Deciduous hedges. Most deciduous shrubs get old over several years time and loose their vigour eventually. Having said that, if your have an overgrown deciduous hedge, it still can be brought back into shape. To begin the process, cut back all growth to about 15-30 cm above the ground just before plants break dormancy in spring, and after any danger of severe frosts has gone. This not only boosts new growth, but also encourages the development of a new root system.
During the rest of the growing season, keep weeding, tilling and watering the soil around the hedge. Fertilise the hedge twice during the season – in early spring, when plants break into new growth (usually, in April) and then again in early summer (late May to early June). The plants will not need any more feeding for the rest of the season. The first year do not clip the shrubs, however, the next spring, cut back new growth on the top and the sides of the shrubs by half so as to encourage a dense habit.
Good shapes for hedge include a flat topped A shape, where the top is slightly narrower than the base, or a gently rounded form. This allows light to get to the bottom of the hedge, which might otherwise become spindly and bare. In early summer, reduce new growth by half or a third, and at the end of summer (but no later than end of August) cut it back once again.
The next year, this process should be repeated 2-4 times (first time in April, and the last one in August). Every cut should be made 2-5 cm above the previous one. This is the most straightforward way to shape the shrubs into a dense and regular hedge. Every year, before you start spring pruning (any time between late autumn to until plants break dormancy) thin out weak or twiggy branches.
Starting with 4th or 6th season, cut out one or two oldest branches yearly to encourage new growth and to keep the bushes ‘young’. However, if the rejuvenated shrubs still refuse to break into new growth, it may mean that the plants are too old, diseased and past any salvation, in which case you should dig out old stumps, replace the soil and plant a new hedge.
© Giedra Bartas, 2011