Northern & Central Midwest
Prune Semi-Hardy Shrubs
Cut back butterfly bushes and bluebeard (caryopteris) to about 12 inches, even if the stems survived the winter. This will keep the plants in better shape and blooming nicely. If the stems did die, simply cut them back to live wood or to ground level. Also cut back rosemary to about 4 inches.
Before moving transplants into the garden, they need to be gradually hardened. Expose them to outside conditions for a few days before transplanting. Place the seedlings outdoors a few hours each day, extending the time and exposure as planting time approaches.
Cut Back Ornamental Grasses
Take advantage of warm spells by cutting back ornamental grasses. Cut the dead foliage as close to the crown as you can as early as possible. Leaving old foliage means the plants will start growing much later. Trying to cut out dead leaves after new growth has started will damage the new growth.
Plant Early Crops
Monitor the moisture level in your garden soil. As soon as the soil can be worked, plant small transplants of asparagus, early potatoes, lettuce, radishes, mustard, onions, peas, rhubarb, spinach, turnips, cauliflower, carrots, and all other cool-season crops. Wait until mid-April to plant midseason potatoes.
Support Perennials Early
Get the perennial support systems ready. As perennials begin to emerge, put the support systems in place so you don't damage stems by trying to do it when the plants are large. Whether you use tomato cages, twine and stake systems, or twiggy branches, putting them in place early will help them disappear underneath the foliage.