Gardening Notes

April

• Lift and divide polyanthus after flowering.
• Cultivate spring flowering alpines for the rock garden.
• Cut back tender perennials.
• Divide asters.
• Plant evergreen trees and shrubs.
• Sow hardy annuals in situ.
• Sow vegetable seeds.
• Prune less hardy shrubs like Ceanothus, Fuschia and Hydrangea.
• Mulch beds to help eliminate weeds and conserve moisture.
• Plant water lilies. 
• Lift, divide and replant overgrown clumps of marginal pond plants.
• Give the terrace a spring clean to remove dirt, moss and weeds.
• Hoe borders to keep on top of emerging weed seedlings.
• Now’s the time to patch-repair worn spots in lawns. Sow seed, buy a little turf, or swap a bit of turf from somewhere else less conspicuous. Some granular fertiliser under the turf will get it off to a strong start.
• Look over evergreens – hollies, cypress, juniper, yew, laurel – and cut out wayward, sprained or misplaced branches. Cut back to a live shoot.
• Patio pots of lilies need to be in full light, but somewhere safe from late frosts and not in baking sun where they will race up to flower too soon.
• On warm days, open your greenhouse and conservatory ventilators, but close them again at night.
• Make sure the blades of lawnmowers are sharp, rotary mowers included. Blunt blades rip the grass and leave rough ends, which turn brown and stop the lawn looking quite so verdant. A file will sharpen a rotary mower, but do keep the blades evenly balanced or the machine will run unevenly.
• As the grass begins to grow ever more strongly, lower the blades of the mower to your desired summer height. A light feed helps the grass get the better of mosses.
• Lawns flush with paving gradually creep over the surface of the paving. Cut back the turf with a half-moon cutter, especially around stepping stones, so as not to lose hard space.
• Remove any green shoots appearing on variegated shrubs.
• Lift, divide and replant overgrown clumps of primroses and polyanthus.
• Protect greenhouse plants from the sun by applying shading paint to the glass.
• With a bit of luck we are through with frosts for the year, so it’s worth putting out hanging baskets and containers. Don’t do it on a windy, sunny day; let your plants acclimatise to the outdoors by giving them a still, grey day or two first.
• Make sure you leave enough space in the container above the compost for generous watering, and in baskets use proprietary basket compost (which has water-retaining properties) to make watering effective and efficient in summer heat. Meanwhile, be mean with the water until the young plants have put out new roots and are definitely growing and thirsty.
• Resist the temptation to tuck new shoots on wisteria, ivy and honeysuckle behind convenient drainpipes; in the long term the expanding stems will push the pipes off the wall and have to be cut back. Take the trouble to tie the shoots to wires.