SeasonTips & Tricks

May Gardening Tips

Sunny Gardens | May Gardening Tips

May Tips

Sunny Gardens | May Gardening Tips
Sunny Gardens | May Gardening Tips

Plant seed or seedlings of warm-season crops like:

  • tomatoes
  • peas
  • beans
  • sweet corn
  • cucumbers
  • eggplants
  • melons
  • peppers
  • pumpkins
  • and summer squash.

Sow beets, carrots, lettuce, and radishes.

Plant herbs such as:

  • thyme
  • sage
  • parsley
  • chives
  • basil.

Plant spring flowering shrubs like:

  • rhododendrons
  • azaleas
  • camellias.

Plant or sow summer annuals such as:

  • geraniums
  • marigolds
  • lobelia
  • impatiens
  • sunflowers
  • zinnias
  • cosmos
  • alyssum
  • phlox.

Transplants become less stressed when they are set out on a cloudy, calm day. Unfortunately, gardeners may need to transplant when they have the time, regardless of the weather. Strong sun and wind are hard on new transplants, so set out plants in the late afternoon when the wind comes down and the plants have overnight to acclimate. Provide shade and wind protection with berry baskets, small crates, or screens. Mulching helps since it lowers the rate at which water evaporates from the soil and controls the soil temperature.


Feed roses after their first bloom, then repeat feeding every four to six weeks. Try a complete fertilizer like a 10-10-10 granular or liquid soluble Fertilize everything right now. Annuals, fruit trees, fuchsias, perennials, shrubs, etc. Use a higher phosphorous fertilizer like a 10-60-10 for better flower, fruit, and vegetable set.

Feed spring-flowering shrubs like azaleas, camellias, and rhododendrons with an acid-based fertilizer as soon as they have finished flowering. Later in the month, thin fruit on heavily bearing trees. With triples and doubles, prune to singles.

Sunny Gardens | May Gardening Tips
Sunny Gardens | May Gardening Tips

To revitalize and encourage branching remove spent flowers from camellias, roses, azaleas, fuchsias, geraniums, rhododendrons, impatiens, and all annuals. This will lengthen the flowering time for each plant and keep it shaped and compact. Newly planted trees and shrubs should be watered deeply every week or two until fall rains begin. Water established trees and shrubs deeply and infrequently to help withstand summer heat. Mulch soil to save water, smother weeds, keep the soil cooler. Spread 1-3 inches (2.5-7cm) of bark chips, compost, wood shavings, or other organic material under shrubs trees, annuals and vegetables.

Prune spring-flowering shrubs and vines after bloom. Prune rhododendrons immediately after flowering. Old clusters should be snapped off when partly dry, but remove with care in order not to decrease or prevent bloom next year. Divide indoor plants when new growth starts in spring. Root cuttings during spring and summer when the plant is actively growing.

Letting a young lawn grow too tall and then cutting it back to the recommended height is detrimental. Such extreme leaf removal stops the flow of food to the roots, weakens the plants, and opens the lawn to diseases. Never let it grow so tall that you have to cut off more than one-third of the grass blade.

To keep garden plants growing at a steady rate, fertilize them with manure tea or diluted fish emulsion every six weeks. Lightly side dress perennials, including spring bulbs, with a 5-10-10 or 10-10-10 fertilizer, being careful to avoid the centre or crown of the plant.

Caladiums need generous amounts of water and fertilizer to encourage continuous production of new leaves during the summer. Apply a light, side dressing of 5-10-5 fertilizer every two weeks, and water thoroughly to encourage bright-coloured foliage.

Pinch back annuals when 4 to 6 inches (10 to 15 cm) high to promote bushy growth. Some that require pinching are zinnias, petunias, and salvia.

Weed and Pest Control

Keep an eye out for aphids and earwigs and get them before they take over your plants. Where earwigs and sowbugs (slaters) are a problem, try trapping them with rolled up newspapers moistened with water. The insects will hide in the papers by day. Gather up the traps and dispose of them frequently. Continue weeding, either by hand, hoeing or by using a pre-emergent. All those jobs can be done by Sunny Gardens, just contact us for details of garden maintenance, landscaping and design.


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