Perennials in Poor Soil

(Question)

The city did a large scale remediation, dug 10 feet deep and replaced soil with sand topped with 2 inches of soil. They tore out my cedar hedge, a globe cedar, weeping spruce, euonymus, and hydrangeas. My garden is ruined. What or how can I plant now?

 

(Answer)

Thank you for contacting Toronto Master Gardeners with you question.

Wow, that is quite a setback and am sure very disappointing development.

From a pure botanical point of view, to have a healthy garden or landscape, one must focus on the quality of the soil .  It is critical to evaluate what you really have to be able to make the right decisions, both on what you intend to grow, and what actions you need to take to properly amend the soil to the desired state.

First I think I would want to know how different the new sandy subsoil that they put in is from the surrounding native soil?  Specifically, if they have put in sand; what type of sand …… is it pure sand or is it a sandy loam or a mixture.  Does it have any organic matter in it? If your surrounding soil is say clay , then having a sandy disparate soil next to this is a very unhealthy combination for a number of reasons.

The best option from a horticultural standpoint would be to till in a good amount of organic matter, and in so doing try to mix the new soil with surrounding sections so as not to have barriers, or walls of different soil types. This is a high level strategy, but the details of how much or how deep depend on an assessment of different factors.  If you are a DYI er and want to do some soil testing, then please find a reference for accredited soil testing laboratories; http://www.omafra.gov.on.ca/english/crops/resource/soillabs.htm

Guelph University used to have a free service for this.

Your shrubs that have been removed  all have preference for acidic soil, so if you still plan on planting similar shrubs, you may want to conduct a soil test on the new soil to verify PH and even organic matter content.

As you can see this is not a simple answer because there a number of variables here that would help best determine your decisions. If you feel overwhelmed, I would strongly recommend hiring a knowledgeable landscape company who have expertise in soil science.

You might also want to look for plants and shrubs that have a stronger preference for sandy soils.

Rather than naming a few, you will find the following link from Penn State University very comprehensive;

https://extension.psu.edu/trees-shrubs-and-groundcovers-tolerant-of-dry-sites

I hope this gives you some helpful information . and good luck with the recovery project, and a new garden in the making!