Tilia (lime) is the most commonly used tree for pleached walks; usually the red-twigged lime (Tilia platyphyllos ‘Rubra’). Ash, beech, chestnut, hornbeam and plane can also be pleached, as can apples and pears. These can often be obtained ready trained.
Laburnum and wisteria are favoured for pleached arbours and covered walks, especially tunnels, which show off the attractive flowers perfectly. Use wisteria grown from cuttings or raised by grafting, as it will flower more reliably and uniformly than seed-raised plants, and Laburnum x watereri ‘Vossii’ is a better choice than seed-raised L. anagyroides.