Jobs for June
June is a wonderful time in the garden, flowers are starting to appear in abundance and there's plenty to harvest in the vegetable patch. 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.
THE FLOWER GARDEN
Sowing and growing
Thin out hardy annuals such as cornflowers, nigellas and English marigolds that will benefit from being spaced 30cm 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).
Next spring's biennials, such as wallflowers and honesty, need time to establish. Both can be sown now, direct into a seedbed, spaced a couple of inches apart. Thin in three or four weeks to 30cm (12in), and transplant to their flowering position in early autumn. If space is short these will be perfectly happy in pots in a sheltered spot until the autumn when they can then be planted in their final positions.
Fill any gaps in your borders with bedding plants, such as salvia, begonias and one of my favourites – pelargoniums. Water them regularly, particularly in drier weather and in the days after planting.
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. Follow the rule of the 4 T’s to succeed with direct sowing – sow into a fine Tilth, at the right Time (when the soil is warm and moist), sowing as Thinly as you can, and then Thin the seedlings to leave them spaced 10-12in (25-30cm) apart.
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.
Bulbs and Tubers
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. These settle in better when already starting to grow.
Lift and divide over-full clumps of bulbs as leaves turn yellow. Replant in fresh soil with added compost.
Stake and tie in dahlias as they grow.
Continue successional planting of gladioli.
Harvesting
Lovely things to pick and arrange from your garden in June:
Lilies and alliums.
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; left to blow about in the wind, the flowering stems will bend and be tricky to use in the vase.
Peonies, penstemons, euphorbia, English garden pinks and alstroemerias.
Roses, philadelphus, Viburnum opulus 'Roseum'.
Perennials, Shrubs and Trees
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.
Strong winds at this time of year can cause quite a bit of damage to taller perennials, so it's essential to keep staking and tying them up to help prevent damage, especially with vulnerable plants such as delphiniums and peonies.
Metal plant supports are ideal for use in borders and at the edge of lawns and paths, and flower rings are also great for supporting plants such as freesias and chrysanths.
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.
Divide primulas, including primroses, cowslips and the more unusual varieties such as 'Gold Lace' polyanthus and the beautiful, green-flowered 'Francesca'.
Huge-flowered oriental poppies, such as 'Patty's Plum', have finished flowering. Cut everything back to ground level, leaving no foliage standing. Feed with poultry manure pellets 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.
Take cuttings of lavender.
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.
THE KITCHEN GARDEN
Vegetables
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.
A second sowing of courgettes can be done now.
Continue successional sowings of carrots, French beans, Borlotti beans and sugar snap peas.
Sow chicory direct into the garden, to give you delicious meals right through the winter. Choose varieties such as 'Treviso', 'Sugar Loaf', or the F1 hybrid, 'Cesare', and sow widely and evenly into soil with plenty of organic matter added. The seeds should germinate within a couple of weeks, then thin the seedlings to 15cm (6in) spacing to allow room to grow on, transplanting them a month later to 30cm (1ft) apart.
Enclose your carrot beds in Enviromesh or fleece. As long as you surround your patch in insect protection to a metre in height, you don't need to cover the roof. The carrot fly flies near the ground and can’t hop up and over.
Continue with successional sowings of radishes, lettuce and salad leaves.
Sow seeds of herbs now, including coriander and parsley, chives and dill.
Water a patch of soil in the garden or greenhouse and direct sow basil, scattering the seed widely so you won’t need to thin. Water again every couple of days if there’s no rain, and you should see germination in about 10 days.
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.
Fruit
If your strawberries need a little help ripening, bring them in to the warmth of the greenhouse.
Thin out fruit trees to prevent broken branches and help the remaining fruit grow all the larger.
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.
OTHER JOBS
As the weather gets warmer, pond weed can quickly get out of control if left. It’s an easy and fun job removing it, best done with a small net or old kitchen sieve.
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.
Check plants regularly for signs of pests and remove any dead or diseased leaves.
Plant tagetes to deter whitefly.
If temperatures are high, increase greenhouse shading and damp down the greenhouse floor every morning. Water pots and growing bags daily, but avoid doing this in the middle of the day.
Pests and Diseases
Keep your eyes peeled for vine weevil. The larvae feed on plant roots particularly in pots, the adults (a scaly-looking black beetle) on the leaves, so check your pots regularly so they don’t destroy all your well-made plans for summer containers. Water on a biological control if you see any beetle or larvae signs.
Look out for woolly aphid on fruit trees, and spray any with soapy water.
There's plenty of pollen beetle around at the moment – little black beetles that accumulate on highly scented flowers such as sweet peas. Don’t let this stop you picking them, as sweet peas need to be picked, picked, picked to keep them flowering. If you bring in a bunch with beetles on, put them in a dark room with the window open. The beetles will fly towards the light and out the window.
Consider introducing a variety of plants into your garden to attract beneficial insects and wildlife to help develop a balance between pests and predators.