Hi I am looking at planting 6 of this along a fence in the backyard aprox 6’ apart. There is a retaining wall 3’ away from the fence and these will be planted between the wall and the fence. There is also a swimming pool 4’ forward from the retaining wall. Was wondering if these have agreed roots that will push the retaining wall and/or damage the pool due to root growth. These also grow 30-40’ tall at maturity and span 25’. They can be pruned to keep them a desired size but was wondering if this tree is right for the area?
Pyramidal European Hornbeams are a beautiful tree and are good for privacy hedging because they keep their dead leaves throughout the winter. These leaves are eventually pushed off when the new leaves grow in the spring. They are somewhat a slow grower, like average to moist soil, are not particular about ph, will grow in full sun to partial shade and are tolerant of urban pollution. Hornbeams have taproots rather than a lot of roots close to the surface. This tendency for their root systems to grown down rather out will serve you well in your situation with the retaining wall close by. I don’t think the roots will harm the swimming pool. From reading I’ve done about foundations and tree roots, tree roots exploit cracks that are already there. Does your pool have cracks?
With regards to how far apart to plant the trees for the purpose of hedging, I got a lot of different opinions:
- 1/2 of the mature spread, which would be 12.5 ‘
- Michael Dirr, a botanist at the University of Georgia who has written many books on his specialty, woody plants, suggests 10 ‘ apart
- a nursery site suggested 3′ apart
If trees are planted too close together, root competition will lead to sub-par performance or even, potentially, death. If trees are planted as far apart as 12-13 ‘, then it will take forever to fill in as a hedge. I think the 6’ apart you suggest is a good compromise. The hedge should be pruned annually from late summer to mid-winter to reduce stress on the tree and to minimize bleeding of the sap.
This link, from the Morton Arboretum, has information on tree root problems:
We receive numerous questions concerning privacy hedges; this link will take you to similar questions which were posted on our website and will give you additional options for you to contemplate.