In regards to Japanese Maple and the frost this week, “These trees should recover just fine from frost damage. If the leaves were severely frosted, secondary buds will open up and by mid-summer there should be no lingering effects. If not severely affected, leaves may exhibit some symptoms through the season--nothing to worry about. I’d recommend moderate fertilization and water to help them build vigor this summer, but not too late so they harden off before fall/winter. That being said, these trees are very susceptible to winter injury and Verticillium Wilt, both of which are lethal. So, different trees may be affected by more than just frost.