Black eyed Susan's, daisies, knockout roses and lilies (the orange ones that is) all work in your area and bloom throughout the summer, lilacs and irises add nice color in early summer. Hoped this helped.

I think you should contact with All In One Landscaper.It is a Temecula based Landscaping company.They will definitely solve your problems. Few months ago, I contacted with this company.They redesigned my house at very cheap prices.I was fully satisfied with their commercial landscape maintenance services.

I love hydrangeas. I could see your walkway flanked on both sides with Nikki blue ones.