established flower bed that's too dry
I have a flowerbed along the back of my yard that is approximately 3'x100'. It's bordered in the back by a picket fence and behind that is a large treeline. It receives sun through the morning until about 2 PM. Ideally I would like to have colorful wildflowers and anything to attract butterflies and hummingbirds.
The problem is the trees absorb all of the available moisture, while the rest of the yard can be green this area dries out quickly. Our summers can be brutal, for instance this June even the Black Eyed Susans in the bed dried up. My question is is there anything I can do to the soil to alleviate or at least help the plants? What plants would you suggest I add? How would you water this bed? I currently use a soaker hose but sometimes feel it's a waste.
As you can see by the picture I let it get out of hand this year and the bermuda grass took over (any advice for getting rid of that will be much appreciated as well).