March in the garden

With the arrival of spring, there is plenty to do in the garden in March. The days are longer and warmer, hopefully the risk of frost will have passed by the end of the month, and there are plenty of jobs to do in the garden, greenhouse and vegetable plot. Seed sowing really starts to get underway and you'll want to plant roses and lift and divide perennial plants.

The cutting garden

Sowing & growing

March is the time for sowing your hardy annual seeds under cover. If you have a greenhouse, windowsill or conservatory, you can sow nearly everything in our range of hardy annual seeds.
You can sow some half-hardy annuals too, but wait until the middle of the month when the light levels are better and the nights are less cold.
Sow perennials.
Pinch out tips of winter-sown sweet peas to encourage sideshoots.
Prepare areas in flowerbeds ready for direct sowing hardy annuals in later March through to April.
The end of the month is the time for mass pricking out of annual seedlings. Transplant everything that has formed its true leaves (recognisably like that of the parent plant) into their own individual pot. Take care to get right below each baby plant and lift out the whole of its root with a dibber or stiff label. Handle everything by its leaves, not stem, which bruises very easily.
Take chrysanthemum cuttings (read our chrysanthemum growing guide).
Pot on rooted cuttings of tender perennial plants taken last summer.
Take cuttings of perennials – basal cuttings of phlox, delphiniums and other early-sprouting perennials.

Bulbs & tubers

Plant summer-flowering bulbs such as lilies, gladioli, freesias, crocosmia, etc.
Lift snowdrops and aconites and divide them, in the green when they are just going over.
Plant dahlia tubers in pots under cover. If you only have one or two, plant them individually into a three-litre pot, so they can grow on happily until the frosts are finished and they can be planted in the garden. If you have lots, lay them out in a shallow tray, packed in tight, and cover the tubers with moist compost. They’ll start to sprout in a few weeks and you can then take cuttings.
Later in the month, start a regime of deadheading spring bulbs (e.g. narcissi, muscari and tulips) as the flowers finish. Leave the foliage to die back naturally to feed the bulb for next spring.

Harvesting

Lovely things to pick and arrange from your garden in March:

Bulbs: narcissi, muscari (grape hyacinths), hyacinths, early tulips eg ‘Purissima’, plus freesias and anemones under cover.
Hardy annuals: Euphorbia oblongata and, by the end of the month, cerinthe and schizanthus (inside).
Biennials: honesty and wallflowers.
Perennials: artichoke leaves, hellebores and polyanthus, plus alstroemerias (under cover).

Perennials, shrubs & trees

Pruning & tidying

Cut down old growth of perennials and grasses left over winter.
If soil is workable, dig in a layer of compost or manure, and work in a slow-release fertiliser such as comfrey pellets, chicken manure, or fish, blood and bone.
Weeds will have started to grow, so keep removing them whenever you can.
Split polyanthus after flowering.
Lift and divide your summer-flowering perennials – you can tell which ones you need to attend to by the large clumps that are pushing outwards from the ground with fresh young shoots at the edge of the clump.
Prune shrub roses – remove all dead and crossing wood on your rose bushes and cut the rest back by at least a half, aiming to cut just above an outward-facing bud.
Later in the month, clip box topiary and hedging in to shape if it looks unlikely that we’ll be having any hard frosts, at least in the South, so the danger of scorching new growth will hopefully have passed.
Prune young hedges – cut one or two-year-old hedges back by a third. This might feel brutal when you’re desperate for new growth, but will make a better hedge – thick and strong, even at the base, rather than one that is left tall and gangly with gaps at ground level.
Continue to deadhead hydrangeas before new growth appears. Cut to about one third of last season's growth.
Prune forsythia as soon as they have finished flowering, cutting back to strong, young shoots.

Planting

Plant a new hedge – now is a good time, particularly for a mixed native or hawthorn hedge. On heavy soils, trials have proven that plants establish better from planting now than they do in autumn or winter, when the roots can sit and sulk in the cold.
Plant herbaceous perennials including those for picking, e.g. delphiniums.
Order and plant bare root roses – much cheaper and often stronger growers than pot-grown plants. You can plant bare root roses in March, but wait till there is no frost on the ground. Or you can pot up your bare root roses into large pots to grow on and plant them into the garden almost any time – as long as you keep them well watered.

The kitchen garden

Vegetables

At last you can get going on your veg. It’s so exciting, especially if you love sowing seeds and messing about in the potting shed or greenhouse.

It's your last chance to sow fruiting half-hardy vegetables, e.g. tomatoes.
Sow courgettes, leeks, peas, beetroot and cucumbers under cover.
Sow perennial veg seeds, e.g. globe artichokes.
Plant asparagus crowns.
Sow broad beans direct outside.
Cover soil with plastic to dry it out, then direct sow carrots, parsnips and radishes.
Plant Early potatoes.
Plant one onion set (or garlic clove) per cell in a modular tray. Grow them somewhere bright but cool, such as a greenhouse, until the roots show at the holes in the bottom of each cell. They’ll be ready for planting in the garden in about a month, and will get off to a flying start from this strong root system.
Thin your carrot seedlings to achieve decent-size carrots, best done in the evening when fewer carrot flies are around.

Salad & herbs

Sow salad leaves – it's time to plant your salad crops. Lettuce (mizuna, salad rocket, green oak leaf lettuce) and hardy herbs (coriander, flat-leaf Parsley 'Gigante di Napoli’, and garlic chives) can be sown into gutters under cover.
Sow dill, fennel and French sorrel under cover.
You can also direct sow chervil, chives and sage.
Plant up pots of mint, tarragon, thyme and rosemary.
Divide chives – lift large clumps with a fork and divide into smaller clumps, into soil that has been revitalizes with organic matter.

Fruit

On cold nights, ensure that you protect your fruit blossom from late frosts by covering them with fleece.
You can still plant fruit trees and bushes, and you can still prune your fruit trees too.
Start to harvest early rhubarb – pick the stems of varieties such as ‘Timperley Early’ with a firm tug, rather than cutting them from the plant. Cover midseason rhubarb plants, eg ‘Stockbridge Arrow’, with forcers. This will elongate, tenderise and sweeten their stems.

Harvesting

Here's what you could be picking and eating this time next year or, if you’re an old hand, already are:

Brassicas: Brussels sprouts, red and green cabbages, kale, forced sea kale, cauliflower, Cima di Rapa, and purple and white sprouting broccoli.
Roots: Jerusalem artichokes and parsnips.
Salad crops: salad leaves and overwintered lettuce and pea tips.
Edible flowers: Viola ‘Heartsease’ and primroses.
Leafy greens: chard, perpetual and true spinach.
Stems: leeks, cardoons and rhubarb.
Herbs: parsley, chervil, coriander, winter savory, rosemary, sage, bay, lovage, fennel and thyme.
Fruit: rhubarb.

Other jobs

Top-dress pots. Revitalise permanently planted pots by scraping out the top layer of old compost to a depth of 2-3in (5-7.5cm) and adding the same amount of fresh. Fork it into the old compost surface.
If you haven’t already got one, invest in a water butt to catch the spring rain in preparation for dryer months ahead.
Make or buy a cold frame and/or compost bin.
Reactivate your compost heap – take advantage of any warmer, drier weather and turn the whole thing into a new bin and water on a compost activator, such as comfrey juice or seaweed.
Water indoor plants regularly now the weather is warmer.
Last chance to harvest hazel or silver birch for pea sticks and garden supports before everything breaks into leaf.
Make grand plans for your garden and put them in to action. Work out how you are going to achieve all you have been thinking about during the winter months. Order seedlings/plugs to save time.

In the greenhouse

Prepare for the spring rush – empty your greenhouse and thoroughly clean inside, pressure washing the frame, staging and glazing.
Bring bags of compost into the greenhouse to warm up for a week or two before you start sowing.
Start forcing potatoes.
Monitor temperatures with a max-min thermometer to ensure heaters are working efficiently.

Tidy & mend

Start mulching bare soil. Use at least a couple of inches of green waste from your local council. After a warm spell, it’s a good time to jump in before weed starts to germinate.
Put stakes and other plant supports in place before the new growth really needs them.
Check mowers are working, and service if necessary.
Re-seed bare patches on the lawn and, if grass starts growing, start to cut regularly on dry days. Repair damage to lawn edges. For new lawns, either sow lawn seed now on well prepared soil and keep the soil moist whilst the seed is germinating, or lay new turf and again keep it moist until established.

Wildlife & pests

Keep an eye out for signs of slugs and snails. Put slug prevention in place, especially around young vulnerable shoots.
If weather is mild, keep vigilant for pests and diseases.
Keep providing birds with fresh water and food. Avoid big pieces that fledglings may choke on.
Spring-flowering plants bring valuable early nectar for insects. Think about introducing Ornamental cherry trees, forsythia, ribes, mahonia or sarcococca or some of our native plants, such as blackthorn and wild cherry.
Consider buying and hanging a bee nesting box.