Starting May 1, pinch back late-summer and fall-blooming perennials, such as chrysanthemums and asters, about every two weeks until the middle of July. This keeps them stocky and full.
Pinch First-Year Strawberry Blossoms
Remove flowers of newly planted June-bearing strawberries as soon as they appear to allow the plants to put strength into developing roots. Remove flowers of everbearing and day-neutral strawberries until July 1. After that, allow them to flower and enjoy the fall crop.
Plant Warm Season Crops
Once the danger of frost is past and the soil is warm, it's time to plant warm-season crops such as peppers, eggplants, and tomatoes. Also, houseplants that will spend the summer outdoors can be taken outside then. Be sure to gradually acclimate or harden off any houseplants and seedlings raised indoors (this includes ones you purchase from a greenhouse) to outdoor conditions of temperature, sun, and wind before setting them outside for good.
Take Care of Your Peonies
Peonies will be getting ready to bloom soon. Fertilize them with a general garden fertilizer, and make sure you have support for the large blossoms so they don't droop after a rain. To produce larger blossoms, pinch off the smaller secondary flower buds as they form.
Nip Rose Problems in the Bud
Fertilize roses after their first flush of flowers. Deadhead hybrid tea roses as soon as the flowers fade, and constantly monitor the leaves for black spot. Remove any infected leaves and begin spraying with the Cornell baking soda formula (1 tablespoon horticultural oil plus 1 teaspoon liquid soap in a gallon of water).
Monitor Container Plants for Moisture
As the weather warms, be sure to monitor containers and hanging baskets daily. Remember that clay pots dry out more quickly than plastic. If the soil dries out enough to pull away from the sides of the pot, immerse the entire pot in a bucket of tepid water for half an hour and then let drain.
Watch for Aphids
Keep careful watch for pests such as aphids the season progresses. The days are warming and lengthening and aphid populations will be growing to begin feeding on new growth. Control aphids by dislodging them from plants with a spray of water from a hose. You can also control them by spraying insecticidal soap.
Harden Warm-Season Transplants
Begin hardening off warm-season transplants, such as tomatoes, eggplants, and peppers, for transplanting into the garden in a few weeks. Move them into a cold frame or protected area and gradually expose them to wind and sun over a week or two. By the time the weather is warm enough, they should be tough enough to put in the garden with no setback.
Once the danger of frost is past, move overwintered houseplants into a partly sunny location outdoors. Harden plants off first by putting them outdoors for a few hours each day for a week before leaving them outdoors for summer. Keep plants well watered and fertilized.
Thin Fruit Trees
Check fruit trees for crowded or badly placed shoots and rub off buds and small shoots that are growing in the wrong direction. For fruit trees that produce clusters of fruit, such as Asian pears, peaches, and apples, pinch out all but one per cluster to put energy into ripening the remaining fruit.
Mow Lawns Frequently
Lawns are growing fast. Remember to mow grass frequently so you're not cutting more than one-third of the grass height off at any time. Keep lawns well watered if the weather has been dry. Wait until fall in southern areas to fertilize.
Plant cucumbers as soon as the last frost date has passed and the soil has warmed somewhat. Plant vining cucumbers next to a sturdy trellising system. You may need to assist the plants in attaching to the bottom of the trellis, but once attached, they will climb easily by themselves.
Plant Green Beans
Plant green beans. Also called snap beans, they come in pole and bush varieties. As soon as the last frost has come and gone and the soil has warmed, sow your first seeds. With bush varieties, sow every two to four weeks for a harvest of tasty snap beans all summer.
Save on Potting Soil
If using large containers, it is expensive to fill the entire pot with soil. For annuals, you only need eight to ten inches of root room, so fill the pot with inverted plastic pots or a plastic bag filled with Styrofoam peanuts to take up the extra room. Make sure your container has drainage holes. Don't be tempted to put stones in the bottom for drainage - it doesn't work.
Assess Bulb Plantings
Assess your spring bulbs as soon as they finish blooming. If they didn't bloom well, they may need to be llifted and divided. If they Most hybrid tulips fade out after a few years and are best replaced regularly. For a longer term show, consider investing in botanical or species tulips that will thrive for years. Don't trim off tulip foliage until it begins to yellow.
Bring in Butterflies
Bring beautiful butterflies to your garden with nectar-producers such as coneflowers, Russian sage, Joe-Pye weed, butterfly weed, bee balm, catmint and zinnias. Also provide plants for larvae to munch on, and don't waste your money on butterfly houses, which they won't use. Avoid using any pesticides.