What to do in the garden in June? Plant out all your summer bedding plants into borders, containers and hanging baskets. Tender vegetable plants such as tomatoes, courgettes and sweetcorn can also be planted outside now. Dead-head your roses if they are repeat-flowering types, to encourage more flowers. Lift and divide clumps of snowdrops and bluebells once the leaves start to yellow. Start to harvest your early potatoes towards the end of the month. Support the growth on tall perennial plants to prevent them getting damaged by the wind.