Your tree is Vitex agnus-castus, Chaste Tree. As laceyvail says, all flowers fade, so that's normal. Watering with a sprinkler is inefficient and wasteful. It would be better to run a hose near the base for a good while but less often, if you really think it needs watering. They are actually very drought tolerant. However, since we don't know your location it's hard to say. And yes landscape fabric is a bad idea.

the plants is lacking proper water.. because someone interfered with gods plan.. and put a plastic fabric between the plant and the sky.. remove it yesterday .. period ..

roots need air as much as water.. and the plastic also interferes with air exchange ...

its just a no win situation ..

after disturbing all the roots removing the fabric.. you will be responsible for watering this summer.. especially if drought.. but after that.. a plant this size should NEVER need water ...

ken

The rocks are fine. I notice the tree above the fence line is doing better. Which direction does it face?

Here are recent pics. I removed most of the fabric since some of the tree is pressing down on it some was hard to remove. 

As you can see from my first pics and now these ones it has less purple flowers.

It gets water twice a week and the tree looks alive very green except I don't know why it ends up having less purple blooms.

Your tree, Vitex agnus-castus, Chaste Tree has a bloom season. It does not bloom all year long. The flowers are fading because it is finished blooming for the year.

@Christopher CNC wow, that's a really short bloom time. I think it had a full bloom for a month if at that. So basically with this type of tree it won't bloom again until next spring?

30 day bloom time is pretty good!

@tootsie yes a month of good bright bloom is good if it maintains the bloom but not good enough if after a month they fade and don't bloom again until next.spring.

There are many trees that only bloom once a year, and to stay bloomed for a month is very good.

Month long bloom is quite good. If you get that, celebrate. That would be considered a pretty good bloom time for most plants, quite good for a tree or shrub.