Weekend work: Time to trim hornbeam hedges

What to do

* Trim hedges of Carpinus betulus (hornbeam) this month, treating new hedges gently, cutting harder into established ones. Hedges and screens of Crataegus monogyna (hawthorn) can be dealt with in the same way. If specimen trees of either kind need reducing in size, leave the work until winter when they are dormant.

* Griselinia, a New Zealand native with tough leathery evergreen leaves, is sometimes used to provide shelter in seaside gardens. It is not reliably hardy, though wonderfully resistant to salt and wind. Where it is used to make a hedge it will need clipping, which should be done now. Shrubs planted as specimens need no regular pruning.

* Deutzia, which flowers in June and early July with clusters of small, star-shaped flowers, can be pruned immediately after flowering. The best way is to take out some of the old flowered stems entirely, cutting them down at the base of the plant. This will encourage the production of strong new shoots from the base. It also keeps the shrub within reasonable bounds.

What to see

* IncrEdibles, a summer-long festival at Kew gardens, celebrates some of the world's 12,000 food plants. For a full list of associated events and activities call 020 8332 5655 or go to kew.org. Meanwhile at Birmingham University there's a GIY (Grow It Yourself) gathering next Saturday with a special focus on community gardening. Tickets cost £25. For more details, go to giyinternational.org