In a large serving bowl combine the blueberries, peaches, cucumbers, and feta.
In a jar with a lid or measuring cup combine the lemon juice, dijon, honey, olive oil, basil, salt and pepper. Shake or whisk together the vinaigrette until well combined.
Pour the vinaigrette over the salad and gently mix everything together. Taste for seasoning and garnish with extra basil. Serve or cover and refrigerate the salad until ready to serve.