April is such a busy month with longer days and warmer temperatures resulting in bursts of flowers and green leaves everywhere. We are woken up by birdsong and light. Time to get outside and enjoy what Spring has to offer.
Perennials, Shrubs and Trees
● You can still move and plant evergreen trees and shrubs early this month provided the ground isn’t waterlogged. You can also plant container-grown trees and shrubs at this time. Water the plant well in its pot an hour before planting, then set it in a generously sized square hole so that the top of the compost is level with the ground around it. Mulching around newly planted trees and shrubs will help to lock in moisture, provide nutrients and give them a good start in their new home.
● Check tree ties on existing trees and loosen if required. It is important to not stress the tree, damage the bark or restrict sap flow.
● Continue planting new perennials and aim to get them into the ground by the end of the month so that they have sufficient time to establish while the weather is mild and wet. You should also finish dividing and replanting summer-flowering perennials.
● If your winter-stemmed shrubs such as Cornus and Salix that are grown for their colourful foliage have not yet burst into leaf, you might just be able to prune them. The best time to prune is late winter/early spring while they are still dormant and developing buds. If in leaf, best to wait until next year!
● Prune early-flowering shrubs (Pruning Group 2), including Forsythia and Chaenomeles (ornamental quince) only once the flowers have died back. Cut back the flowered branchlets to vigorous young growth lower on the main stem and remove 20-25% of old growth to the base. Next year’s flowers will form on this summer’s woody growth.
● As temperatures rise, you can safely prune more vulnerable shrubs and perennials such as hydrangeas, penstemons, lavender, helichyrsums, pennisetums, etc. Be sure to cut just above a healthy bud.
Photo: Hydrangea 'Limelight' pruned back to its framework structure. New leaves emerging.
● April is a good time to start checking your box plants for box caterpillars and moths, particularly if temperatures are mild. Early prevention is key and you can easily remove box caterpillars by hand if only a small infestation. We would recommend spraying your box with Xentari, a natural biological insecticide from early April and repeat every six weeks until September.
● Tie in climbing and rambling roses as the new shoots emerge, training them to grow as horizontally as possible to encourage a greater number of side shoots. Shoots of climbers, such as Clematis, should also be tied in.
● Plant out all summer-flowering bulbs by the end of the month.
● And now is not a bad time to start thinking about supports for your taller perennials or ones that are more prone to flopping. Hazel stems make great supports as they are very flexible and can be bent and twisted together to provide strong supports.
Photo: metal cage for peony.
Kitchen Garden
● Make sure you have planted all your seed potatoes now. Plant spacing depends on the variety (e.g. early, salad, main). Remember to earth up row once you see shoots emerging.
● Finish planting out onions, shallots and garlic if you haven’t done so already.
● Direct sow spinach, chard, kohlrabi, beetroot and fennel.
● Keep up successional sowings of lettuce, radish, beetroot, peas, broad beans, spring onions and turnips. Sowing little and often will help to avoid a glut of produce at the same time.
● Sow French beans, runner beans, squash, sweetcorn and courgettes under cover now for planting out once danger of frost has passed.
● Mulch fruit trees, soft fruit bushes and canes now. They will all benefit from mulch as well as feed such as chicken manure pellets. Keep weeds under control around cane fruits and your strawberry plants as they can act as hosts to pests and diseases.
Cutting Garden
● Plant out your sweet peas! I typically plant one to each upright to avoid congestion and give them room (but Sarah Raven does suggest two to each upright). Be sure to tie in at the base and encourage it to wind around your support.
● Pot up dahlia tubers that have been stored or that you have recently purchased to encourage strong shoots before planting in final place.
● Continue to prick out seedlings sown earlier in the year. Harden off any that will be ready for planting towards the end of the month.
● There is still time to sow hardy annuals such as marigolds, poppies, nigella, cosmos, Cerinthe, if you didn’t manage to last month.
Other Jobs
● Keep an eye on the weather forecast; cold snaps are still likely so keep cloches or fleece handy for tender plants on frosty nights.
● Be aware that the spring rain and milder temperatures will see a rapid increase in slug and snail populations. There are several organic ways they can be controlled, including nematodes and beer traps. It’s also worth encouraging hedgehogs, frogs, toads and thrushes into your garden, as they will consider those slugs and snails a tasty treat.
● Aphid populations also start to increase at this time of year. Rub or hose them off infected plants to prevent colonies building up.
● By now your lawn probably needs to be cut fairly regularly. Blades should be at their highest setting when you first start mowing and can gradually be lowered each time you mow.
● Sow new lawns on prepared ground. Grass seed should be scattered evenly over a fine tilth, raked in lightly to improve seed to soil contact and then watered with a fine spray or sprinkler.