01/06/2026
June is a wonderful time in the garden, an abundance of flowers are starting to appear and there's plenty of veg to harvest. Keep on top of supporting your plants and keep an eye out for cold nights at this time of year as some plants will still need plenty of protection.
It's pretty safe to assume the frosts are well behind us (although they can still catch us out), so now is the time to plant out those varieties that have been brought on in the greenhouse. Make sure your plants are well established before putting them outside. It’s an idea to still have some fleece or newspaper to hand to cover plants outside should a night frost be forecast.
Thin out hardy annuals. Be tough– most of them (cornflowers, nigellas and English marigolds included) benefit from spacing 30cm (12in) apart. More room means more root, leaves and photosynthesis, better flowers and a longer life. Use pea sticks to support taller varieties such as cornflowers and Ammi majus (Bishop’s Flower).
Fill any gaps in your borders with bedding plants, such as salvia, begonias and one of my favourites – cosmos. Water regularly, especially in drier weather and in the days after planting. Watering in these hotter months is best done in the morning or evening, to avoid scorching plants in the heat of the day.
Sow poppies – if sown direct now, many varieties flower within eight weeks. Poppies prefer to be sown direct rather than into a seed tray as they hate root disturbance.
Deadheading flowers as they go over this month can result in a second flowering. This is particularly worth doing for your hardy and half-hardy annuals, to ensure their one and only season lasts as long as possible. Perennials will also benefit, for example later in the month lupins and delphiniums can be deadheaded to encourage a second flowering later in the summer.
Lift and store spring bulbs for next year and divide any clumps that are to stay in situ.
Plant autumn-flowering bulbs, such as colchicums and hardy cyclamen.
Stake and tie in dahlias as they grow.
Continue successional planting of gladioli.
Sweet peas will be starting to flower now, so pick, pick, pick to keep them going as long as possible, and give them a weekly liquid potash-rich feed. Tie them in as often as you can; if they are left to blow about in the wind, the flowering stems will bend making them more difficult to put in a vase.
Keep weeding and deadheading to ensure borders stay looking at their best. If you didn’t do so in the spring, apply a mulch on moist soil. Watch out for aphids on susceptible plants, eg lupins. Spray with a soap-based insecticide if necessary.
Cut back pulmonarias as they may well be looking a little sick from mildew by now. Cut back all the leaves, then feed with a slow-release fertiliser. Divide congested clumps and replant now. Water well if the soil is dry.
Huge-flowered oriental poppies, such as the beautiful, dusky purple 'Patty's Plum', have finished flowering. Cut everything back to ground level, leaving no foliage standing. Feed, mulch and give them a good dousing of water and the new foliage will grow back soon.
Cut back delphiniums, right to the ground, leaves as well as old flower spikes. If you do this now, almost all plants will give you a second flush of flowers in August and September.
Prune back sedums – this will stop the centre becoming bare as the stems flop outwards. Cut the stems back by about a third to stop this outward sagging.
Deadhead roses as often as you can now they're flowering at full tilt. Snip off their browning heads to a bud or leaf below to help promote the formation of axillary buds, then more flowers will follow. Rambling and climbing roses will be growing rapidly so tie them in regularly as close to the horizontal as possible.
Spring shrubs such as Weigela and philadelphus that have finished flowering can be pruned now. If your plants are old and quite congested, then it is a good time to remove some of the older stems near ground level.
Direct sow brassicas and leeks for winter harvest.
Bring your beans and tomatoes out of the greenhouse and plant them at the base of pre-prepared supports. The key to ensuring the best harvests of both, is to keep the roots well watered.
Pinch out all side shoots of your cordon tomatoes, and support them with a cane at their side to tie them into on a regular basis.
A second sowing of courgettes can be done now. A good tip is to plant the seeds in pairs and then remove the weaker seedling as they come through.
Continue successional sowings of carrots
Tie in cucumbers .
Grow edibles and flowers together as companion planting.
Keep doing successional sowings of radishes, lettuce and salad leaves.
Sow seeds of herbs now, including coriander and parsley, chives and dill.
At this time of year, stems of mint will produce roots within a week if cut and placed in water. They can then be planted up, ideally in pots to contain their spread.
If your strawberries need a little help ripening, bring them in to the warmth of the greenhouse. Another benefit of doing this is to protect against birds and other fruit-loving creatures.
Thin out fruit trees to prevent broken branches and help the remaining fruit grow all the larger.
If not already done, cover fruit with netting.
Thin gooseberries – while they are still unripe, remove every other fruit. This allows the fruit that remains to swell and sweeten to harvest in about a month’s time.
Start to plant your summer and autumn-flowering containers.
Mow and edge your lawn – even if you don't have time for any other jobs outside, it will make your garden look much better.
Summer rainfall is rarely enough to keep compost moist in containers, so warm weather means daily watering of pots and hanging baskets. If yours are already dry, rehydrate the compost by plunging the whole thing in water for an hour or so.
Take cuttings from hydrangeas, fuchsias, pelargoniums, osteospermums, marguerites, coleus and verbena. Water well with a deluge rather than a sprinkle as this will encourage to plant roots to go down rather than surface rooting.
