Trish Hoff
The May Marathon
Keep weeds at bay – hoe regularly. Choose a dry, sunny day and the uprooted seedlings will shrivel up. Remove established perennial weeds with a fork – get all the roots. Then mulch bare areas to discourage new seedlings. Add mulches to the soil under trees and shrubs (but not touching the trunks) to help conserve moisture and reduce weeds.
Monitor plants for signs of disease and watch that beneficial insects are keeping insect infestations under control. Remove slugs and snails feeding on newly emerging shoots. Check for aphids on roses’ new growth.
Bulbs
Fertilize bulb plantings and allow bulb foliage to die back naturally. Mark any holes in bulb plantings with plastic garden markers (make your own from plastic yogurt tubs or plastic forks) to guide fall bulb planting.
Plant summer flowering bulbs and tubers.
Perennials
Plant new perennials anytime in May. Divide and move plants as they emerge from the ground. For late transplanting wait for a cool, shady day and water thoroughly. Add lots of compost and well-rotted manure to planting holes.
Tidy up spring flowering perennials and feed them to improve their size and quality for next year.
Stake tall perennials now before they mature. Use hoops or twiggy branches to support potentially floppy plants and wooden stakes for tall or fragile plants such as delphiniums or dahlias.
Annuals
Sow hardy annuals directly into the garden.
Harden off tender annuals before planting them outside. Place them in a shady spot gradually exposing them to more sun each day. Cover them at night so they gradually adapt to cooler temperatures.
Pinch out the growing tips of annuals, asters, cosmos, zinnias and mums to promote bushy growth.
Plant containers and hanging baskets. Consider using potting soil with water-retaining gel crystals to reduce watering requirements. Use larger pots that hold moisture longer and arrange containers in groupings to reduce watering frequency and labour.
Set up or test any drip irrigation systems to ensure that they are working properly.
Vegetables
Save your back and consider the “No Dig” method of planting. Spread mulches, composts, manures, and other additives over the surface of your planting area, just as Mother Nature does and leave it to the earthworms and other soil residents to pull the nutrients and amendments down into the soil to improve its tilth.
Plant cool-season vegetables such as radishes, peas, onions and carrots, early in the month and warm-season vegetables after the risk of frost has passed at the end of May or early June. To start earlier in the month, use row covers and cold frames.
Plant broccoli in mid-May but leave cauliflower until night temperatures are warmer at month’s end. Mix sand into the garden soil where you sow carrot seeds.
Avoid transplant shock – water seedlings well and plant on an overcast day.
Try pots of herbs near the kitchen for both ornament and quick access for cooking.
Lawns
Mow often, adjusting the mowing blade as the temperatures warm up. Or adopt “No Mow May” to encouraged grasses and wildflowers to help feed pollinators.
Fertilize with a slow-release fertilizer.
Prune early flowering shrubs such as forsythia, rhododendrons and spirea after flowering. Trim evergreens, hedges and topiary specimens. Check for nesting birds first.
Plant trees and shrubs as early as possible – preferably before they leaf out. Make sure to check the mature size of new trees and shrubs and give them lots of room to grow.
Dig a planting hole three times wider than deep and only as deep as the root ball. Back fill the planting hole with native soil. Too rich soil will discourage roots from growing out of the enriched area and cause circling of the roots. Loosely stake the plants in areas that are windy. Do not restrict the movement of the plant too much. Research has shown that plants that can move slightly with the wind develop stronger roots and trunks.
Water new woody plants every week for the first growing season (depending on local rainfall).