone and/or manure, to help them break down. I have been told that worm wee or male urine aid decomposition but have yet to put that to the test! Thanks for these tips, Robin! Deirdre

  • By Sue 2074 Thursday, 29 May 2014

    I agree with Robin - I pile them in garbage bags, prick holes in the bag, add B&B, manure and make them very wet.Leave them in a pile for months, then tip them into a compost area and covered them with shade cloth giving an occasional wetting to keep moist.Its been a year and the humus they have now made is good enough to eat:-) Well worth it if you have a spot to plonk them for a year. Thanks, Sue - I will try this method! Deirdre

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