Would you like colour all summer long? Simply use perennial plants with a long-bloom time; they are easy to maintain and will provide colour all season long.
Summer gardening guidelines:
Weed your garden, it's inevitable, they will come
Remove dead flower heads to encourage future blooming
Prevent overcrowding and rot by dividing perennials
Add fertilizer to your soil
Watch for pests and diseases
Water the thirsty plants, the further into summer the thirstier they are
Wear a sun hat, sunscreen, garden gloves, do not overwork yourself and use tools that were made for the task