Trees Please Hamilton

Green Solutions to Air Pollution

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How to Build a Rain Garden 101

Last Tuesday’s workshop focused on building rain gardens at home, through the expertise of Michael Albanese of AVESI Storm Water Management Solutions.  While we love rain gardens for the stormwater management and beautiful plants, Michael’s most important priority with the construction of rain gardens is to keep the people and properties safe from water damage.

There are three main approaches to rain garden design:

  1. Excavate and replace: excavate all soil at least one metre deep, replace with a pre-made mixture of sand, compost, and top soil. No tilling of the subsoil.
  2. Dig and shape: excavate to desired depth, no outside soil added, shape rain garden
  3. Excavate and amend: Michael’s preferred approach, in which one excavates to the desired depth, till the subsoil, mix in compost, and shape rain garden.

Before you begin, identify the existing grading and drainage of the property, and how the house was designed. Mark out all downspouts, and assess how to redirect them to take advantage of the natural gradient of the property.  Be aware if you notice water pooling somewhere on your property: this indicates poor drainage, and it would be better to put the garden slightly upstream of this point to help it drain a bit before reaching that spot.  Keep the garden about 3 metres from the foundation of the house. Be sure to call Ontario One Call before digging.


As you begin designing, consider the following:

  • How big is the contributing area?  Your garden footprint should be about 10-20% of this size.
  • How big and deep should the garden be? Ponding depth should be between 2-8″, with soil amendments around 6-12″ deep. Your rain garden can be any shape or size that works for your property – there are no set rules.
  • How is water getting in and out?
  • Is the area in sun or shade? What species should you choose to plant?
  • What are the properties of the native soil? How should this be amended?

As much of the soil in Hamilton is dense clay, you need to dig out some of this layer and remediate with a mixture of other soils.  If you dig too deep to replace clay, you create a “bathtub effect”, where a large quantity of water fills up without an overflow drain, and plants sit soaking for longer than 24 hours.  Amend the soil by tilling, adding compost and garden soil.  Choose native, water-tolerant plants with deep roots to help maintain the rain garden over time.  Native wildflowers beloved by pollinators (ex: asters, coneflower, black-eyed Susan, goldenrod, etc.) will have your garden working double duty.  Make sure each plant has room to grow, and avoid species that will drastically outcompete the others.  Top with a shredded mulch (not chipped) 2-4″ deep.


Photo: Michael Albanese

You can slow down water as it makes its way to your rain garden by adding river rock with some liner underneath to help infiltration. You may want to redirect using a rain barrel, with the overflow hose leading to the rain garden.  Take proper care of your rain barrel. Make sure there is a spigot on the bottom high enough off the ground so you can fit your watering can underneath, some sort of overflow management on top, and a filter at the downspout entry.  Always drain the barrel before the next rain to ensure full capacity, and make sure to direct the overflow downhill and away from the house.  Empty and seal your barrel before winter, or just turn it over to protect from damage.

When designing your rain management system, take the “Treatment Train” approach to combine features to handle more rain.  For example, connect your downspout to a rain barrel, which drains into a bioswale, flowing into a rain garden.


Photo: Michael Albanese

Michael’s main message from the evening: it’s easier than you think!  There are many resources out there to help you along the way.  Give it a try and get digging!


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Buying a house to save a tree


Photo: Carlos Osorio, The Toronto Star

Can the city crowdfund the purchase of an old bungalow to save the 350 year old Red Oak threatening the foundation?

If the city isn’t interested in paying the property value of around $750,000 plus the additional “opportunity cost” the tree is imposing on the structure of around $60,000 – $80,000, then the current homeowners will need to cut down the tree to attain the full value of the sale.

This heritage tree would require city council approval before it could be cut down, which would likely be rejected according to a city spokesperson.  Apparently the city has previously attempted to purchase this property, but at the time the homeowners were not selling.

We look forward to seeing what the City of Toronto does with this tree.  Can this case set a precedent for city purchases of residential property to conserve nature?

Read the full Toronto Star article here.

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Rain Gardens and Storm Water Management Forum

The Restoring Resilient Spaces workshop series kicked off last Tuesday evening at the Perkins Centre with a Rain Gardens and Storm Water Management Forum.  Our guest speakers hailed from Credit Valley Conservation, the City of Hamilton, and Green Venture, the Bay Area Restoration Council, and the Hamilton Conservation Authority all attended the event to share their knowledge and ongoing projects.

With the expectation of more extreme weather events into the future and an aging infrastructure system, the time is now to restore resilient green spaces in our cities.  More intense “100 year” storms will lead to greater flooding and more rapid erosion in systems that were not designed for these major and frequent events.  The results can be costly, both municipally and personally.


Flooding on the Red Hill in 2009. Photo: Lynda Lukasik

Melanie Kramer introduced the topic of Green Infrastructure (or rainscaping, bluescaping, Low Impact Developments, etc.) with a simple goal for rain water: slow it down, soak it up, and keep it clean.  By changing the traditional storm water management techniques, we can treat rain where it falls, along the path, and before it reaches the waterway.  This begins with spreading the knowledge that storm drains go directly to the lake, untreated, picking up contaminants along the way.  During a major rain event in Hamilton, this issue is compounded with the old combined sewer overflow system, meaning raw sewage is occasionally spilling out into the harbour.

Slowing down the water reduces the opportunity for flash floods. Water collects and flows quickly on the impermeable surfaces that cover the city, picking up contaminants along the way.  By reducing the amount of impermeable surfaces and replacing pavement with permeable material, rain gardens, and other green infrastructure, more water will be absorbed by the system before it pools and floods.  Constructing green roofs or disconnecting your downspout and redirecting it into a rain barrel, or to flow into a rain garden removes it from directly flowing into the storm drain.

Rain is processed and filtered naturally by soaking it up in a rain garden.  Low Impact Developments like these filter, store, and return rainwater to the ground, mimicking nature in a cost effective way, and reducing the stress on traditional storm water infrastructures.  Throughout the city, boulevard plantings could be vastly improved through smart design: curb cuts to allow water to flow in from the street, permeable sandy soils, water-loving plants and trees, all cleverly arranged to capture, hold, and filter rainwater before it can flood.  These projects can also add beauty, interest, amenity space, and education opportunities in the community.  Soak away projects used trenches of gravel lined with fabric to help collect water in an attractive garden feature, or can be designed with topsoil and grass for a hidden feature that will deal with ponding in a low maintenance way.

Winston Wang enlightened us about what Low Impact Development practices have already been constructed in the City of Hamilton, and what is underway.  See the full list here, and a fantastic website by the Toronto and Region Conservation Authority here that tracks projects around the province.  These projects include infiltration trenches to reduce ponding in alleyways, infiltration trails in parks with flooding issues, soak away pits with curb cutaways along the roads, rain harvesting barrels at Limeridge Mall, green roof at City Hall, depave projects and garden planting to improve permeability, and beautification of traffic calming bump outs by creating bioswales to capture and drain rainwater.  In new developments in the City, downspouts are no longer allowed to be attached directly to the storm drain, and the City promotes Proactive Plumbing, through downspout disconnection and storm water management.  The lesson learned here: talk to your councillor to let them know that these projects are important to you and worth the investment for the future.


Adele Pierre wrapped up the evening by combining the two former presentations into a vision for the future in Hamilton: the use of green infrastructure to beautify and better the beloved Ottawa Street.  While the community adores this street, it is notably lacking in green space.  There is so much impermeable surface and nowhere for water to go. Projects have already successfully reimagined the streets of Brooklyn and Portland as beautiful and functional storm water management systems.  The sidewalks on Ottawa Street are large – wide enough to accommodate bioswales and allow generous space for pedestrians, while adding amenities like benches under a richer tree canopy.  Adele invisions permeable pavement, with soak away systems underneath.  Curb cut outs and grates bring water from the street to bioswales, in which native plants and sandy soil soak up rain water.  Traffic calming curb bump outs would be filled with these bioswale gardens and healthy trees that have ample soil to grow.  The similar road installations in Portland and Brooklyn have been shown to manage almost all of the runoff from a 25 mm storm event.  The existing parking lots in the area produce over 1,000 m3 of runoff in a 25 mm storm that carries oil, grease, and other contaminants right to the harbour.  By using permeable pavement in the parking spots and adding bioswales down the centre, 95% of runoff is absorbed into the ground, and 99% of the oil, grease, heavy metals and other pollutants are held in the soil.  Her incredible and visual Master’s thesis is online here.


From Adele Pierre’s Master’s thesis

Presently, the Hamilton Conservation Authority has grants available to help create rain gardens in Ward 1 and Waterdown.  Learn more about the need for a fair storm water fee  in Hamilton and let your councillor know that this is important for our city.

Be sure to attend our “How to Build a Rain Garden 101” workshop on Tuesday, April 10 from 7pm-9pm at the Perkins Centre (register at to learn how to transform your own yard!

UPDATED Restoring Resilient In Urban Green Spaces

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Trees for storm water management

Our workshop series kicks off tonight with the Rain Garden and Other Green Infrastructure forum! We look forward to hearing from local experts about what is currently going on in this field in Hamilton.


To get us ready, here is one of the many reasons we want to see more trees planted throughout Hamilton: storm water management.

Hamilton’s old combined sewer overflow system is a well-known issue that looms with every large rain event. Trees help control water run-off, helping to avoid the flooded roads we often see during a big spring storm.  Rather than a barren stretch of pavement dotted with overflowing drains, leaves intercept the rain drops, and roots thirstily drink up as much as they can.  Tree roots also stabilize the soil and keep silt away from polluting our streams.

By lining our streets with trees and other vegetation, pressure can be relieved from a stressed storm water system. Imagine a well-planned street with healthy and hardy native trees, with gardens of plants underneath available to pollinators, all quenched by the storm water that needs some place to go. Rectify the area in your lawn that always has poor drainage by putting in a simple rain garden, or even just the one water-loving tree. Explore these beautiful and beneficial solutions to our urban storm water problems at the forum tonight!


Our little office White Pine is not intercepting much rain water yet

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The impact of trees on academic performance

Last week, we attended a pop-up forestry conference at the University of Toronto to participate in some knowledge sharing.  One study just published is particularly relevant to Trees Please in Hamilton, where we have been working in collaboration with schools to plant more trees in school yards.  We know that the busy drop-off and pick-up creates a lot of air pollution so close to the school – usually right where the kindergartners play!  But a new study from the University of Toronto now shows a positive relationship between tree cover in school yards and academic performance.

Tree Cover

This research looked at 387 schools in the Toronto District School Board, inquiring whether tree cover and species diversity has an effect on Grades 3 and 6 EQAO test scores. By controlling for socioeconomic factors, which have the greatest effect on academic performance, the researchers discovered that tree cover has a significant impact.  In fact, this effect was the strongest in schools with the highest external challenges, and the biggest effect was seen in Grade 6 math scores.

As many other studies have shown, green space has important impacts on increasing physical and mental well-being.  A related study found a link between the amount of green space that students can see through school windows and an increase in test scores.  Attention Restoration Theory suggests that “contact with nature restores and redirects one’s attention to the current task at hand”.  Green space can positively impact  overall well-being by decreasing neurophysiological stress.

The researchers used NeighbourWoods data for schoolyard trees – the same protocol upon which Trees Please was based.  Like Trees Please, they looked at species, diameter, height, and overall condition in over 20,000 trees at schools across Toronto.  They found that the most effectual tree species were simply the most common, leading them to believe it doesn’t matter what species are planted, just that there are many.  Even conifers, with their year-round green, did not have an additional impact, however, tree cover had a higher impact than other types of vegetation.

Tree inventory

A gorgeous Silver Maple at the former St. Helen’s School in McQuesten

This research is extremely valuable to convince school boards to invest in trees for academic performance, in addition to the numerous health benefits.  With the more pronounced effect in the schools with the highest external challenges, a small depaving project in the urban core could go a long way.  While current tree budget is very low for many school boards (this paper quotes 0.1%!), this research provides a good incentive to help rationalize investing in trees for school yards.

Last November, we planted seven native trees at Sts. Peter and Paul School, which we hope will grow to help with both air quality and test scores!  We are currently working with other schools for more plantings in 2018.  Let your schools know all the wonderful benefits of trees, and let’s green playgrounds across Hamilton!



Remember to register for our Restoring Resilient Green Spaces series, beginning next Tuesday, March 27!  We look forward to hearing from local experts about what we can all do locally to manage storm water, plant native species, and identify invasives.  Contact Carolyn or Juby at to register today!

UPDATED Restoring Resilient In Urban Green Spaces

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Rain Gardens & Other Green Infrastructure

We are looking forward to the forum kicking off our Restoring Resilient Green Spaces in Hamilton workshop series!  Come learn about the innovative techniques being used in Hamilton to manage storm water into the future, and explore what you can do in your own yard.

Spots are still available for this session next Tuesday, March 27 – we’d love to see you there!  Contact Carolyn or Juby at to register today!


Adele Rain Garden

Rain Garden: Adele Pierre