Perennials: Make sure established perennials are up and growing before crowding in new ones. Think of height, spread, form and color as well as butterfly and hummingbird attractors, when purchasing new tempting varieties. Also plan for late summer and early fall bloom with Japanese anemones, asters and others.
Flowers: If weather has warmed and frost is not forecast, plant zinnias, cosmos, cleome and nasturtiums. Dahlia tubers, salvia, verbena, geraniums and other bedding and container plants can be planted. Keep seed heads picked from ripening bulbs to ensure better blooming next year. Plant gladiolus corms. Set up trellises for summer flowering vines.
Vegetables and fruits: It is full speed ahead on planting: bush beans, pole beans, corn, cucumbers, squash, and melons. Continue sowing lettuce, carrots, beets and broccoli directly in the garden. Established rows of carrots, beets, parsnips, chard and onions should be thinned (three fingers between the little plants). Keep weeding between the rows. Continue hardening off seedlings. Transplant on a mild, cloudy day. If the weather is very hot or very cool, cover new seedlings with a flower pot or hotcap. Seed basil and dill.
Trees and shrubs: Control growth of conifers by cutting back “candles” (new growth) by half. Azaleas are flowering now, and when the flowers fade they can be cut back hard to reshape them.
Lawns: Be aware of the Westchester County regulations on lawn fertilizers: www.westchestergov.com/lawns
Houseplants: Begin acclimatizing houseplants to outdoors. Avoid full sun or windy sites. They may need watering every day. Feed every two weeks with a water-soluble fertilizer at half strength. Some plants, e.g. African violets, are better of left indoors.
— Susan Henry, master gardener with Cornell Cooperative Extension of Westchester