Soil Acidity Question and When to plant

Soil Acidity Question and When to plant

I have a large oak tree in our backyard along with several beeches, ironwoods and a Norway maple. Underneath them I was planning on putting in a woodland garden next year. I read that oaks are acidic and I see that because no matter the type of seed we put down, no grass ever grows beneath it. I was planning on putting leaves in the beds during the winter/fall to better amend the soil. I was wondering if any of those trees' leaves or any other low-cost solution would help benefit the soil to less acidity? Or, do you think it not matters since it will be a woodland garden and the plants could tolerate high acidity underneath an oak? Also, would fall be an ok time to plant miniature roses? I was wondering if I want them to overwinter in the ground and I didn't know with the cooler temps here (it was 56 today!) if now was a bad time to plant the roses.
first time winter garden

first time winter garden

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plant ID halp?

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Tomatoes in trouble ?

Americanized room in Osaka

Americanized room in Osaka

A new visitor in my garden!

A new visitor in my garden!

plant ID help, zone 9

plant ID help, zone 9