Spring has arrived and (hopefully) by mid-month we will see our last frost date, although Memorial Day is really the first “safe” weekend to plant tender heat-loving annuals such as tomatoes, peppers and squash. Keep in mind that there is a danger of frost at night until then, so be sure to watch the weather forecast and be prepared with plastic or cloth sheets to cover any tender seedlings you have planted in the garden.
By the (allegedly) last frost date (May 15), you can plant all your annuals. Late light frosts may harm the tenderest annuals such as impatiens, so keep plastic sheets, burlap bags or sheets handy to cover them. Hardy annuals such as geraniums and petunias can tolerate a light frost.
Try some of the new colorful annuals available now. The “Wave” petunias are gorgeous. Some grow to 18 inches tall and are prolific bloomers.
Also look in catalogs and garden centers for natives of New England, such as annual sunflower, Black-eyed Susan, and Cosmos. All can be grown from seed or transplants for that splash of color.
Fertilize spring blooming bulbs early May. Snip the dead flower heads but do not cut back the foliage until it has withered and yellowed.
Cut back the dead top growth of perennials and perennial grasses. Leave about 3 or 4 inches of stems.
Sow seeds for frost tolerant perennials as soon as the soil has thawed, dried, and begun to warm. Some seeds will not germinate until the soil is quite warm, so check directions on the seed pack.
Try some natives in the perennial beds, too, such as baptista (False Indigo), echinacea (coneflower) and the wonderful New England Aster.
When planting new perennials, if the weather has been dry, lightly water the soil the day before you plan on planting. You want it moist, but not soggy. Water the plants in their pots a few hours before planting.
Make holes for new plants wide and shallow. Set the root-ball on undisturbed soil so that your plant doesn’t sink as the soil settles, making it susceptible to crown rot. Don’t mix granular fertilizer into the soil at planting time as it can burn tender young roots. Do use compost. It will never burn the tender plants.
If your tulips are not in the right place, now is a good time to move them. Carefully dig and replant bulbs and their attached foliage in full sun and well-drained soil.
Don’t rush to plant heat-loving plants like tomatoes, peppers, eggplants, and melons. Wait until the soil is warm and the danger of frost is past. Plants exposed to too much cold weather early in their lives may never fully recover. Black plastic mulch laid in the garden bed a several days or weeks before planting will help warm the soil. Also, soil in raised beds warms before that at ground level.
Plant seedlings of cool-weather vegetables early in the month: broccoli, cabbage, kale, mustards, spinach.
Sow seeds of annuals herbs such as dill, chervil, fennel, and cilantro directly in the garden where they are to grow.
Plant green and yellow beans in a sunny location when soil is 60 degrees F or warmer. Water well until germination.
Install upright structures such as teepees, trellises, ladders before planting seeds for climbing veggies such as pole beans, cucumbers, vining squashes, and gourds. Stabilize the structure so it doesn’t blow over in a storm. Plant seeds in soil at the base as directed on the seed packet.
Transplant shrubs and trees after the soil thaws out and dries, while the weather is still cool and before new growth begins.
Apply dormant spray to fruit trees before the buds swell and air temperature will be above freezing for at least 24 hours.
Remove any winter protection wraps from your tree trunks to avoid harboring insects. And remember that winter burn and other winter damage may make the tree or shrub seem dead. Scratch the bark to see if the tissue underneath is green. If it is and the twigs are flexible, just wait, it will green up soon. Do prune off any obviously broken or damaged wood.
Apply a liquid or slow release granular fertilizer to spring blooming shrubs after the flowering is complete and prune them if necessary soon after flowering.
Established azaleas often do not require additional fertilizer. Test soil for nutrient levels and pH. If the soil is low in nutrients, lightly scatter only a few tablespoons of an acid-forming, granular, slow-release fertilizer on soil under the shrub.
Prune dead lilac flowers as soon as possible after they wilt before brown flower heads go to seed. Prune to shape shrub. Next season’s flowers form early in the lilac branches. So late pruning will remove next spring’s flowers.
Forsythia blooms on the previous year’s wood. Just after the golden yellow flowers die, prune to shape the shrub and fertilize.
Water lawns deeply to promote deep roots and develop drought tolerance. The best time to water lawns is early morning. The goal is to apply 1- 3/4 inches of water per week if the weather is dry. However, don’t water unless the lawn seems to need it.
After the first mowing, apply fertilizer. Include pre-emergent for crabgrass if necessary. Crabgrass seed generally germinates after the soil temperature has reached 50 degrees, and requires about 5 consecutive days of 50 degree soil temperature. Again, if the lawn seems heathy, limit fertilizer or skip it. Adding unnecessary fertilizer to the environment is not a good idea. Spread a thin layer of compost to the garden instead.
Set the blades high (3-4 inches) and mow often for the healthiest lawn. Get a mulching kit for your mower and leave the clippings where they land to return nutrients to the soil.