Black walnut has something called juglone in it, and it's supposed to supress plant growth. I'm not sure, but I think composting alleviates the effects.

Never had any problems with black walnut as leaves,shavings or sawdust,in compost.
But I haven't mulched with it.
Otherwise I use everything this area produces in both compost & mulch.
Oaks,maples,birch,cherry,tulip,sassafras,ash and some other Eastern hardwoods.

I've heard of some people avoiding leaves that contain too much(many?) tannons (sp).
I don't remember which leaves those were, but I've got smaller more trivial things to worry about (8D).
I compost at random~leaves~grass clippings~horse poppers~straw~old cardboard~new cardboard~food stuffs~deer, whatever happens to pass within my grasp and not get away, gets composted.
I feel the more variety in the compost the better.

There are still people out there that believe that certain tree leaves will change their soils pH and they will not use them. Around here that is a benefit for me because I can use those for my garden, if I get into town to pick them up. The only way any leaf might, possibly affect your soils pH is if you dump tons of them on all at once, and work them in.

I have a mammoth tulip tree, and that's what started me composting...to help manage all those leaves. Now I'm a compostin' fool.

At night when I'm going to sleep, I THINK ABOUT MY PILE. This is what y'all have done to me. I'm obsessed with my pile. (And I've only been composting about 3 or 4 weeks...LOL, I hope I calm down eventually)

And now, my new word of the day, allelopathic: A plant that produces chemicals that kill off surrounding plants as a defense mechanism. Thank you Google.

Hi all, thank you very much for sharing! It is really appreciated!

The town I live in is COVERED in Eucalyptus trees. In my experience, they take FOREVER to break down, and are apparently highly acidic so I usually do not put them into my bin.

I came here today to ask this very question, only I want to cover a freshly tilled vegatable garden with mulched leaves. I dont have a worthy tree in my yard to get leaves from. I have a chinese tallow and it seems like I read somewhere that its leaves can negatively effect the soil. I would like to find a leaf source that breaks down quickly as well to cover my new garden area until spring.

Duajones, maple leaves probably break down the quickest.

Deanna

Don't use posion ivy leaves.

I have the very same question.what about sumac? how about sycamore? I have sumac on the border of the property and it always blows in my maple/oak/apple pile.It's NOT the poison type.what about the sycamore? I know the insects leave it alone.

Walnut, ailanthus and norway maple can all be aleopathic but I suspect if you let them rot for a year or two in their own separate piles they wouldn't be so bad.

I'm not good at identifying trees or leaf types and I compost or mulch with any old leaves that come along. Sometimes ignorance is bliss.

I don't think there are any black walnut trees real close by, though, because I never notice those ugly green blobs laying around on the street.

Karen

Any leaf that does not absorb moisture as readily could be said to not break down as easily as others.
Oak leaves for instance, are recommended for when leaves are used as insulators....as for a hydrangea, since they do not absorb moisture as readily.

But how much is too much? How fast is fast?

Unless a ton of leaves is poured into a compost pile...???
How is one to know whether enough is enough.

A compost pile is best when not too much of any good thing is put into it. A balanced diet is good for us....and for a compost pile.

Chewed up, the leaves, any leaves, will break down....and all that concerns is how fast will it break down.
Some do that better......but if we are not in any too much of a hurry, the leaves will do their part.

Since a compost pile is a rather small amount of garbage, a change of pH might be attained by a ratio of something that could cause such change. How much oak leaves does it take to change a pile's pH....one degree....two degrees...
i.e. 6.5...6.0 Or 7.0....6.0.

Given that the pile may be small in relation to the amount of the changing matter, wouldn't it be possible for such amending matter to have a greater degree effect on such volume.

If nothing but oak leaves were put into a pile, whatever else is added, wouldn't the tannen in such leaves have a greater effect than .....say adding maple or birch leaves.

Magnolia leaves take years to break down unless put through a shredder. I have some on their 3rd year that still have not broken down. I'll never steal them again.

Generally UK gardeners are advised not to put large quantities of fallen leaves in their compost heaps on the grounds that they cool the compost and do not add much in the way of plant foods. We are recommended to make leaf mold instead. All this needs is a simple cylinder of wire netting and time. My local council collects leaves from the parks and piles them up in large three sided containers made from wooden planks situated on all the city's allotment sites. (Community gardens). We just help ourselves to whatever we want for soil conditioning or mulching. I spread leaves every autumn around my soft fruit and also cover any beds which have nothing growing in them over winter. We get maple, oak, ash, beech, chestnut and horsechestnut and a wide variety of ornamental shrub leaves. Holly is a bit slow to decay and the prickles go last. Laurel, bay and magnolia are also slow. But if you make leaf mold it doesn't really matter because after the first year you will always have heaps in various states of decay from ready to use to brand new. Possibly conditions for many of you are different eg our compost heaps seldom ever freeze, eeven slightly, so leaves may break down slower, but I think leaf mold is worth thinking about.

In the compost facility we composted large quantities of walnut without any problem after they were composted. They were always mixed but in some cases the percentage was quite large.

Whether any leaf will get digested and how quickly depends on many things not at all related to which type of leaf it is. The ratio of N to C, the moisture in the mix, the volume of the pile (to a point a larger pile will get digested faster than a smaller pile), and whether there is enough air for the bacteria to use.
Compost will finish with a pH around neutral, or at least it has for me for over 40 years except when it went anaerobic on me early on. For questions about composting refer to the link below, but be not afraid about using what leaves you have. If the C:N ratio is close to optimal, ie. 30:1, all leaves will compost and will be good for the soil.

Here is a link that might be useful: Florida Composting Online