Prune These-

• Summer flowering shrubs such as Anthony Waterer spirea and potentilla may be cut back to 6in off the ground. These plants bloom on new wood and will quickly grow back and bloom in mid-summer.
• Neglected overgrown shrubs (even spring blooming) can be pruned heavily this time of year. You might lose their blossoms for the next 2-3 years, but hopefully, you will rejuvenate the health of the shrub.
• Shrubs grown for their foliage like alpine currant, barberry, burning bush, dogwood, honeysuckle, ninebark, purpleleaf sand cherry, smokebush, and sumac should be pruned before growth begins.
• Smooth hydrangeas like Annabelle, can be cut back to knee-high. They bloom on new wood, so you will still get great blooms.
• Pee Gee (panicle) Hydrangeas have woody stems. Some examples are Vanilla Strawberry, White Diamond, Bobo, and Diamond Rough. These bloom on new growth so you can trim off old blooms and shape them this time of year.
• Most fruit trees should be pruned in the early spring before the buds have set. If your fruit tree has buds, you can still prune your tree but you will lose fruit for the coming season.
• Vines like grapes, wisteria, and trumpet can be pruned to the desired shape. There are many types of clematis and they require different pruning. 
• Evergreens like yews, arborvitaes, and junipers can be pruned in early spring to late summer.

• Spring-blooming trees and shrubs like lilac, forsythia, azalea, rhododendron, apricot, chokeberry, chokecherry, flowering plum, flowering cherry, and magnolia. Their buds are already set and you’ll lose their blooms for the year.
• Bigleaf hydrangeas like Endless Summer and Summer Crush, bloom on old wood and set their blooms in late summer to early fall. If you trim them in the fall or spring, be selective only taking dead or weak branches and leaving plenty of buds for blooms later on. 

• Start vegetable seeds indoors using a sterile soil mix that is kept uniformly moist. Provide good light and transplant seedlings into 4” pots when they are about 1” tall. Keep the plants indoors in a warm, bright place until they are transplanted outdoors in late May.

Here’s a great article from the University of Minnesota, that gives more details: Vegetable Garden Prep