The landscaping technique of pleaching trees originated in French and Italian gardens in the 16th century at the time of the Renaissance. To pleach trees means to plant them in a row with the branches of one tree intertwined with those of another standing next to it, forming a narrow hedge. Although not all trees have a structure favourable to pleaching, the lime tree has been typically used for that purpose. Plant a row of trees where the soil drains quickly.
Dig planting holes next to each other 4 feet apart. Make them slightly shallower than the trees' root balls are long, so the graft union of each tree is above the soil line. The root crowns will be positioned just above the surface. Don't amend the ground with fertiliser or organic matter.
Slide the trees out of their nursery containers and plant them one at a time. Hose some of the growing medium clinging to the root balls off to expose 1 inch of the root tips. Place the lime trees in the centre of the holes and back fill them with topsoil halfway to the top. Water the tree and wait for the soil to settle. Finish refilling the hole and irrigate each tree to the root zone. Cover the exposed top of the root ball with 1 inch of soil to prevent it from drying. Follow the recommended steps for caring for lime trees.
Insert a tree stake next to each lime tree. Tie the trunks to the stakes with rope.
Interlace one tree's lateral branches with the branches of the one standing next to it. Tie the braiding with twine. Perform this task during the growing season, as new wood is still flexible.
Prune branches back to one bud from the trunk if they are positioned in a way that's impossible to braid them laterally. Do this step in the fall or winter. Pinch new growth in the first growing season to promote branch development, creating a foliage-dense hedge.
Remove the stakes and twine once the lime trees become established. Trim new growth back every summer to maintain the trees' pleached structure.
Install trellises behind young lime trees and tie the braided branches to them for training. The frame is particularly helpful for training the end branches on either side of the hedge. After the wood ages and becomes stiff in place, you have the option of removing the support.