May 15th is the last frost date for Zone 4. After the first day of Spring, many of us are chomping at the bit to get out in the garden and begin spring planting. A little caution is called for since the weather can be unpredictable and a late freeze or snowstorm can undo a lot of hard work. Prepare to protect seedlings in the garden from frost by preparing cages and stakes that you can cover with cloth on cold nights. Click on the map at right to find your zone.
Plant lilies, primroses, and lilies-of-the-valley. Cut back ornamental grasses to three or four inches when you can see new growth at the bottom.
Fertilize spring blooming bulbs in April or early May.
Now is the time to dig and divide mature perennials that are bare in the center, no longer bloom well, or are taking up too much territory, as well as those you wish to propagate. Divide when the new growth is 4-6 inches tall.
Clean out your perennial beds by hand to avoid damaging emerging shoots. Then apply a balanced, organic fertilizer over the old mulch and top dress with fresh mulch.
Apply a trowel-full of wood ashes and one of manure or compost to your peonies – more if you have large plants. If your peony never blooms, it is either planted too deep or in a too-shady location.
Plant cool season annuals like pansies as soon as the ground has thawed and dried.
When the soil has warmed and dried, plant cold-tolerant crops, such as peas, spinach, lettuce, radishes, and onion.
Start broccoli seeds indoors for an early crop.
Start tomato seeds if you plan to set them out under protective covering next month.
Fast growing, cold tolerant arugula is one of the earliest greens ready for harvest. Sow seeds in the garden as soon as the soil can be worked and begin picking tender, 2-3 inch baby leaves in about a month.
Sow seeds of cool weather-loving sweet peas directly in the garden six weeks before the last frost date. Soak the seeds overnight prior to planting.
If you started your peas indoors, well hardened-off seedlings are tolerant of light frost and can go in the ground a couple of weeks before the last frost date. When plants are 6-8 inches tall, pinch them to encourage denser growth. Be sure to give sweet pea vines a support to climb.
Plant raspberries as soon as possible, but wait until the soil has begun to warm before planting strawberries.
Spray apple, peach, and pear trees that have canker problems.
Apply dormant oil to shrubs and trees early in the month to kill most insect eggs. Make sure you do this while plants are dormant and air temperatures will be above freezing for at least 24 hours.
Move shrubs and trees and plant bare-root trees, shrubs and roses after the soil thaws out and dries up, before new growth begins.
High winds, heavy snow and freezing rain can damage our gardens and yards in the winter, so spring is the time to inspect for damage, prune back or remove broken stems and branches, clean up any debris and remove any plants that just didn’t survive.
Every few years, potted trees and shrubs should be re-potted and root pruned. Top dress each year before growth begins.
The cardinal rule is to prune shrubs after they bloom, but for late-blooming clematis and hydrangeas, various shrubs and fruit-bearing woody plants, early spring is the time to prune them into shape.
Test the soil in your lawn and add lime or other additives before the growing season starts.
Now is a good time to fluff the lawn with a broom rake. As lawns mat down over the winter, a lack of air circulation around the grass plants can lead to mold diseases. The bright sunshine has a powerful sterilizing effect, and fluffing the grass will add air and help prevent fungal lawn diseases.
Avoid the urge to apply fast-release lawn food to your lawn. Pushing the grass to be the greenest will predispose your lawn to leaf spot diseases. Additionally, the lawn will need to be watered earlier, mowed sooner and more often.
Garden image: Wiki Commons/southernfoodwaysalliance