The turn of the season has arrived, from mid-May to June our weather starts to heat up.
By Memorial weekend it can be almost 100*. Established plants could care less as they are well rooted and toughened by the ups and downs of spring weather. New plantings however will some times freak out due to uneven watering or 'soft' foliage unaccustomed to hotter weather. Be more vigilant and check on these new plantings. It takes most shrubs and trees 36 months to establish themselves.
If your plants have gotten shaggy from the spring flush or have just finished blooming, the next several weeks will be the last best time to prune them. If you wait til July, the hot sun will burn tender undergrowth that is exposed by pruning.
A bit of advice... Prune early in the morning, not only is it cooler, the bees won't be out and if there's a wasp they won't be as active as you run for your life!! I speak from experience.