I am in the middle of a garden landscaping project, doing most of the work myself.
The design is for a row of pleached beach trees along the north boundary of the property to provide some privacy from overlooking properties. Something like these. See the attached design. The trees at the east end are to run in a bed 65cm wide between the boundary fence and the patio.
Just behind the boundary fence is a single skin retaining wall that starts at the soil level in my property at the patio end and gradually increases in height to accommodate a slopped path down to the adjacent property which is accessed from the rear.
In contrast on my side of the property, the soil level slopes much more gradually (around 1 in 200) from east to west, terminating in a double skin retaining wall 80cm wide, beyond that is an access path and then the property. See photo.
The topsoil in the bed at the patio end is only 20cm deep. Below that is a shelf of limestone, see photo. Two previous trees growing in this area were blown over in high winds. Their roots were not able to penetrate below the rock. Underneath the rock is sandy subsoil.
Just beyond the bed running under the patio is a service trench running east west containing PVC drainage pipe, mains, garden irrigation water pipes and SWA electricity cables that runs down to the property.
I have three related issues surrounding this project which I would value the advice of the forum:
Ensuring the beach trees have sufficient depth of soil to thrive.
The risk of their roots raising the adjoining patio and path surface
How close to the retaining wall and property can I plant the row of trees.
To address 1. and 2. I have already dug down the width of the bed through the limestone to subsoil, starting at the east end and am now beyond the patio. See photo. I am proposing to install a 60cm deep Reroot barrier (already on order), bringing it up so it is level with the sand/cement render that the flags are laid on and 5cm in from the edge of the patio i.e finishing under the patio rather than in the bed. I will backfill with topsoil.
The Reroot comes in 10m rolls and so I have continued digging the trench beyond the patio to provide protection for the path. However as I move beyond the patio, the depth of subsoil increases dramatically and rather than encountering a compacted layer of limestone, I am finding larger limestone boulders within the subsoil.
Therefore my questions to the forum at this stage of the project are:
How far would you advise I keep going with the Reroot barrier to provide protection for the paved surfaces? If I use all 10m, this would take me to within 2.5m of the property wall.
How close to the house would you advise I plant the pleached beach trees given the retaining wall etc? The general advice I have received is to keep trees 5m from the property wall.
If I do plant all the way up to the retaining wall, would you advise running the Reroot barrier right to the end or can I stop once I am beyond proximity to the path? If no, I have enough Reroot. If yes, I either need to order more (possible as order just gone in) or place a ring of Reroot around each tree at the west end of the bed.
How far apart does one usually plant pleached trees? I am working on around 120cm between each tree given the frame is 120cm wide.
Any further advice on the overall planting plan.
Many thanks for your advice. Given I could be making a considerable investment in the trees, I want to ensure they have the best chance of thriving while also not damaging paved surfaces and the property.
Angus
OGD AC DIM 001 Rev A.pdf