What to Do in the Garden in May

A Regional Gardening Almanac

Bleeding Heart, Dicentra spectabilis
Bleeding Heart, Dicentra spectabilis. Marie Iannotti

Wherever you are gardening, May is sure to be a busy month.Mid-spring is a frantic time in northern hemisphere gardens. As soon as the soil warms, plants suddenly appear out of nowhere and demand attention.

Gardens in warmer climates have already had several months of growing season and the month of May is when you start to transition to extreme heat and a period of respite in the garden.

You may not even need a reminder of what to do in the garden in May, because it is all staring you in the face every time you walk through your garden.

But here are some suggestions of what you might not want to overlook. Don't panic. The season is just beginning.

Everyone

  • Treat yourself to at least 1 great new plant before the best selection at the garden center, is gone.
  • Water regularly, even if rain is predicted.

Flowers

  • Deadhead spring blooming bulbs, but leave their foliage until it turns yellow.
  • Deadhead early spring flowers like pansies and primroses as the blossoms fade and begin replacing them in containers with warm weather bloomers.
  • Give everything a good feeding, to get things growing.
  • Divide crowded perennials and share.
  • Make sure tall perennials are staked.

Vegetable

Houseplants

  • Repot houseplants in new soil.

Trees & Shrubs

  • Check out spring flowering trees and shrubs while they are in bloom and make notes for future purchases.
  • Plant or transplant trees and shrubs before the heat of summer.

Landscape

Pests

  • Keep a watch out for asparagus beetles, aphids, cabbage worms, cutworms, scale, slugs & snails and any signs of fungal diseases (leaf spot, mildew, rust...).
  • Rip out invasive plants while the soil is damp, before they spread even further.

     

Northern Gardens

Vegetables

Flowers

  • Finish seeding annuals.
  • Resist the temptation to put out heat lovers until the end of the month, when night time temps remain above 50 degrees F.
  • Summer bulbs can be planted outdoors.
  • Plant new roses. Prune one-time blooming roses as they faded and feed.
  • Give fall bloomers like asters and mums, a first pinching back.

Trees & Shrubs

  • Plant or transplant trees and shrubs before the heat of summer.
  • Prune forsythia, viburnums and other spring blooming shrubs, before they set next year's buds.
  • Prune spring flowering clematis after blooming to control size and shape.


    Southern Gardens

    Vegetables

    Flowers

    Trees & Shrubs

    • Finish planting new citrus trees and berry bushes for a late harvest.
    • Prune flowering trees and shrubs as they finish blooming.
    • Clean up any drooping or ragged fronds on palm trees.

    Pests

    • Keep a sharp eye out for fungal problems during the rainy season.


    Southern Hemisphere

    • Make sure everything stays well watered.
    • Start putting the garden to bed by cleaning up spent plants and check for over wintering pests and eggs.
    • Continue planting trees and shrubs including conifers and fruit trees and plants.
    • Get spring bulbs planted.
    • Prepare the soil for winter planting. Check soil pH and add organic matter.
    • Consider planting a cover crop.
    • Bring the houseplants back into the house.
    • Start reviewing this year's successes and failures. Keep notes.

    Gardening To Do Lists through the Year:

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