Skip to Main Content

LuEsther T. Mertz Library
Plant & Research Guides

Library Home Plant Help Research Support All Guides

Library Home Plant Help Research Support All Guides

Spring Gardening Chores: May

Perennial border photo courtesy of Flickr cc/ Mark Levisay
Perennial border photo courtesy of Flickr cc/ Mark Levisay

Chores and Maintenance:

  • Finish preparation of planting beds
  • Continue to cultivate planting beds and carefully remove young weeds
  • Dig and divide early-blooming perennials after flowering
  • Lift, divide and replant late summer and fall-blooming perennials
  • Set supports for floppy plants, vines and vegetables
  • Mow lawns regularly to keep grass at 2 1/2" height
  • Begin watering program as necessary
  • Continue weeding
  • Aerate and moisten compost pile to speed decomposition
  • Mulch azaleas and rhododendrons, and other ericaceous ornamentals with acid mulch
  • Complete edging and mulching of planting beds
  • Deadhead bulbs but allow foliage to remain until yellow to nourish bulbs for next year's display
  • As night temperatures moderate into the 60's, move houseplants outdoors (avoid full sun and windy locations)
  • Look for pests and other problems; spotting early can mean less chemical controls. Note: slugs and caterpillars can be removed manually
  • Begin application of deer repellents

Planting:

  • Move self-sown annuals and perennials to desired locations
  • Sow seeds of corn, cucumber and melon directly in the garden
  • Harden off tomato, eggplant and pepper transplants before planting out at end of month
  • Complete planting deciduous trees and shrubs, weather and soil conditions permitting
  • Continue to plant and transplant perennials
  • Plant summer annuals after last frost date
  • Plant summer-flowering bulbs such as gladiolus and dahlias after last frost date
  • Plant caladium and tuberous begonias in shady spots
  • Complete re-seeding bare lawn areas
Plant summer-flowering bulbs, like dahlias, after the last frost date
Plant summer-flowering bulbs, like this Dahlia 'Ryan C', after the last frost date

Pruning/ Fertilizing:

  • Pinch back late summer and fall-blooming perennials
  • Continue to prune all plant material to remove any diseased, dead, weak or crossing branches
  • Prune early spring-flowering shrubs after blooming
  • Wait to prune evergreens, hedges and other shrubs until late spring into early summer
  • Begin deadheading roses
  • Fertilize roses
  • Fertilize needle evergreens with acid type fertilizer
  • Fertilize bulbs as they finish blooming
  • Fertilize annuals and container plants
  • Fertilize lawns in late May (leaving grass clippings on the lawn can reduce the need to fertilize)

Indoors:

  • Finish re-potting houseplants as needed
  • Take out houseplants as temperatures moderate; move to partially shaded, wind-protected location
Fertilize needle evergreens with acid type fertilizer
Fertilize needle evergreens with acid type fertilizer

*These gardening tips are applicable for an average year in the southeastern New York region: USDA Plant Hardiness Zones 7a and 7b, which include New York City, Northern New Jersey, most of Rockland and Westchester Counties, Southern Connecticut, and parts of Long Island. Plant hardiness zones refer to geographic areas where the growing season of plants is determined by the time of killing frosts in the spring and fall. Even within zones, climatic factors such as altitude, proximity to water, wind exposure, winter sun exposure and snow cover contribute to the existence of different "microclimates" and can influence plant adaptability.

Ask a Plant Expert

Contact Us

with your plant questions by email

plantinfo@nybg.org

Find a Plant at NYBG

Find a Plant at NYBG

Map of NYBG

Noteworthy Books on Garden Maintenance and Seasonal Chores