Spring clean: It's time to grab those secateurs and start the vital job of pruning

TOP JOB FOR THE MONTH

The first thing to do in March is to find your secateurs and give them a quick blast of oil. They've a lot of work ahead – pruning and cutting back come top of the list of jobs to do this month. The shrubs that need pruning now are those that bloom in the second half of the summer, or the ones that have been going all through the winter, such as yellow-flowered jasmine.

By nature, jasmine has a languorous, drooping habit, but the savage haircut it's often given after it has finished flowering reduces it to a stubby thicket. You are left with too much of the old wood (pale brown) and not enough of the new (bright green), which will bear next year's flowers.

Instead of shearing it all over, tackle the jasmine section by section, taking out some of the old stems entirely and tying in the new growths that shoot from the base of the plant. Think of the jasmine as an up-and-over shrub. The ups are the old, pale-brown branches that you cut out in rotation. These need to be pinned securely to their support. The overs are the bright green growths that come from them and which can fall freely in front of them.

Buddleia is another shrub that needs plenty of new growth to produce the best display of flowers. Encourage that by cutting out all weak and straggly growths entirely. Then cut back the rest of the stems drastically, leaving just one or two pairs of buds on each branch.

Climbing roses need attention, too (ramblers should have been dealt with last summer). The climbers I'm talking about are the ones that look like hybrid tea roses on stilts. Roses in this group flower on new wood but (unlike ramblers) rarely produce it from the base of the plant. You are much more likely to find new shoots growing from old wood higher up the plant. Cut old stems back to the junction with the new growth and tie the new growth in. Cut back side branches springing from the main ones to about 15cm/6in.

Now and again, it pays to take out a stem completely at ground level, especially when the main framework has crept higher and higher up its support. This drastic reduction sometimes forces the rose to send out a new shoot from the base. A hefty spring mulch will help, too.

All dogwoods, such as Cornus alba 'Elegantissima', grown for their decorative winter bark, should be cut back hard now. The bark colour is much brighter on new growth than old, so you want as much of it as you can get. I work on a rotation, cutting a third of the stems down each season. That is because I do not want to lose the shrub entirely for a period each year.

Late-flowering clematis should be cut down now, just above a likely pair of buds, leaving about 45cm/18in of stem. By 'late', I mean the types such as 'Jackmanii Superba' which start flowering in July. All the Viticella clematis such as 'Abundance', 'Étoile Violette', 'Royal Velours' and my favourite, 'Venosa Violacea' need cutting back hard now.

FIND TIME TO TIDY UP

This does not have the same drama as pruning, but the cumulative effect is as important. Cut old, battered leaves away from clumps of Lenten hellebores, now in full bloom. Work your way through clumps of carex, Bowles's golden sedge, cutting out the wizened, dried fronds. Cut back battered fern fronds so that the new ones can unfurl later in spring.

Take the old dried flower heads off climbing hydrangeas and do the same for big shrubby hydrangeas such as H. sargentiana and H. villosa. Cut back dead stems of catmint before they become entangled with the new growth. Cut back clumps of Michaelmas daisies that you forgot to attend to last autumn.

SOW VEGETABLES

If the soil is not wet and cold, first sowings of vegetables, such as broad beans, can be made outside. If you have a cold frame or greenhouse, start off beetroots and parsnips inside by sowing seed in a length of gutter, filled with compost. When the seedlings are well established, transfer them outside. Press a spare length of gutter into the ground to make a shallow depression. Then carefully slide the contents of the planted gutter into their new home.

Start off seed of tender vegetables such as aubergine, peppers and tomatoes inside. When the seedlings are well established, you can transplant each one into its own pot. They'll need to be kept under cover until May.

Think seriously about potatoes. Although you do not need to plant them until April, you have to lay hands on seed potatoes well before that and set them sprouting in some light, airy, frost-free place. Line them up in egg boxes or wooden apple crates.

First earlies will produce a crop of roughly 25kg (a sackful) from 3kg of seed potatoes, main crops roughly 35kg from the same amount of seed. I have a weakness for the old varieties, such as 'Catriona' and 'Dunbar Standard', a maincrop potato with long oval tubers and white flesh. You can boil it, roast it, turn it into chips. This is a very late potato, often not ready until October.

'Epicure' is an even older variety, bred in 1897. It is a first early and gives a good, heavy crop, but unlike 'Catriona' it is rather susceptible to blight. Epicures should instead grow 'Pink Fir Apple' (£7.50 for a 2kg pack) and 'Charlotte' (£6.75 for 2kg pack). Both are available from Marshalls at marshalls-seeds.co.uk.

THINK ABOUT

* Spring cleaning your house plants, sponging winter dust from the leaves and removing anything that definitely looks dead.

* Pulling dead leaves away from your clumps of bearded iris so that as much light, air and sun as possible can get to the rhizomes.

* Lifting and splitting crowded clumps of snowdrops. When you replant, give them a handful each of bonemeal.

* Mulching round fruit bushes such as currants and gooseberries. I use mushroom compost because, unlike our compost, it is not thick with weed seeds.