Best to leave them where they fall. No need to shred them.

Is your wooded area grass or natural? If it's natural I would leave the leaves where they fall or rake them into areas leaving paths clear. I put my all over the woods and then come spring we found we have to take a lot of it back out again and pile them up into a make-shift compost pile. The reason being that the spring wildflowers like dog-toothed violet, jack-in-the-pulpit and blue cohosh were having a hard time coming up through the thick wet mat of leaves we had piled on the woods from the grassed parts of the property. The leaves did well to protect the plants and shrubs over the winter so we will continue to pile them in the woods but in spring we will compost them and then re-use them as mulch and humous for the soil.

We live in the city too... just inside a old farm woodlot so our lot is average city-sized lot as well. :o)

Barb
southern Ontario, CANADA, zone 6a

Barb is right. The leaves to be wary of are things like maple that pile up flat and create a thick wet mat, those you should shred first. Things like oak that are fluffy just leave where they fall (Leaves, Fall, well that was almost a pun;o)

Hate to disagree with KWoods, but I feel that maples are fine to leave (ha, ha) and oaks should be raked and shreded. Maples are thinner and break down easier, while oaks have that waxy coating and they can mat and persist for years even. Just my .02
t

Well trilliophile, I happily and respectfully agree to disagree;o) In my experience Maple leaves mat together and hold moisture rotting crowns and preventing delicate plants and germinating seeds from emerging. If you shred 'em first (read "mow 'em over once or twice w/ the lawnmower") they don't mat together and hold as much water.

I googled looking for a few sites to bolster my argument and found some... BUT, in so doing I found an equal number of sites which supported your argument! Seems like there are benefits and problems with both As with much of gardening I guess it's best to gather the facts then figure out what works for you.

Here is an interesting site I found while on my leaf quest that gives a lot of the answers.

if you are trying to grow grass or other non-native plants under those trees the leaves should be raked, shredded and used as mulch or compost.

if you have woodland garden with native plants the leaves, whether maple or oak, can be left to decompose naturally as intended.

Ask yourself how much diversity of plant species you find under the type of trees you have in a "natural" setting. If that's what you want for your woodland garden leave the leaves, otherwise shred 'em.

In my opinion it would be a mistake to tell someone "leave the leaves" if they were something like Norway Maple or Black Walnut. Part of the reason Norway Maples are changing/limiting the diversity of species in our eastern forests and are so invasive is the thick layer of leaves which smother spring ephemerals and prevent understory species from germinating. Norway maple leaves also contain germination inhibitors (phytotoxins, as do some oak species, Black Walnut and others) for around 9 months until they start to break down and leach into the soil. Not good if you have plants you wish to reseed. This, in addition to shading out competing species, efficient seed dispersal and very thirsty surface roots, is why you are starting to find monocultures of Norway Maple in some eastern forests. (... as he decends from his soapbox ;o))

Anyway... I think you need to find out what type of trees you have dropping leaves and what kind of volume of leaves you are talking about before you decide whether to leave the leaves. Also, are you leavin' leaves as a mulch to keep down weeds or to add organics to the soil? As long as they don't create a thick mat you are probably OK but shredding them is the safe route in my opinion (which I'm certain I have overstated).

I think several people have hit the right point here: "it depends". In general, leaves left to decompose in place versus being raked, shredded and returned as mulch is a better choice. That is the natural way. However, depending on what kind of leaves you have, what the leaves are falling on, what your goals for the area are, how many leaves you have (a little or a lot), etc. ... you can see that the variables are many.

So consider these things, watch what happens and then decide for yourself.

I'm in the 'it depends on what the leaves are' category. Our previous house came with Norway Maples - those leaves are deadly to leave unchopped! Here we have Northern Red Oak, Green Ash and White Pines. All of those are more or less fine to leave as they are in my suburban backyard 'woodland'. The ones that fall on the lawn get chopped with the lawnmower and added to the woodland areas or used to help create new beds or top dress existing ones. Leaves - or pine needles- that fall directly into the woodland garden areas are left intact where they fell. My biggest weed problem in the garden is ash tree seedlings though! :-)

One additional point about leaves that fall on grassy areas. You don't have to rake them away before chopping them. Just run the lawn mower over them right where they fall to chop them up. Then they will break down right where they are and fertilize the soil. This works even for maple leaves, as long as the layer of leaves isn't thicker than a couple of inches (if it is, mow a couple of times as the leaves fall). The lawn will look messy for a couple of days or weeks (depending on how warm the weather is), but frankly I don't care about that, and this method is really the easiest and most ecologically friendly way to "dispose" of fallen leaves. You're basically just speeding up a natural process.

I'm firmly on the side of maple leaves bad, oak leaves good. My woodland garden is under a couple of huge norway maples. I leave the leaves alone in fall, rake them away (onto the lawn, where we chop them with the mower) in spring. Otherwise new growth cannot break through the thick, cardboardlike layers of wet leaves. And I don't think it's the leaves of norway maples that are poisonous to other plants. From my experience gardening with norway maples all around, I think it's the roots.

Here is a (I think) interesting PDF file on tree allelopathy. Norway maple's listing is based on a 1969 study. It lists Norway Maple in the section "Moderate" and lists pathways as "roots/leaves".

It also lists a lot of other trees that I would not have known use allelopathy to gain a biological advantage.

I don't think the phytotoxins in Norway Maple leaves are as important a factor as the matting and moisture retention when deciding wheather or not to leave the leaves. I also think they're impossible to grow under because of the thirsty roots more so than any allelopathy. Who knows, information is great but experience is reality.

We rake, mow up the oak leaves on the grass. Other wise the grass would suffocate and DIE, mulched or not. We get leaves easily a foot deep in the yeard if left. We dump the chopped up leaves all deeper in the woods. The piles disappear by June. I rake out my wooded garden as soon as the snow/ice are gone so my plants can come up easier. While the leaves MAY be nice mulch, they harbor SLUGS, my ground covers would not show and I hate the messy look.

So in a big area that is part of a clean up project, would you take a lawn mower directly into the woods in order to shred the leaves? Slightly different twist than my other recent post....

After I chop up the maple leaves, can I incorporate them into my vegetable garden without inhibiting the growth of the veggies next spring?

I have two acres of mostly burr oak. We collect the leaves that fall on the grass and spread them deep in the woods beyond my garden beds. I used to spread them on the gardens but that meant lots of spring raking due to too deep of leaves for the plants. Spreading them in the deeper woods keeps the unwanted weeds down. I cannot take a lawn mower into the woods. The stumps and sticks would wreck havoc on my blade. I am happy to smother the weeds. Your vegi garden will love your leaves. I dig what leaves I can in each Fall. If I owned a tiller I would use that. In the spring when you till the garden the leaves will be mostly gone and a wonderful addition. When I lived in the city and had to pay a guy to come till he charged me extra to work in all the leaves, it takes longer...

WOW, I just found an old post of mine. See how I have changed over three years!!