I think you are playing with fire if you try to do it chemically! What zone are you in and how old is the plant and how big? Can you take some photos? Have you mulched or used ground covers under your bushes? I have more than 40 hydrangeas and grass is not a problem because the root balls are solid enough to keep out grass. If it is really a bad problem, then I would dig up the plant, wash off the roots and pull the grass out from the bottom. Make sure to pull any roots under the root ball and then pop the plant back in the spot where you lifted it. Don't be afraid to dig up a hydrangea - especially for a few hours. Be careful not to cut too many roots but most hydrangeas are pretty shallow rooted and easy to dig. After you replant - be sure to water well and you might have to add some new soil, but be sure to mix it well with the old soil. Mulch the plant well. The mulch will not only keep the soil moist but prevent more grass or weeds from under your hydrangea. Do not add fertilizer at this time - you don't want to encourage new growth that will be killed by the first cold weather.

As long as the yard grades downward, away from the house, there is no reason to be catching water near the foundation. (Doing that is akin to placing a drain high up on the roof. It would serve no purpose at all.) Yet pebbles/rocks/gravel invite water to penetrate into the soil, should there be any water there. I would get rid of all the rocks. They might have been used as landscape mulch. Some people are under the impression that it is a way to prevent weeds, but as you see, it's not. Getting rid of the rocks would allow you to develop hardscape and foundation planting in the normal, regular way.

As others have stated, it is pretty tough to get another floor to 'grab' a finished concrete floor like this. To get tiles to go down properly, you need to shot blast this surface, prime, then apply new concrete. Once that's done ($3-$5/sf) and all nicely leveled up, you can then look into adding tile. That's when the regular price of $12-$15/sf comes in. A floating floor is possible. A vapour barrier can be put down over the existing finish and then you float whatever you want over it...assuming the concrete flatness rating is good enough. If it isn't, you will need to get the flatness to a proper level (see the 'grinding/blasting' option). A stained concrete floor is notoriously difficult to get rid of once it's there.

Oh wow, I guess I don't have it so bad....orange stains on the house and fence that you have to avoid, that really is something I never heard of, but it makes sense. So, I wonder if you have ever considered drip irrigation. lol. I have had a fleeting thought about it, every once in awhile, but I think that about the vegetable beds more often. I have no idea why I haven't done it. I did put down some soaker hoses in some areas, but, I haven't used them in awhile. I need to check to see where they are again. Oh, I left them out one winter and they sprung a leak. I just need to replace them, and put them away in the fall. Soaker hoses I am a fan of, but not drip irrigation. I often think that I'm changing plants and shrubs in my garden too often to really get the benefit of 'permanent' drip irrigation. Then it would be one more thing to move. [g] But that's a great idea. That's what I need, is to buy some new soaker hoses at the very least. Thank you. :-)