With temperatures climbing, your pansies are in trouble.
All pansies are descended from the wild English Johnny-jump-up. Tough little plants, they can take extremes of cold, snow--and even hail--but they can't withstand high heat. There's nothing in their genetic makeup that allows them to cope. As a result, they get stressed. Stressed plants are more vulnerable to insects and pansies just become spider mite factories.
My pansies were planted in late February so I've gotten almost four months of pleasure from them. Now it's time to pull them and add them to the compost pile where they'll enrich the garden in a different way.
Replace pansies with flowers from tropical climates. Mexican plants such as zinnias, marigolds and salvias can certainly cope with heat. Gomphrenas are from India; begonias and impatiens are from tropical Asia. The "sunpatiens" are impatiens that can take a sunny position.
Geraniums are native to Africa and are a summer staple. Consider trying the unusual fancy-leaf geraniums that were all the rage during the Victorian era.
Another task to complete very soon is to prune back asters and mums. Cut tall garden asters back by a fourth and aim for a rounded shape. Trim mums by a few inches. Rather than having tall, leggy plants that fall over, you'll get busy asters and mums with loads of flowers this fall.