Get a magnifier and look for mites on the affected leaves.

Otherwise this is a huge growing kind of rose that does well in hot climates, I hope the designated planting site is up to the task.

https://tombstonerosetree.com/worlds-largest-rose-tree/

I did embothrium,
But there’s no mites..

The last time I’m fertilizing all of my flowers is in the middle of june

Really looks like it has a sucking pest infestation to me. Try clipping samples and taking them to an independent garden center for comment.

The darkening could possibly be honeydew fungus, growing on sucking pest secretions coming from above the affected leaves. Such as from an overhanging tree or shrub, that is infested. If so it will be primarily on the up-facing rose leaf surfaces, where the dripping hits. While this is actively occurring leaves so affected will usually appear glistening and sticky. However maybe you had this happening earlier and now the bugs are gone, but the visual effect produced by the fungus lingers.

Again what is needed is close in person examination. Don't undertake any chemical applications or other remedial action until the problem is positively identified.

There was a previous post duplicate to this one that now seems to have vanished. I had commented on that one and my thoughts were also sooty mold (the honeydew fungus) or a mite infestation. btw, the mites are tiny enough that they cannot be seen easily with the naked eye....or even on the plant itself with magnification. Pluck off one of the affected leaves and shake it firmly over a clean white piece of paper. If any mites present, they will show on the paper as very tiny little dark specks.

Hi @embothryum @gardengal..

Now I remember..
in the middle or last May or last first June, there’s a lot of ants on my lady banks leafs
But I don’t know why..
Right now all of the ants gone..

If it’s sooty mold or mites
What should I do??

The ants were there because of the sucking pests - or vice versa. If they have left probably the pests are gone now also, with the current sootiness a leftover of that episode.

Again you will have to make your own close examinations and/or seek local guidance in order to determine what, specifically is happening at this time.

That will dictate what, if any steps are to be taken now.

Can I spray the leafs with insect soap?? For mold and insects
If it’s can I’m gonna order now from amazon

No, insecticidal soap is potassium salts of fatty acids, which is LARD. Spray that on the foliage with the extreme heat you are having and you will burn every leaf. If that is sooty mold (which I think it is) you may try rinsing it off with water. It will probably take several times doing it to loosen the cooked on sugar and mold but it will eventually start to come off. Otherwise, don't worry about the sooty mold. If you have no ants, there may not be active mites. Just wash the tops and bottoms of the leaves and you will take care of much of the problem and make the rose much happier in this heat.

And here you go again..
Thanks for your advices,
As a beginner gardener, I really needs some advices, and learn from the expert..

Before there’s a lot of ants on my lady Banks leafs, by the end middle of June
But after that, there is no more ants anymore right now..
I’m gonna rinse off every day only by watering them..early in the morning

Again, thank you so much RoseSeek ❤️

You're welcome! You probably fed this the Bayer 3 in 1, right? That pesticide likely killed off the ants. The next time you go out shopping in the garden department,look for a water wand. It doesn't need all the adjustments for the water flow, just a long enough pipe to be able to stick the water inside the plant and wash off the under sides of the leaves. The plants will thank you for it!

I will roseseek
Thank you
Thank you
So much!!!!!
❤️❤️❤️❤️❤️❤️❤️

You're welcome!