3 June marks the United Nations’ World Bicycle Day (adopted by the UN in 2018).
5 June marks the UN’s World Environment Day. Celebrated internationally since 1974.
21 June marks the International Day of the Celebration of the Solstice.
- Carefully water new salad & seeded plots.
- Thin fruit – especially apple & plum trees – for bigger fruit & improved crop quality.
- Tomatoes: Regularly remove side-shoots on cordon tomatoes & tie plants to supports. Ensure on cordon tomatoes that their main stem is well-supported. Feed plants regularly with a high-potassium fertiliser.
- Harvest early peas & prepare for a late sowing of an autumn crop.
- Water potato plants for good sized tubers and reduced problems.
- Protect soft fruit from attack by birds by netting securely.
- Strawberries: remove strawberry runners during the early part of the summer to avoid energy being diverted from setting fruit. You can increase your stock by cutting runners and sowing into pots or directly into gaps in late summer/early autumn.
- Gooseberry: Check bushes for sawfly larvae. Start summer pruning of gooseberries, shortening the current season’s growth back to five leaves, and prune out and dispose of any shoots affected by gooseberry mildew. (RHS, The Garden, June 2018, p.29)
- Pinch out tips of figs at the end of June, once shoots have made five leaves.
- Feed fruit & vegetables with liquid fertiliser.
Plant-out tender vegetables
- Plant out sweet corn in several short blocks, spacing plants about 16 inches apart.
- Finish transplanting indoor-grown cucumbers, summer squash, zucchini & winter squash and pumpkin.
- Plant out tender potted pepper plants. Same too for aubergine.
- Leeks, sown in March or April indoors, can now be transplanted outdoors when pencil-thick. Place into 15cm (6″) deep holes & water well.
Sow Directly into prepared ground (Early June)
- Crops such as carrot, beetroot, turnip and radish can be sown direct in June for autumn and early winter harvests.
- Succession-sow small quantities of salad greens and herbs every 2-3 weeks for continuous picking – eg leaf lettuces, rocket, coriander, dill and basil
- Sow at 2 week intervals salad leaves & annual herbs such as dill and coriander.
- Direct-sow carrot cultivars such as ‘Chantenay’ for autumn & winter harvesting (‘Autumn King 2’).
- Sow courgettes (zucchini).
- Florence fennel sown now is less likely to bolt than earlier sowings. Fennel plants mature in 10-14 weeks.
- Squash & pumpkin.
- Continue direct-sowing runner beans & French beans
- Sow fennel & oriental greens such as mizuna & pak choi – sowing now helps reduce the risk of bolting
- Grow lettuce, salad leaf crops & radish to fill gaps between slow-maturing vegetables such as brassicas.
- Strawberry harvest will be finishing in early June.
- Loganberries will be ready to start harvesting early June.
- Early peas.
- Harvest summer radish, salad onions, salad leaves, and broad beans.
- First, second and salad potatoes may be ready for harvest.
Flower / Ornamental Garden: Maintenance
- Deadhead camellias and rhododendrons by carefully pinching off faded flowers by hand, avoiding damaging new growth.
- Finish planting dahlia tubers 4-6 inches deep in well-prepared, enriched beds or containers of compost.
- Divide bearded irises after flowering – replanting sections with at least 2 fans of leaves attached.
- Stake herbaceous perennials – like lilies and tall plants such as delphinium.
- Stake summer flowering bulbs such as gladioli.
- Deadhead shrub roses. Remove suckers from ornamental trees and roses.
- Tie-in climbing and rambling roses as horizontally as possible to encourage better flowering.
- Deadhead perennial flowers – eg delphinium, daisies & lupin – to encourage a second flowering.
- Remove flowerheads from euphorbias, pruning to ground level to encourage strong new growth. Be careful as euphorbia sap is sticky and can cause skin irritation.
- After flowering, cut back oriental poppies for a fresh rosette of growth.
- Prune spring- & early-summer flowering shrubs – eg philadelphus (mock orange).
- Weed regularly and dig out roots of perennial weeds – eg bindweed.
Flower / Ornamental Garden: Sowing & Planting
- Sow for summer colour: there is still time to sow quick-germinating annuals such as cosmos – for flowers lasting well into autumn.
- Sow: winter flowering pansies.
- Sow: biennials such as wallflowers & foxglove to flower next year.
- Plant: Finish planting summer bedding plants and tender perennials. For example, fill gaps in flower beds with long-flowering summer bedding plants – eg cosmos & lobelia.
- Thin direct sowings of hardy annuals & biennials – eg calendula
- Protect flower beds from slugs and snails – especially lilies, delphinium and hostas.
- Some guides suggest to treat invasive weeds – eg bindweed, ground elder – by applying glyphosate gel to their leaves. I find persistence without chemicals also works – but you have to be relentless and pull out as much of it as you can. (This seems to work better with bindweed than with ground elder.)
- Take softwood cuttings from tender plants such as fuchsia and from deciduous shrubs such as buddleja, hydrangea and lavandula. Also suitable for cuttings: spiraea, caryopteris
- Winter savory can be propagated by softwood cuttings in summer.
- Tadpoles will be setting legs and transforming into froglets.
- Many birds are fledging.
- When removing floating aquatic weeds from your pond, don’t remove more than a third as these plants provide shade and shelter to pond life.