What to do in the garden this month: March gardening tips

Welcome to spring! After a long, wet winter, gardeners across the land are rejoicing at the sight of blue skies and longer days. While frost is still a risk, there are ample jobs you can tackle outdoors this month to prepare for the blooming season ahead. 

Once again, it’s time to target any unwanted weeds that may have sprouted over the winter. Gently pulling them now, before they have had a chance to seed, will make the job easier come summer. Adding a layer of mulch will help to supress future weeds and retain moisture, supporting soil health. 

Your lawn may be starting to look a little unruly. Wait until the grass is about 5cm-7cm tall before attempting your first mow of the year. Set your mower to its highest setting for the first cut and remember to rake away clippings afterwards. It’s best to tackle this job when the grass is fully dry to ensure an even cut. Wait a few more weeks until the threat of frost has passed before sowing a new lawn or patching up bald spots.  

Now’s the time to prune any hydrangeas still in need of a chop. While climbing hydrangeas are best pruned in late summer/early autumn, many lacecaps or mopheads perform best when tackled in early spring. Deadhead the flowers and cut stems back to just above the first healthy buds. Cutting some older stems at the base can help to encourage new growth. 

You can deadhead daffodils as they wilt but leave stems and leaves to die back naturally. There is no need to deadhead crocuses. Those planted in containers can be dug up once the foliage has died back and stored in paper bags in a cool, dry place ready for repotting in autumn. Once they’ve stopped flowering, snowdrops can be dug, split, and smaller clumps replanted to give you a bigger spread next year. 

Many varieties of roses will benefit from attention this month and Bord Bia offers some useful tips to help you tackle the job here. Fertilise roses, lawns, and other plants now to give them a boost as they emerge from dormancy. The team in your local garden centre will be able to advise what’s best for your planting scheme.

They will also be able to help you pick some spring colour to suit the size, orientation and location of your garden or outdoor area. Bedding plants, such as Irish-grown pansies, primulas/primroses, carnations, and bellis add a vibrant splash of colour as summer approaches.  

St Patrick’s Day, or the previous weekend, is a great time to sow the first potatoes of the season. Ideally, these will have been chitted (the process of sprouting seeds before planting) but don’t worry if you haven’t started this yet, you can plant them anyway. You’ll find more advice in Bord Bia’s Potato Grow Guide.  

Onion sets are also ready to plant from March, into April. Fertilise the soil with compost and a general fertiliser and push the sets (available online and from garden centres) in rows approximately 25-30cm apart and pushing them down about 1cm, leaving the neck/tufts above the soil. Plant bulbs 10cm apart for larger onions and 5cm apart for a higher yield of smaller onions. The bulbs can be tempting fodder for visiting birds so cover with cloches or mesh for the first month, until well rooted. 

For more helpful Grow Guides, see bordbia.ie.