So....I've made a huge mistake.....regarding GRASS.....i'm an idiot!

[Zoisite]

Originally Posted by Thinking-man

Here's a picture of a leaf...and the seeds that f%&$ up the grass every fall.....literally thousands of these things fall down below.....

That looks like Beech leaf and seed pods. Beeches don't grow in my location so I'm not 'personally' familiar with them and their habits. But I believe there are at least 5 or 6 varieties of Beech, and I know that all Beeches have quite a high content of tannin in the leaves, roots and seeds. Too much tannin and acidic leaf litter on grass can effect grass and grass roots. You've already gotten some good advice about what to do with your grass, and I'll suggest that you sprinkle some lime onto the effected areas on the ground within and just outside of the drip line of the Beech tree.


Edited to add - Beeches are drippy trees. Here is a list of drippy trees:

Beech
Birch
Elm
Grape
Horse chestnut / buckeye
Linden
Maple
Mulberry
Oak
Poplar
Rhododendron
Walnut


.

[Reactionary]

OP - I'm beginning to believe your thread title...

It almost doesn't matter what tree you have, as long as it isn't an allelopathic (plant that kills other plants) tree like Black Walnut. However, if the tree is a beech:

It also casts dense shade and has an extensive network of shallow, fibrous surface roots that make gardening underneath it almost impossible.

https://en.wikipedia.org/wiki/Fagus_grandifolia

Gardening underneath the tree is "almost impossible" because the beech loves water and will suck up water that even shady grass needs to grow. If you have an irrigation system, you may be able to ameliorate the problem.

What type of grass did you sow and do you have an irrigation system? After all, you DID ask about GRASS...