Seeking advice for improving quality and quantity of peach tree yield

I'm in my 4th summer in my current house. I have two smallish (maybe 10 feet tall?) peach trees in the back yard, about six feet apart.

Tree A: first 2 summers, it bore marvelous peaches. Picking them and eating them on those hot sunny days in August is among my top 20 life experiences. The third summer, it bore far fewer peaches and the quality tended to be much lower. This year it has peaches, though they aren't ripe yet. I'm nervous about how they'll be. In the late spring many of the peach buds fell off, and I'm not sure if this is a bad sign or if it's normal and I just hadn't noticed it in previous years.

Tree B: has always produced a prodigious number of peaches, but they have always been hard and rather sour/flavorless even when fully color-ripe. Basically they're inedible. I did notice that did not lose peach buds this year the way its sibling did. Tree B, it should be noted, has a rosebush growing at its base (beautiful and fragrant pink roses!) as well as a lot of spearmint (which I love and use in my cooking).

Both trees are planted along what used to be the edge of an in-ground swimming pool that was removed, filled in, and covered with dirt and grass long before I moved in. Other than a conspicuously rectangular flattish area in my yard, and an extra sub-panel in my garage, you wouldn't know there was ever a pool there.

This week I'm planning to remove the grass in about a 3-foot (1 meter) radius circle under Tree A and put down bloodmeal, then cardboard, and then mulch, to see if that improves the peaches at least in a year or two. Do you think that's a good idea? What else might I do?

What about Tree B?

I certainly don't consider myself a peach tree expert, but I do have one. I have to hand pollinate it in my zone, and protect it against the side of the house. However, I agree totally that there's nothing better than home grown!

OK, everyone says grass is lousy ground cover under trees . Here many orchards have embraced dandelions because they're so important for our pollinators.

I've observed that my peach tree *really* likes lots of water. We give it the water used for washing eggs from Hubby's egg business, so water and fertilizer in one. That worries me about cardboard mulch as it might stop water infiltration in the short term, even if it improves it in the long term.

I've also found that trees that are encouraged to broaden their root system seem to be happier and healthier. To encourage this, I'm known to dig holes a foot past their drip line and fill the holes with all sorts of compostable goodies. So kitchen scraps, chop and drop weeds, chopped up cardboard, biochar, punky wood. This helps water infiltrate deeply, and earthworms to come and loosen the soil, and the roots to have a reason to spread out. Narrow holes like can be made with a post hole digger are awesome in the right soil and can be helpful as much as 3 feet deep. Alas... not happening in my clay/rock soil. I generally don't get far before it's a rock removal process! Occasionally even a, "Hubby, I need you to fire up the rock drill - this is going to take the feathers and irons to get out!"

I have also tried mushroom slurries or micro organism concoctions from compost tea poured into the filled in hole to spread that sort of goodness.

I would totally go for a multi pronged approach. Our weather patterns have been shifting to colder colds and hotter hots, so anything that can make our trees more resilient is good.

As for Tree B - I'd graft it with something better. Many trees like unrelated friends, so I'd try to find someone else with a peach tree that tastes good for the donor. If you were #2 Son, you'd be pushing for grafting on a Nectarine - he prefers less fuzz and is OK with less sweet.