At a glance
June is the month when the UK garden moves into full production and the pace of work increases significantly. Long days, warm soil and settled weather create ideal growing conditions – but also ideal conditions for pests, weeds and the water stress that can set back crops sown and planted through spring. The gardener who stays on top of watering, feeding and pest control in June sets up a productive July and August; the one who lets things slide in June spends the rest of the summer catching up.
The gardening calendar accelerates in June. Strawberries need daily checking as they ripen, early potatoes are ready for lifting, successional sowings of salads and beans keep the harvest window open, and tender plants that have been hardening off outdoors can finally be planted out with frost no longer a concern. The jobs list is long but mostly quick – June gardening is less about big projects and more about consistent daily attention to a garden at its most active.
Vegetables and fruit
Thin out seedlings of carrots, parsnips, beetroot and turnips sown in April and May to their final spacings. Delaying thinning beyond this point means the roots compete with each other and produce small, misshapen crops. Use thinnings of beetroot and carrots as baby salad leaves rather than discarding them.
Earth up potatoes as they grow, pulling soil up around the stems to prevent greening of developing tubers. First early varieties planted in March will be ready for lifting from mid-June – check by feeling gently under a plant for egg-sized tubers. Do not wait for the foliage to die back; early potatoes are harvested while the tops are still green. Pinch out the growing tips of broad beans once they are in full flower to discourage blackfly, which congregate on the soft new growth.
Thin fruitlets on plum and apple trees if they have set a heavy crop – June drop (when trees naturally shed some fruitlets) will reduce numbers, but supplementary hand-thinning to one fruit per cluster produces larger, better-flavoured fruit and prevents branch breakage under excessive weight. Strawberries require daily picking as fruit ripens – fruit left on the plant overripens within a day in warm June weather.
Flowers and ornamentals
Deadhead roses, dahlias, sweet peas and all repeat-flowering perennials regularly – removing spent flowers prevents seed formation and redirects the plant’s energy into producing more blooms. Sweet peas in particular need deadheading every two to three days to keep them flowering prolifically; any pods allowed to form signal the plant to stop producing flowers entirely.
Stake tall perennials before they need it – a dahlia staked before it falls over looks natural; one staked after looks propped up. Support dahlias, delphiniums and tall asters with sturdy canes or purpose-made peony rings placed over the clump as it grows. Pinch out the growing tips of dahlias that were planted in May to encourage bushy, multi-stemmed plants rather than single tall stems with fewer flowers.
Take softwood cuttings of penstemons, salvias, fuchsias and other tender perennials in early June while the new growth is soft and roots readily. June cuttings taken from the current season’s growth root quickly in warm conditions and produce rooted plants by September, providing insurance against winter losses.
Lawn care
Mow regularly through June – in good growing conditions the lawn may need cutting twice a week to stay tidy. Raise the mowing height slightly compared to spring cuts; a slightly longer sward of around 4cm holds moisture better in dry spells and stays greener under stress. Do not collect all clippings – leaving some on the lawn in dry weather returns moisture and nutrients to the surface. Apply a summer lawn feed if the lawn looks pale or slow-growing, but avoid high-nitrogen feeds in very dry conditions as they can scorch.
Treat lawn weeds with a selective lawn weedkiller in June while they are actively growing – this is the most effective time of year for weed control. Do not apply weedkiller in drought conditions or immediately before rain.
Watering and feeding
Watering becomes the most time-consuming June task in dry years. Water deeply and infrequently rather than little and often – this encourages roots to grow deep where moisture is more consistent. A thorough soaking every three to four days in dry weather is more beneficial than a light sprinkle every day. Focus water on newly planted items, fruiting crops and anything in containers, which dry out fastest. Established shrubs and perennials in borders rarely need watering in June unless conditions are exceptionally dry.
Feed tomatoes, peppers, aubergines and other fruiting crops with a high-potassium liquid feed once the first flowers appear – every seven to ten days through the fruiting season. Feed dahlias and sweet peas with the same high-potassium feed to support prolific flowering. Continue feeding roses with a specialist rose fertiliser after the first flush of flowers to encourage repeat blooming.
Pests and problems
Aphids reach peak numbers in June. Check the growing tips of roses, broad beans, lupins and nasturtiums regularly and deal with colonies early before they spread. Encouraging garden birds is one of the most effective long-term aphid controls – blue tits, sparrows and wrens consume large quantities of aphids when feeding chicks in June.
Powdery mildew begins appearing on courgettes, cucumbers, phlox and roses in June, particularly in dry conditions at the roots combined with humid air. Improving airflow by thinning crowded growth, watering at the roots rather than overhead, and removing affected leaves promptly reduces spread significantly. Slug damage peaks on hostas, delphiniums and young vegetable seedlings after wet periods – check and treat regularly through the month.
Wildlife tasks
June is peak nesting season for garden birds – avoid cutting back hedges or dense shrubs until after nesting has finished in late July. Keep the bird bath topped up in warm weather as natural water sources dry out. Leave a patch of nettles uncut if possible – they are the sole larval food plant for several butterfly species including small tortoiseshell, comma and red admiral, all of which will be laying eggs in June.
June checklist
Mulch around plants in early June before the soil dries out. A 5-7cm layer of compost or bark applied while the soil is still moist from spring rain locks that moisture in for weeks. Applied to dry soil, mulch has far less benefit. June is the last good opportunity to mulch before summer heat arrives – doing it now reduces watering requirements significantly through July and August.
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