S14 - Session P4 - Box hedge alternatives: key findings after 8 years of experiment in the south-west of France

Authors: Maxime Guérin *, Caroline Eyssan, Jean-Marc Deogratias, Tabone Elisabeth

Since Andre Le Notre created the art of the « jardin a la Française », box hedges are a key feature of the numerous historic gardens that can be visited all around France. For over ten years now, like everywhere else in Europe, 2 pests destroyed a significant part of the ornamental and natural box trees - the box tree caterpillar ( Cydalima perspectalis ) and the box blight ( Cylindrocladium buxicola ). The control program required such human and material resources that some green space managers no longer want to do it. Instead, they have to remove box hedges and replace them with other kind of shrubs. Since then, nurserymen are proposing many alternatives but none of them meets all the box tree's characteristics (e.g. strong hardiness, low speed of growth). Consequently, green space managers are sometimes disappointed by the evolution of the aspect or the need of maintenance compared to box tree when they choose to plant alternatives at large scale. To help them know what to expect, Astredhor Sud-Ouest-GIE Fleurs et Plantes launched an experiment in 2014 to assess around thirty box hedges alternative taxa (varieties of Ilex, Euonymus, Berberis, Lonicera … ). The bushes were planted in open ground and parameters such as growth dynamic, trimming needs, pest susceptibility and physiological problems were monitored. In addition, the aesthetic value was assessed thanks to a rating scale by a jury of professional gardeners and nurserymen. 8 years of observation allowed us to assess the strenghts and weaknesses for each tested taxa. The next step will be to share this knowledge with green space managers in order to help them decide which varieties suit best their needs. This work was part of the SaveBuxus project - led by Plante & Cite in partnership with INRAe and Astredhor, funded by OFB and VAL'HOR - which goal was to find solutions to control the box tree caterpillar and the box blight.