Shredded leaves can make a good mulch but whole leaves are not recommended. Whole leaves tend to make an impenetrable mat that inhibits water and don't decompose- they'll still be sitting there next spring. Also many pests and pest eggs will overwinter in the layers they provide.

We blow ours out of all the beds, shred them, and return them- it's one of my favorite mulches for the natural appearance, the texture, and the ease with which they break down and enrich my soil.

welcome .....

where are you ... does your ground freeze???

what kind of leaves ... some can form mats that are anaerobic ... not allow air movement to the soil underneath ... like wet heavy maple leaves ... and then next spring.. you find the grass nearly dead under ... oak are the opposite .... what we need to figure out.. is if you are SIGNIFICANTLY changing the soil above the roots.... will it impact the trees???

and how old are the GG.. that you say are mature .... how big are they ....

and how deep are the leaves ... will they stay where they are.. or will wind blow them back out??

a pic or two might help us understand the setting ...

in nature... leaves blow around.. until they are blown into a spot where there is a wind dead spot .. and it is all natural.. and probably not a problem ... the base issue here.. is how your method might be outside the bounds of how ma nature might have done it ...

pix?

ken

I live in the land of the bigleaf maple.....and they mean big!! Leaves 15-18 inches across! They never get shredded, just blown off the lawn and into beds or the surrounding greenbelt. And when you think about it, no one is shredding the leaves that fall in the woods either :-) After umpteen years, I have seen no ill effect by leaving the leaves intact. Provided they are not fleshy, heavy textured evergreen leaves, they will all get smooshed up by wind and rain over the course of the winter.

Shredding is great but I would not consider it a requirement!!

I always intend to shred, because I have encountered those slimy mats of leaves. However I virtually never do it because of laziness, no time, etc. And I haven't had any problems, even with fairly large leaves like Catalpa, Cercis, etc. I'd just make sure that the leaves are not piling up around the trunks.

Mainly maple leaves here and they get raked into my conifer beds every year without issue.

tj

i wonder if the anaerobic possibility is a frozen soil issue??

who has left a pile of leaves on a lawn.. and come back in spring.. and the grass is smothered.. and barely alive???

ken

All of us

gardengal , our pres. says we should rake the forest

ron

I shred the leaves before mixing them in with cedar mulch only to speed up the process of decomposition and make sure that I don't create too much of an anaerobic environment. To the OP, I'd assume the wind will eventually blow some of the leaves out and what remains would be like a forest setting l, so not too much of an ill effect.