March gardening tips

Tiffany Daneff / 23 March 2017 ( 19 March 2020 )

Find out what needs doing in the flower bed and vegetable patch in March, plus what general maintenance needs doing to prepare your garden for summer.

In the flower garden

Sow flower seeds for summer

Hardy annuals can be sown in trays indoors or under glass now but unless you live somewhere mild it’s a bit early for half hardies.

There’s nothing more depressing than seeds that fail and these should deliver: cerinthe major ‘purpurascens’, cornflowers, borage (great for bees and decorating drinks) and viper’s bugloss (also great for bees and for butterflies).

If seed trays have been stored somewhere outdoors or weren’t washed when you put them away give them a good wash and brush up with hot soapy water and don’t think you’ll save money by using old compost or earth – you’ll regret it when seeds shrivel and die.

Use large trays, fill with seed compost to near the top and water with a can with a fine rose or stand in a sink until the tray’s absorbed moisture. Don’t use water from the butt as this can lead to disease and try to use lukewarm rather than freezing cold water.

Sprinkle over seeds as sparingly as you can manage and use a sieve to sprinkle of a light layer of dry compost. Sit somewhere light and neither too hot nor too cold. You want an even temperature around 18 deg C or 64 deg F. Some people like to cover the tray with glass or a clear polythene. You should see results in a week or two.

Once the seeds germinate remove any covers or you’ll get condensation and rot. Whilst you are waiting watch that the compost doesn’t dry out but don’t overwater either. Aim for a consistently moist compost.

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Prune clematis

Prune late summer-flowering and fast-growing clematis, like jackmanii and viticella types. These flower on the current season’s growth so should be pruned in late winter or early spring just when you can see the new buds beginning to make their move. They can be cut back hard (take them to a couple of good buds about six inches to a foot above ground level) as they’ll quickly put on new growth from the base ready to flower in late summer. Don’t be tempted to leave them unchecked as they’ll only carry on growing until next season and you’ll end up with the typical unloved clematis cliché of a top heavy plant with loads of action miles above your head and little bare stems at eye level. (And twice as hard a job to tame it.)

If yours was only planted last year prune back hard to one foot above ground to encourage more shoots to help give a nice shaped plant and one that you can then fan out and tie in to supports.

Feed roses

If you haven’t already done so give roses their first feed of the year. Use a tailored rose feed as they need the correct mix of nutrients. And don’t think you’ll be doing them a favour by over feeding. You’ll end up with too much sappy soft growth that makes them less able to withstand pests. Feed again in April/May and, if you want, they can have a final feed in July but no later or that soft wood will make them vulnerable to winter cold.

Mulch borders

What you mulch with will depend both on what you have to hand and on what condition your soil is in. Hard clay soils can be opened up by digging in or mulching with composted bark or well-rotted manure or grit. Avoiding walking on the soil which only compacts the soil even more, by spreading your weight across a board. Sandy soils also benefit from annual applications of well-rotted manure, home compost and other organic matter.

Find out more about mulching to save moisture

Flower garden maintenance

Cut off old hellebore leaves to stop disease and to show off fresh new flowers.

Dead head daffodils by cutting flower stems to the base but let foliage remain to help build up energy stores in the bulb. They’ll also benefit from a liquid feed every other week and try to avoid them drying out for a month or so.

Prune outdoor fuchsias back to one or two buds on each shoot, ie about four inches above ground level cutting to just above a pair of buds. This will encourage new shoots.

In the vegetable plot

Clear up the vegetable patch

If you’re keen to get started now’s a good time to weed beds, clear away old debris, netting, bean supports and the like and to stand back and survey with pleasure a clean, raked surface.

What to plant in March

It’s still early to plant vegetables unless you live in a warm area in which case you may want to be getting on with sowing carrots, lettuces and peas.

Dig a bean trench

A wheelbarrow of part composted kitchen waste can be wheeled to where you want to grow any greedy plants like beans. Dig a trench a couple of feet deep, fork over the base to loosen the soil, tip in the organic matter and mix in the previously dug out soil. If you’re me it’s worth putting in markers, or even erecting your bean poles, so you don’t forget where the treasure’s hidden when it comes to planting time. Leave a good couple of weeks before you sow your seeds.

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Check houseplants. When you see growth starting again it's time to check your houseplants. Some may just need a tidy up, clearing away dead leaves and debris and a bit of a prune to get it back into shape. If roots are appearing through the base it’s a sign they need repotting. If you cant see the roots, but it’s a while since they were repotted, try to loosen the plug of earth out of the pot and see if the roots are circling as if desperate to get out. If so it’s time to repot. 

Ideally, water plants a few days before repotting. Use washed pots, one size larger than the existing pot, and fresh clean potting compost – whichever is correct for the plant. Some plants like a lighter mix so I tend to mix up my own soil for each plant using a combination of potting compost, sand and perlite as necessary. 

You can add water retaining gel granules if you like and some plants benefit from a topping of grit.  

If the plant’s just not going to come out of the pot you can try to eke out a little more time by top dressing. To do this carefully scrape off an inch or so from the top of the old soil, avoiding damaging the roots, and replace with fresh new potting compost. Water pots well and drain. Avoid putting newly repotted plants in direct sunlight but let them recover slowly. 

After a week or so they should be nicely settled in.

Last chance to…

  • Divide clumps of congested snowdrops
  • Plant out winter forced bulbs such as daffodils
  • Chop away dead foliage from perennials and grasses before the new growth really gets going
  • Cut back cornus and salix which are grown for colourful winter stems 
  • Chit potatoes – large egg trays are perfect for this
  • Deadhead and prune hydrangeas before the sap starts to rise
  • Prune winter-flowering jasmine, cutting last year’s growth to a good sideshoot
  • Lift and divide congested perennials before they grow away with increased warmth and light
  • Prune bush and climbing roses
  • Plant summer flowering bulbs like lilies

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The opinions expressed are those of the author and are not held by Saga unless specifically stated.

The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.