Gardening in May: what to plant and tidy up in your garden this month

May is one of the richest times of the year for gardeners; with lush seasonal vegetation, flowers that flood the edges and outdoor spaces that are taken advantage of when the weather improves.

With the month approaching, it’s finally time to move forward with gardening jobs in preparation for summer.

Here are our tips for DIY jobs you can start to improve your garden space. Good luck!

Garden chores to do in May

iris

Elegant floral iris versicolor ‘Algonquin’ flowers in May and June in shallow pond edges and swamps. Tor Garden Plants sells it and a wide range of special and beautiful water irises to plant now.

Harden off dahlias

Around mid-May I start to harden off my dahlias so that they can be planted outside at the end of the month. This year’s big new hope is Dahlia ‘Jomanda’ and ‘Karma Fuchsiana’, both orange-salmon, and both now also available as potted plants from phaasantacreplants.co.uk, if you haven’t been able to get your tubers started earlier.

Cacti and succulents

Cuttings from succulents take easily at this time of year. Pull off an echeveria or pachyphytum leaf and set it aside for a few days to let it become callous, then gently push it into very gritty compost. Soon small growths will appear and you will know that it is rooted.

net profit

Just draping nets over fruit bushes is one way to accidentally catch birds: invest in a good fruit cage from Northernpolytunnels.co.uk or make small cages from sticks of wood and net that you can lift up to harvest.

meadow land

If you seeded a small patch of pasture in late fall or early spring, thin it out now, anywhere seedlings have germinated in thick patches, a few inches apart. You get bigger and healthier plants.

Globe artichokes

This is the moment of the globe artichoke. Steam for 30 minutes, or until the leaves come off easily, then dip in melted butter and lemon juice. Remove winter mulch protection around plants, feed, water and mulch with compost or manure.

pinch beans

Pinch out fava beans as soon as flowers appear to keep blackflies at bay and give the plants some support if they are overhanging. I push a stick into the ground at the end of each row and tie some twine in between.

Grocery stores

Now that the blooming currants are over, ensure good blooms next spring by cutting the flowered shoots back to a strong young shoot further down the stem. Cut out about a third of the oldest stems completely.

Selection of tomatoes

If you plan on planting your tomatoes in pots, consider vintage tall tom pots from long-toms.co.uk. These are made with drainage holes in the sides and need to be buried slightly. The roots then escape from the pots and go in search of moisture. The modern equivalent are Grow Rings, available on Amazon.

Also in May… Beautiful brute

utilities Clematis montana has finished flowering, now is a good time to trim it before it overruns your shed. Trim it all the way to tidy it up, or cut it back hard if necessary. It will be fine, although you may get fewer flowers next year.

Spuds you will like

Now is the time to ground your potatoes to prevent them from turning green. You should also make sure to plant anything that still lingers on the bottom of bags or in egg cartons.

Eucalyptus leaves

Runaway eucalyptus trees can work beautifully as a coppice, and now is the time to do it. Chop yours to the ground now and you’ll soon see a flood of new glaucous foliage. You can repeat every few springs.

Rock away

It’s time to plant new alpine troughs and rock gardens. Add plenty of drainage to the base first, then make a half-grit, half-compost mix. Visit Border Alpines to view a wonderful selection of plants.

Spanish peppers

We are so used to pinching the tops of plants to make them bushy, but peppers don’t need it. Keep squeezing your fingers, otherwise you can delay the first fruit for up to a month. An assortment of plants is still available at seaspringplants.co.uk, although orders have been postponed to mid-May.

beetle mania

Watch out for viburnum beetle larvae, which can severely defoliate plants. They are pale yellow with black markings and now active, so if you see any torn leaves, lift them up and deal with the culprits.

On the edge

It’s asparagus harvest time and if you think you can never have too many special garden tools, it’s time to arm yourself with an asparagus knife, because of its long curved blade. There’s a nice one on worm.co.uk.

Bumblebee on lavender

If you didn’t cut lavender plants after flowering last year, do it now. Bring them in with scissors and remove any old flowers from last year before giving the entire shrub a very light pruning to promote bushy growth.

Stock now

Penstemons benefit from being pruned back now. Last year’s growth has now done its job, protecting them all winter, and while you’re chopping, you can take softwood cuttings and increase your stock. Each cut should be about 4-5 inches long.

Carefully remove the bottom two pairs of leaves and put several cuttings in a pot with compost, water and cover with a clear plastic bag and place in a greenhouse or on a windowsill until rooted.

long legged fig

My fig tree has become leggy and gappy in the middle, and now is the time to prune it back to encourage more growth from the base. Not the whole plant, but a branch or two cut off to the base should encourage a flood of new stems.

Remove Faded Daffodils Heads This Month

Remove heads of faded daffodils and tulips. Next year they will be better if they can put their energy into feeding their bulbs instead of producing seed. Tying up the stems looks crazy – let them die off naturally.

Carrot and stick

At the end of April to the end of May, the carrot flies are on the wing, so if direct sowing the following month, immediately cover your rows with horticultural fleece to repel them.

Planting broad beans in a raised bed

If you have had trouble sowing vegetables this spring, help is available in the form of the plug plants from Boomkwekerij Delfland, which can be bought ready-made by mail order.

May supply would normally be the most numerous of the year as this is the most important month to get your plot planted. However, the nursery will only take new orders from June to catch up on a backlog (biologischeplanten.nl).

Caring Comfrey

Comfrey is nutrient-dense and easy to make into a great—albeit uplifting—organic fertilizer. Buy plants of ‘Bocking 14’ (a sterile variety and therefore not as invasive as comfrey) at organiccatalogue.com

strawberry jars

If you have strawberries in pots, take some to the greenhouse. This ensures early growth and flowers, as long as you leave the greenhouse door open for pollinators to visit.

For later

Chrysanthemums are wonderful late summer cut flowers. I buy rooted cuttings of ‘Allouise Orange’ to plant out once the frost is over (chrysanthemums direct.co.uk).

Wading, lifting, tipping

If your water lilies were under-bloomed last year, it may be time to divide. Wade in, lift, tip from the planting basket then use a knife to divide the rhizomes, making sure they all have a young shoot. Then replant them each in their own basket and place them back in your pond.

box disease

Watch out for signs of fire blight. If you see any affected areas, cut them out and dispose of them from the yard. Feed the affected boxwood plant well, water it all summer and don’t prune it, and there’s a small chance it will outgrow the problem.

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