Landscape design in Old Ottawa South and the Glebe

Inside the Greenbelt the design problem is space and trees, not soil volume. Lots in the Glebe, Old Ottawa South and Old Ottawa East are commonly 7.5 to 12 m wide, with a house occupying most of the width, a back garden of 60 to 120 square metres, and a laneway or a 900 mm side gate as the only access.

That access is the dominant cost driver. Where a machine cannot reach the rear, every cubic metre of excavation and every tonne of base stone moves by barrow, which can add thirty to fifty per cent to the earthworks. Some projects here are done through the house or by crane over the roof, and that has to be decided at the design stage rather than discovered.

The mature tree canopy is the other defining feature and the reason these streets are worth living on. Many of the large trees are City-owned, and the City protects the critical root zone at 10 cm of radius for every 1 cm of trunk diameter, requires protective fencing at least 1.2 m high before work begins, and prohibits placing materials in that zone or changing the ground level around the tree. On a 60 cm maple that root zone is a six metre radius, which on a 9 m lot is most of the front garden.

Design responses that work here are consistent: permeable or open-jointed paving so rain still reaches tree roots, raised beds built without changing the grade around a trunk, shade planting rather than lawn, and vertical screening instead of hedging that needs width. Old foundations are often stone or block rather than poured concrete, so grading and drainage work against the house needs a gentler hand than a 1990s wall would tolerate.