By Trish Hoff
April is one of the busiest months in the garden but take some time to enjoy the warming weather and enjoy the blossoms. Look for cherries, spring flowering shrubs – rhododendrons, daphnes, viburnums, star magnolias, clematis – and a vast array of spring flowering bulbs and early perennials.
Seeds:
Sow half hardy and tender annuals indoors 6 – 8 weeks before your last frost date to get an early start on the season. Thin or transplant seedlings started earlier. Begin hardening off vegetable and annual flower seedlings by moving them into cold frames or outside on warm days and back inside for the night towards the end of the month (as the weather warms up to 10C during the night and 18C during the day when it is safe to leave them outside). Don’t leave them in hot, direct sunshine until they are fully hardened off.
Vegetables, Fruits and Herbs:
Clear your planting beds of any weeds that have germinated. Add 4 to 5 cm of compost if you have not already done so. If the soil is not compacted, there is no need to dig it in, worms will do the work for you.
If the soil is too cold, cover with black plastic sheets for a couple of weeks to warm up the soil.
Plant cool weather root crops, peas, brassicas (broccoli, cauliflower…) lettuce, spinach, onions directly into the garden or sow indoors under grow lights.
Bulbs, tubers and Corms:
Fertilize your spring bulb as the flowers fade.
Deadhead the spent flowers but leave the foliage to mature and feed the bulb for next year. Only remove or mow the foliage after it has turned yellow or brown.
Take pictures of your bulbs in bloom so you will have a reference of what and where to add new bulbs in the fall.
Remove tender bulbs and tubers from storage. Pot up summer and fall flowering dahlias, gladiolas, cannas or alocasias/colocasias. Start them growing and use later for container displays or spots in the borders. Add any necessary stakes and labels at planting time.
Perennials:
Divide and move any perennials as needed. Weed and mulch the beds.
Begin moving over-wintered tender perennials outdoors as weather temperatures permit.
Stake tall or heavy perennials such as peonies and delphiniums now before they get too large. Staking when they are larger makes the plant look awkward and stems can easily break. Use twiggy branches, stakes, wire or plastic mesh cages that will disappear into the foliage as the plant grows.
Shrubs and Trees:
Prune early flowering shrubs as soon as they finish blooming, many of these set next year’s flowers on the newly emerging wood. Pruning them later may remove next year’s flowers.
Add mulches (compost under trees and shrubs but do not cover the crowns or trunks.)
Feed rhododendrons, azaleas and camellias before and after flowering.
Fertilize roses.
Clip hedges to maintain their size and shape before the birds start nesting. Shear winter flowering heathers.
Lawns:
Begin cutting lawns that do not have spring flowers or bulbs growing in them. Use a sharp lawnmower blade. Rake and overseed bare spots.
Pest Patrol:
Keep ahead of weeds in the vegetable and flower beds. They are stealing your plants’ food!
Patrol for slugs and snails, particularly around newly emerging perennial growth tips.
Check for aphids on the new growth of roses.
Watch for cut worms and insect larvae in the planted beds.
Indoor Plants:
As indoor tropical plants start to put out new growth, tidy up and feed the plants with half strength fertilizer. It is a good time, now, to divide and pot-on overgrown plants.