Fix border

Is it the area with the reddish edgers that you want to work on?

When you say 'fix', what exactly is your goal?

Do you want the whole area covered with concrete, do you want grass, flowers, etc.? Please tell us a little more about what you are hoping to achieve so that we can offer you suggestions that may work in your particular situation.

Also, a larger photo showing how the area in this picture relates to where the pool is would also be helpful.

Need more photos and better explanation on what you want to do

Plantings around swimming pools have more variables.

no one wants rain nor over-watering muddy run off in the pool, nor the pool deck.

What is your objective?

Where does excess moisture drain “to”?

I agree that "we" need more photos and a better explanation of your goal. Seems you want to "easily" just plant in the grass area. You can dig out the grass, replace with garden soil and plant directly into the ground IF the chlorinated pool water does not drain there. Otherwise, I'd recommend you put ground cover ("strong" spreading ground cover, decorative rocks, additional pavers, etc.) and plant in large pots. They are easier to care for and have better chance of survival than next to a pool. 😎

There are different garden border ideas here:

https://www.hometalk.com/search/all?filter=garden%20borders

I would make sure you move the border pieces you have or make new borders so that the water and debris from garden doesn't run into the pool.

There are some landscaping around a pool ideas here:

https://www.hometalk.com/search/all?filter=landscape%20around%20pool

I want to change border and put mulch on top of grass so i can put a planter on top

Are you looking for different kind of border ?

Thanks for the additional information on what your goal is.

Since grass is already growing in the specific area that you want to put mulch on, if it is not dug out/killed completely first, then it will continue to grow up through the mulch.

-Kill the grass completely first.

-Lay down landscaping fabric. The thicker the fabric and the more the individual pieces overlap each other, the more effective it will be at preventing the weeds/anything else from growing up through it.

-Cover the landscaping fabric with a thick layer of mulch.

-Put your planter on top the mulch.

As others above have noted however, the mulch will have to be replaced, simply due to the wind blowing some of it away, sooner or later. It will also be hard to keep the mulch from creeping on to the concrete when it rains, or when the concrete is washed.

For these reasons, I would recommend instead of mulch, that you put down pea gravel over the landscaping fabric. It holds its place much better than mulch, will be more efficient at keeping the landscaping fabric anchored, and there is little erosion after rain, or being watered.

I would also remove the red scalloped bricks. If the whole area is covered with pea gravel, the bricks will no longer be needed to hold the grass back. They are too attractive to just be wasted being covered up. Use them somewhere else in the yard where they will be seen.

I think it depends on what you're looking to plant. You can remove all the weeds and keep the borders where they are or dig them up to reconfigure then go from there.