What to do in the Garden in May


Lawn care



With spring in full swing the lawn will be growing very quickly so it’s best to keep on top of the mowing. It’s easier to mow regularly than mowing through long grass on fewer occasions.

If you haven’t had a chance to mow the lawn recently and it has grown very long it will need mowing twice, once on a high setting and then again on a lower setting to neaten the first cut. Pushing a lawnmower into long grass is bad for the mower and will result in the blunting of blades, clogging of the mower and the possibility of damage to the engine. It will also result in a very rough looking cut.


Moss, debris and ‘thatch’ (dead grass) can build up over the winter, to keep your lawn in top-condition it needs to be removed at least once a year.

If you have a large lawn it may be worth-while hiring a scarifier, otherwise the same job can be done using a wire rake (although it is quite a vigorous task!). Starting at one end of the garden, rake through the grass pulling out the moss or ‘thatch’ as you go. Work your way across the lawn until the whole area has been scarified.


Any moss you remove whilst scarifying can be used to line hanging baskets. Moss is one of the most attractive hanging basket liners and makes side planting easy. It’s recommended that you initially line the basket with plastic and then push the moss in around the outside.



Aerating a lawn is tiring work with a fork but well worth it for a beautiful, green lawn. Start at one end and work your way backwards, pushing the fork into the ground at least every 6 inches. Various aerating products are also available to make the job easier. Repeat this process until the entire lawn has been aerated.


Apply sulphate of iron

Sulphate of iron is the key to an emerald-green, moss-free lawn. Only apply on dull days when rain is forecast within the next few days, an application on a hot day will scorch the grass. Sulphate of iron will give your lawn a black-ish tinge for a few days, in this time it’s important not to walk on it. As soon as it rains and washes the Sulphate of iron in thoroughly, the lawn will take on a beautiful deep-green colour.

Sulphate of iron stains fabric – wear old clothes and remember to take your boots off before you go back in the house!

Remove weeds on paving and gravel

The mild, damp weather in May means weeds are one of the biggest problems, they will be springing up everywhere. Weeds on paving and gravel can be sprayed with herbicide, unless you have an organic garden in which case a combination of hand-weeding and hoeing is best.

Remove algae and moss from paving and steps

Algae can be very slippery when wet and therefore, dangerous on paving and steps. There are chemicals specifically designed to remove algae, or otherwise you can use a scrubbing brush and diluted detergent.

Continue to dead-head spring bedding plants

Spring bedding plants can last right through the summer and look great with summer plants. To keep them looking good, carry on dead-heading and you’ll be rewarded with more and more flowers.

Harden-off summer bedding plants

After your summer bedding plants have been sitting comfortably in a warm greenhouse or conservatory it can be a bit of a shock to them to be planted straight outside where night-time temperatures are a lot colder. To prevent the risk of losses due to planting out, harden them off by leaving them outside in their pots during the day time, only bringing them in at night. This eases them in to outdoor life a lot more gradually, as a result of this you’ll be able to enjoy a healthy display from your plants in the summer.


Plant out summer bedding plants

It’s important to leave your frost tender plants, such as summer bedding, in a sheltered place until all risk of frost has passed. Usually the end of May is a safe time, however they will need to be hardened off first (as above). Once you have planted your bedding give them a generous dose of water to settle them in to their new position.

Tie-in climbing roses

Roses usually start to produce long shoots from May onwards. Any unwanted new growth can be cut off at the base, but good quality shoots on climbing varieties can be trained to the wall replacing very old stems.

Dead-head spring bulbs

Pull the spent flowers off any remaining spring bulbs. To maintain a healthy bulb for next year don’t cut the leaves off. All green parts are still photosynthesising and putting energy into the bulb which will be stored and used next spring.

Move and divide spring bulbs

Where bulbs have naturalised in your garden you may now have a large clump of flowers in one place. Dividing your bulbs means that next year, not only will you have better spacing of flowers, but they will multiply even more.


How to divide bulbs

1. Dig up the entire clump, being careful not damage any of the bulbs with the spade.

2. Carefully separate the bulbs with your hands, try hard not to break any of the roots, stems or leaves.

3. Re-plant straight away, 3 - 4 times the depth of the bulb.

4. Water-in to settle them into place.

Don’t worry if the leaves and stems ‘flop’ after moving, as they slowly die off they will still convert energy to the bulb and will flower again next year.


Plant out tubers

If you have stored tuberous plants, such as Begonias, Cannas or Dahlias over the winter, now’s the time to plant them outside. Tubers should be planted quite shallow - they only need to be covered by about 1 inch of soil. If your tubers have grown shoots, make sure you plant them with the shoots pointing upwards. Once you have planted your tubers give them some water to boost them into action.

Prune Dogwoods

Dogwoods look fabulous in spring with their vibrant coloured stems, that’s why it’s a shame to cut them back too early. Dogwoods don’t always survive a hard prune, so it’s a good idea to leave half of the stems per plant intact and remove the others. The older stems can be removed right at the base where they join on to the root mass and younger, brighter stems should be left until the following year.





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