Landscaping/Creating Privacy in Clay Soil

(Question)

I live in a 10 year old subdivision 90 min N- E of Toronto. (50 km North of Lake Ontario).  The back yard faces the West and is approx 60′ wide X 30′ deep. (width goes along back of house which has a concrete patio and walk out basement.)
I would like advice on how to develop some privacy/screen along the fence lines.  Back of yard and one side have a “wood good neighbour style fence ” with third side only a chain link fence. I miss having my trees, shade and lush lawn and want to somehow make a tranquil setting once again.  I also want minimal upkeep if at all possible as i am reaching retirement years.  The soil is so heavy with clay that water pools on top.  I have worked pretty hard to recondition the soil and lawn and now want to know how to make that special yard with the drainage and soils I currently have.  So I feel I need to start with the borders and work inwards.  Please suggest fast height growing shrubs, trees, evergreens that will help me.  Thanks so much and i am really looking forward to hearing from you!

(Answer)

You have pointed out that your yard is comprised of poor-draining, heavy clay soil, which is essentially the limiting factor when considering which trees and shrubs will do well in your yard.  No matter how fast the tree grows, if it doesn’t thrive in heavy clay soil, it is probably not a great choice for your site.  There are many varieties that will grow well in clay soils, including species of maple (Acer spp.), oak (Quercus spp.), dogwood (Cornus spp.), and elderberry (Sambucus spp.), to name just a few.  Since you are aiming for minimal upkeep, I would recommend trees and shrubs that can be allowed to grow freely versus hedges that require regular pruning/trimming/shaping.  To achieve a more immediate privacy effect, choose more mature specimens that will add instant height and coverage.

Keep in mind that certain species of trees and shrubs prefer acidic soils, so it is a good idea to have your soil pH tested.  This link to another post by Toronto Master Gardeners provides information on soil testing in Ontario.

When planting trees and shrubs in poor draining soil, it is a good idea to plant “proud” – i.e. plant so that the top of rootball is slightly higher than the surrounding earth.  This will allow water to drain AWAY from the tree and will help to minimize standing water around the trunk.

Once you have identified the trees and shrubs that will occupy the perimeter of your yard, you can start adding shorter understory shrubs and herbaceous perennials to fill in gaps and create a more continuous effect.  This document by the Missouri Botanical Garden provides information and plant lists for creating a woodland/shade garden.

Some additional links that may be helpful:
ProblemSolver Plants for Clay Soil – Trees (Missouri Botanical Garden)
Choosing the Right Tree (City of Peterborough)