Ask Mr. Smarty Plants

Municipalities always reserve "right-of-way" on property on which they can place sidewalks, fill dirt, utility lines, whatever, without the permission of the owner. The addition of dirt must have had to do with leveling the grade after the sidewalk went in, and the grass is part of the project. Of course, any new planting needs to be watered, especially if it has been planted in the blazing Texas Summer, which we don't recommend.

According to this USDA Plant Profile map, Sapindus saponaria var. drummondii (western soapberry) grows natively in the area of Tarrant County, so it is planted appropriately. The good news ends there. Think about the part of the plant you can't see, which is the roots. Most woody plants will have roots in proportion to their height and width. Roots are vital for intake of moisture and oxygen to send up to the leaves to provide food to keep the tree going. Your tree roots are now covered by impermeable concrete and a layer of soil that is thick enough to be impermeable as far as your roots are concerned. The soapberry is a low water use tree, although its native habitat is  stream banks; wood margins; and rocky hillsides. That daily water spraying is good for the grass but bad in terms of water probably hitting the tree trunks, where it can cause fungal problems. Our uneducated guess is that the soapberry trees are not going to survive the invasion.

Can they be moved? Hopefully, you won't even try it now, at the first of a still-hot September. Woody plants should be planted or transplanted in late Fall or early Winter, when they are in dormancy. From our Native Plant Database page on this plant:

"Soapberry often suckers and form groves. Tolerant of drought, wind, heat, poor soil, air pollution and other city conditions."

What you have may not be "a" tree, but a suckering grove of trees.  To transplant, you will have to separate suckers from the main roots, hopefully with enough roots on each sucker to sustain the tree. A long, relatively narrow shovel with a sharp cutting edge. sometimes appropriately called a "sharpshooter," could be used to dig out those suckers, retaining roots directly from the sucker but cutting through the main root from the parent tree. Difficult, and no guarantee of survival.

Because the fruit of the soapberry is known to be poisonous, it is recommended that it be planted away from where childen would regularly contact the fruit, like a sidewalk.

It appears to us you have a "Catch 22" situation. The trees are probably not going to survive in the position where they are now, it is the wrong time of year to transplant, and transplanting would be difficult, plus they are a potential threat to passers-by, both from the possibility of slipping on the berries on the sidewalk and from the poisonous alkaloid saponins in the berries. To add to your decision, the dead plants (if they die) will have to be removed anyway. If you have a place and are willing to make the effort to relocate the trees, you might as well try it. 

From our Native Plant Database:

Sapindus saponaria var. drummondii

Sapindus saponaria var. drummondii

Sapindus saponaria var. drummondii

Sapindus saponaria var. drummondii