Plant out summer bedding once the risk of frost has passed. Keep an eye on the weather forecast, and protect with horticultural fleece if necessary.
Dahlia plants can be planted out at the end of the month. Stake any herbaceous plants that will flop over or be damaged by high winds. Evergreen hedges can be cut from this month, but check for nesting birds before getting the shears or hedgecutter out.
Prune spring-flowering shrubs such as Choisya and Ribes after flowering. Regularly tie in climbers to their supports as new growth extends. Cut lawns weekly, and apply a high nitrogen lawn feed unless drought conditions persist. Treat broad leaved lawn weeds with a selective herbicide. Lightly trim box hedges and topiary towards the end of the month, and keep checking for those pesky box tree caterpillars.
Hang pheromone traps in apple trees to check for codling moths. Watch out for viburnum beetle and lily beetle grubs. Keep earthing up your potatoes, and plant any that are still remaining. Put straw around your strawberry plants before the fruit trusses begin to bend with the weight of fruit, then net to protect fruit from hungry birds.
French and runner beans, and sweetcorn, can be sown outside now. Start removing side shoots from the leaf axils of cordon tomatoes.