I've heard here and there that the leaves of some trees are poisonous to plants and can stunt growth.

Which leaves have you heard about "here and there"?

Black walnut leaves can inhibit growth, but they're fine if you compost them first.

About the only leaves I would not compost would be those from Poison Ivy, Oak, or Sumac. Some people think that the leaves of the Black Walnut (but apparently not any of the other from a the Juglans species) are harmful. That is something I have not seen any evidence of unless you count the fact that those leaves, alone, unmixed with any others, seem to suppress the growth of Quack Grass while they encouraged the growth of Perennial Rye.

I know from experience that trying to compost oak leaves is like trying to compost plastic chips unless you have access to really HOT manure.

And even then they have to be finely shredded.

They aren't bad for the plants. They just have so much tannin in them that they are decay-resistant.

I love oak leaves! I compost tons of them. My next door neighbor, who has 2 huge pinoaks, saves all his leaves for me. They don't take all that long to break down. They sure get consumed a lot faster than straw in my compost!

Karen

Yeah oak leaves compost great so long as you shred them first. I shredded most, but not all of mine. The shredded leaves fully composted before spring in the compost bin, but the whole leaves were still pretty much intact.

I had piles of shredded oak leaves that were mixed with kitchen scraps, grass clippings, and goat shed manure then turned and carefully moistened diligently for the first summer but which were still visibly chopped oak leaves after 3 years.

And they were already 9 months to 4 years old when I built the piles because the house had sat empty a long time when we bought it.

The oak leaf dust on the lawn from running the mower over all those leaves never really seemed to become one with the dirt either. If the weather was dry for a week, even at the very end of summer before the next crop of leaves was about to fall, the mower would kick up clouds of fine, brown, dust that smelled and tasted of oak instead of dirt.

It was so bad I had to mow with goggles and a damp bandanna over my face.

I'm sure you can compost oak leaves if you have a LOT of very HOT manure to mix them with. But in an ordinary pile of yard and garden waste its not so easy. They are as bad or worse than pine needles.

People collecting others' bagged leaves should go easy on themselves and look for yards full of maple instead. :-)

I wouldn't compost poison ivy either, but its certainly possible.

Shredding leaves makes them compost faster. I love using shredded leaves as mulch, so they rarely make it into my compost pile.

The primary mulch at my house is shredded oak leaves.

Black Walnut leaves do contain jugalone that can inhibit the growth of certain plants... not all plants are susceptible, tomatoes are particularly susceptible. I have composted black walnut leaves, but they were well mixed in with the leaves of many other trees. Once decomposed the jugalone is reduced to its basic chemical components of carbon and nitrogen and is no longer jugalone. (The same would be true for poison ivy)

Thanks for the replies. lazygardens, there was a list of leaves to stay away from but I think most of them were being over-precautionary. Black walnut and oak were the ones I was concerned about.

I thought oak leaves might be toxic since people say not to use the wood in the garden (maybe I'm confusing it with another wood) but I guess it's because it takes so long to decompose. It's interesting that different people had different experiences with composting oak leaves, I'll have to try it out for myself. Maybe some people let their leaves leach through fall/winter while others just gathered them in fall?

applebuilder, there is a very persistant old myth that Oak leaves are too acidic to use in the garden. However, if one pays attention to what reserchers discover over they years one would know tha the pH of maple leaves is 3.2, that of Oak leaves is 3.7 (slightly less acidic then maple) and all of the tree leaves we can get are in the same range, between 3.0 and 4.0. Oak leaves do have more tannic acid (a preservative) than others but they will compost just as well as any others as long as the composting rules are followed, enough N to feed the bacteria that digest them, enough moisture to allow those bacteria to work but not so much that they will not, and enough air to allow them to work.
Some people that improperly store leaves over the fall and winter, allowing the nutrients in those leaves to leach out and wasting those nutrients, are not making good use of a resource. Leaves just piled up can become Leaf Mold which is an okay soil amendment but just will not have the nutrients that compost will.

It's not a bad thing if some vegetable material is still visible in the compost, so don't worry about a few oak leaf shreds.

I don't compost the cactus pads ... the spines last forever in there. Everything else, including oleander goes in the heap.

The oils from poison oak and ivy and sumac might survive composting enough to make toxic compost: best to not risk it.

Bear in mind how many oak species there are when assessing any leaf qualities.
Pin,black (red in the lumber trade),white and chestnut oak in the N & NE will not be the same as southern oaks.
Black walnuts throughout their range will contain juglone.