With May comes the certainty that the gardening season is truly upon us. Most of North America reaches their frost-free date this month, which means it's time to plant out all of those heat-loving vegetables and annuals. Along with all of this growth comes the need for vigilance against pest and disease problems. This month's tasks will keep your garden in excellent shape.
This list is broken down into short season regions, mid-length season regions, and long season regions for the sake of simplicity. Here is how the regions are determined:
- Short Season: USDA Hardiness Zones 1-4
- Mid-Length Season: USDA Hardiness Zones 5-7
- Long Season: USDA Hardiness Zones 8-11
Short Season Tasks
- Fertilize bulbs with bone meal after they have finished blooming.
- Fertilize spring-blooming shrubs with composted manure or fish emulsion.
- Prune forsythias, lilacs, and other spring bloomers that bloom on old wood as soon as they are finished blooming.
- Check the lawn for signs of grubs. Apply milky spore if you discover more than ten grubs in one square foot of lawn area.
- Watch young transplants for signs of caterpillar damage. Pick off and destroy any caterpillars you see.
Mid-Length Season Tasks
- Protect summer vegetables, such as tomatoes, cucumbers, and peppers, with floating row covers to protect them from late season frosts.
- Begin feeding roses every two weeks with a high-phosphorus organic fertilizer to encourage plentiful blooming.
- Plant tubers for dahlias, cannas, and caladiums, and fertilize with bone meal.
- Use insecticidal soap to protect emerging dahlias from mites.
- Install cutworm collars around vegetable transplants.
- Inspect cucumbers and melons for signs of the cucumber beetle.
- Install stakes or other supports for tall plants such as delphiniums, hollyhocks, and peonies.
- If you haven't already, apply mulch beneath fruit trees to prevent against insect pests such as apple maggots.
Long Season Tasks
- Be vigilant about pests in the vegetable garden: inspect plants regularly for aphids, bean beetles, potato beetles, and squash bugs. Remove and destroy them as you find them.
- Set up bird netting on fruit and berry trees and bushes.
- Thin fruits on fruit trees.
- Mulch ornamental trees and shrubs, as well as perennials and annuals, to protect them against heat and drought.

