March tasks in the garden

March tasks in the garden

Make the most of any nice days to tidy up the garden, splitting perennials & pruning shrubs (except early flowering shrubs) that are getting out of hand. Rainy days can be spent sowing ornamental & vegetable seeds, or taking a trip out to the garden centre to get inspiration & to see what new plants are available. We always have a wide selection of seasonal flowering shrubs & plants to brighten up your garden at this time of year or potted flowering bulbs to bring immediate colour to your outdoor space.

Garden Pruning

Prune Mahonia in March

  • March is a good month for pruning. You can prune your mahonias & heathers now but be careful not to prune your heathers back into the old wood.
  • Prune heathers - Cut off what grew last season. Prune the bushes into a spherical shape but never back to the bare wood as it is unlikely that they will shoot from there.
  • Prune Hydrangea paniculata & macrophylla flower heads back to a strong pair of buds.
  • Give your honeysuckle a new lease of life by pruning it back hard.
  • Pruning climbing roses - If it is already a sizeable bush, you should prune off a few of the oldest branches. Cut the others back if they have got too long, this encourages the formation of fresh shoots. Leave the rest. Branches which are bent horizontally to some extent give the most flowering shoots, which is why the fan shape is particularly popular when fixing climbing roses.
  • Prune summer flowering shrubs such as Lavatera, Buddleja & Caryopteris.
  • Coppice shrubs for colourful stems or foliage such as Cornus, Salix and Eucalyptus.
  • Prune shrub roses - Prune shrub roses down to between ten and fifteen centimetres above the ground when there is no frost. Prune them short to remove disease spores that can survive on the branches. Only retain strong shoots & prune just above the outward-pointing buds to create an open branched structure.

Planting & Sowing

Plant biennials like Silene in March

  • Plant biennials - Plant varieties such as daisies (Bellis), wallflowers, pansies, forget-me-nots, Silene. These varieties produce a leaf rosette in the first year and flower in the second year. They are a perfect addition to annuals and perennials.
  • Hardy annuals can be sown direct into the soil where they are going to flower from mid-March including the Sweetpea (Lathyrus). From mid-March you can also sow summer flowers outside in a cold frame.
  • Start canna, begonia & dahlias into growth and place them in a sunny spot.
  • As the soil begins to warm it is also time to plant shallots, onion sets, early potatoes, leeks, parsnips, broad beans & peas to name but a few! Vegetables sown last month undercover can also be planted out now & covered with a cloche to harden them off. Chitted early potatoes are also ready to be planted.
  • Pot up last years tender perennial cuttings such as penstemons & hanging basket plants.
  • There are a large number of vegetable seeds which can be sown this month including cucumbers, aubergines, tomatoes, peppers. Use a heated propagator or sunny windowsill.
  • Plant (replant) deciduous trees and shrubs - A lot of trees and shrubs are about to start to put out shoots. This will mean that they will grow particularly well and powerfully after planting. Plants grown in containers (pots) can be planted all year round.
  • Plant grapes - This can be done with (pot-grown) grapes all year round, but if you plant now, a grape will take particularly easily. This also applies to blackberries and related varieties such as the loganberry.
  • Plant roses - To plant roses dig a sizeable hole and enrich the soil going into it with plenty of nutrients. Roses are hungry plants.
  • Planting time from the end of March - Shrubs and perennials which flower in the summer and beyond should ideally be planted now to give them time to get established.

Plant a hedge

  • March is an excellent time to plant hedges.
  • You should work with a five plants per linear metre, (with a twenty centimetre gap between each plant).
  • If you are creating a double hedge where the plants are staggered in two rows, you can plant with a gap of thirty centimetres and you will need six to eight plants per linear metre.
  • For low hedges like Buxus you should plant so that the plants just touch. You will then need eight to ten plants per linear metre.
  • Always make sizeable holes and enrich the soil in the planting holes.

Garden Maintenance

Topdress indoor & outdoor container plants in March

  • Repot or topdress indoor & outdoor container plants to give them a boost & water regularly now.
  • Water plants in acid soil - In March plants which like acid soil have a particular need for water. So give varieties such as Pieris, Rhododendron and bilberries extra water this month.
  • Tidy up your ornamental grasses by cutting them back & removing any dead sections.
  • Now the sun is getting stronger & daylength is increasing, house plants will need to be watered regularly - start them off with a half-strength feed too.
  • Nutrients are very important for a healthy garden, so definitely don't forget to fertilize.
  • March is a very good time for planting and replanting - Pick out which perennials flowered less last year, they age over time and grow less vigorously at the centre. You can fix this for many varieties by dividing or separating the plants every three to four years. Enrich the soil in the new location and plant out the young edge parts you have separated off.
  • Nature is awakening, and so are slugs and snails. Start fighting them before they can attack your plants. Slugs are mainly nocturnal. You can catch them by hand during their night-time feeding expeditions. There are also environmentally-friendly slug pellets which are not hazardous to other animals (or humans). The other advantage of these is that the dying slugs retreat underground, so you do not need to clear up dead slugs.
  • Remove winter protection - Remove protective layers of organic material from perennials. Ensure that you do not damage any young shoots (tips). Take care not to walk on areas where there are bulbs in the soil. Remove plastic bags or other winter protection from the crown of standard roses.
  • Weed vigorously - Weeds grow tirelessly & it is best to remove as many as possible before the seeds can form. This happens more quickly than you think, hoe on dry days & the weeds will die through lack of moisture. Eradicate stubborn weeds thoroughly & remember not to compost them.


  • Set the lawnmower a bit higher than normal and do not mow if the weather is wet. Remove the cuttings. They can go on the compost heap or in thin layers as mulch between the border plants.
  • Restore the lawn - A lawn restoring kit is ideal for giving new, dark green life to your lawn. You can do it in a few quick steps, without digging and with aeration. March is an excellent time to sow a new lawn or lay new turf.
  • If you have problems with moss you can alleviate this in the short term by applying a moss killer then rake or scarify & reseed. It may be caused by poor drainage which needs to be remedied to get long term control.

Ponds & Water Features

Water temperatures are probably still quite low in March but it is worth doing a few maintenance tasks now although fish activity will be low until the temperature is above 10°C.

  • Remove pond netting that was in place to protect your pond from leaves. Pond netting that is left in place to protect the pond fish from predators should be checked over to ensure it is still secure & has not become brittle – replace if necessary.
  • March/April is a good time to divide & replant pond plants so ensure you have baskets, liners & aquatic compost ready for a nice day.
  • Check out & clean any equipment such as pumps, filters & UV lamps, carefully cleaning the quartz sleeve & replacing the UV bulb if it has been in continual use for 12 months.

Profile Image Angela Slater

Angela Slater

Daughter of a farmer and market gardener so have always had a connection with the outdoors, whether it was keeping animals or producing fruit, vegetables and cut flowers. Along with my work at Hayes Garden World I also have a smallholding, mainly breeding rare breed pigs. I gained an HND and BSc in Conservation and Environmental Land Management, as a result I am an ardent environmentalist and have a keen interest in environmentally friendly gardening. In my time at Hayes I worked for several years in the Outdoor Plant and Houseplant areas.