It’s the middle of March, and the garden finally feels as if it’s shaking off its winter coat of grey and brown, with daffodils emerging and blossom unfurling. Spring transforms everything at a pace that can be hard to keep up with. Here are a few suggestions to kick-start the gardening year.
1. Last chance to prune
If you haven’t done so yet, prune any roses. First, make sure your secateurs and loppers are clean and sharp, then remove any dead, damaged or spindly branches and those that are crossing over others, making the cuts just above outward-facing buds — this will encourage a more open habit. The remaining stems of shrub roses can then be reduced in height by a third to a half, and the flowering side shoots of climbing roses cut back by two thirds.
Summer-flowering clematis (those that flower between July and October) should be cut back hard to 30cm above the ground, ideally before new growth appears, but if the stems have started to produce shoots it isn’t a problem.
2. Cut back borders
If you’ve left herbaceous perennials and grasses to stand over winter to provide structure, cut them back to just above the ground to make way for new growth. If the ground is wet, put down wooden boards — old pieces of decking or scaffold planks are perfect — to access the plants, otherwise you’ll trample the soil causing compaction.
3. Divide and move
Now is the best time to divide herbaceous perennials that have outgrown their allotted space, or those that have developed woody centres and need reinvigorating. It’s a great way to get new plants for free to plug gaps elsewhere in your borders.
Dig around the plant and carefully lift from the ground, then use a sharp spade or a pruning saw to slice it in half or into thirds. The most vigorous growth tends to be on the outer edge, so replant this and dispose of the woody centre. Replant and water thoroughly.
Also take this opportunity to move plants if you’re not happy with where they are. It’s easy to think that once a plant is in a certain spot it’s there for good, but that doesn’t have to be the case.
4. Split snowdrops
Fancy a carpet of snowdrops under a tree or hedge? If you already have a couple of clumps but want them to spread quickly, it’s a good idea to split them when the flowers have faded. Simply lift each clump, shake off the excess soil so that you can see the bulbs, tease into smaller clumps of five to ten bulbs and replant them around the garden.
5. Container care
Trees and shrubs growing in containers don’t need to be repotted every spring, but it is a good idea to give them a boost by scraping away the top 5cm of compost and replacing it with fresh. For long-term container growing it’s best to use John Innes No 3.
6. Veg bed prep
Sowing outdoors is worth attempting only once the soil temperature is above 5C, otherwise the seeds will rot rather than germinate. Folklore suggests the soil is warm enough when you can comfortably sit on it with a bare bottom . . . Alternatively you can use a soil thermometer, or a good indication that it’s warm enough is when annual weed seeds start to appear.
Heavy clay soils can take a long time to warm up in spring because they retain so much water over winter, but you can speed things up by covering it. Placing cloches or laying a plastic tarpaulin on areas now where you’d like to sow in a few weeks will help the soil to dry out and raise the temperature.
7. Sowing season
While you’re waiting for the soil to warm up, sow hardy annuals in trays and modules indoors, in a greenhouse if you have one, or on a south-facing windowsill, but hold off half-hardy annuals until the start of April. There’s still time to sow sweet peas if you haven’t got round to doing this yet. Other seeds to sow over the coming weeks include broad beans, chard, spinach, salad leaves, beetroot, cornflowers, nigella, calendula and Californian poppies.
8. Mulch love
Covering the soil in early spring with a mulch of well-rotted compost or composted fine bark will feed the soil, improve its structure, lock in moisture from winter rain and suppress weeds. Don’t mulch if the soil is frozen and make sure the ground is clear of weeds before spreading a layer about 5cm thick on the surface. Leave a small gap around plants, particularly those with woody stems such as trees and shrubs — mulching right up to a plant can cause rot.
9. Weed watch
The key to keeping on top of weeds is to get them while they’re young. Perennials such as dandelions, buttercups and thistles are much easier to remove when their roots are small, and annuals such as hairy bittercress can flower and set seed in just a matter of weeks, colonising an area in no time at all, so swift removal with a trowel or hoe is crucial.
10. Deadhead hydrangeas
If you still have faded flower heads on your hydrangeas you can remove them once you see the new leaf buds start to emerge. Cut Hydrangea serrata, mopheads and lacecaps back to the next pair of buds below the flower. H. paniculata and H. arborescens can be treated the same, or prune each stem back by a third.
11. Plant tonic
Seaweed is a fabulous slow-release fertiliser and soil conditioner, and if it’s harvested with care it is a sustainable resource. Use the powdered form, known as meal, at this time of year, scattered around the base of trees, shrubs and topiary — it can help to keep box blight at bay — and on vegetable beds.