"Working with James was great from the beginning. He put my mind at ease with his product knowledge and his creative designs."
Pools & Retreats · Markham, GTA
Pool Landscaping in Markham.
Astonia Landscaping designs and builds high-end residential landscapes and natural-stone masonry in Markham. Owner James Dennison is a third-generation stonemason, and Astonia has been doing this work since 1975. Every Markham project is owner-led, built by our own WSIB-covered crews with our own equipment, and backed by $5 million in liability insurance. We are a Unilock Authorized Contractor.
- Since 1975
- 3 Generations
- $5M Insured
- WSIB Covered
- Unilock Authorized
In Markham
Landscaping that belongs in Markham.
Markham holds two very different kinds of property under one municipality, and a stone landscape has to answer to both. In Unionville and along the older heritage streets near Main Street, you have established homes on mature lots where the architecture and the streetscape already have a settled character — work here calls for restraint, natural stone that reads as if it has always been there, and detailing that respects the age of the house rather than competing with it. In the executive enclaves of Cachet and Angus Glen, the homes are larger and newer, the frontages more generous, and the expectation is a designed, cohesive landscape that matches the scale of the architecture. We design for the property in front of us, not a template.
Many of these are established executive homes on settled lots, which usually means mature trees, finished grading and existing hardscape that a new build never has to work around. Protecting healthy specimen trees, tying new stonework into established planting, and matching the grade and drainage already in place takes more planning and more care than a blank site — and it is exactly the kind of work that benefits from owning our own equipment and running our own crews, so there are no subcontractor delays and no guesswork on a property where mistakes are visible for decades.
Markham homeowners making a once-in-a-generation investment in their property tend to value the same things we do: craft that lasts, a clean and respectful site, and direct communication with the person responsible for the work. James is on your project and reachable every day. We haul all debris away in our own trucks — no bins parked on the driveway of an established street — and we leave the site tidy each evening, because in a settled neighbourhood the condition of the site matters as much as the finished result.
What we build
Pool Landscaping, start to finish.
Pool Surrounds
Coping & Decking
Poolside Lounges
Cabanas & Pavilions
Privacy Planting
Stone Walls & Steps
The craft
Built from the ground down.
A pool is the easy part. What makes a backyard feel like a retreat is everything that surrounds it — the coping your feet meet stepping out of the water, the deck that stays cool and sure underfoot, the planting that closes the space off from the neighbours and the road. Astonia builds that whole surround. We work alongside your pool builder, or come in once the shell is set, and design the masonry and landscape that turn an installed pool into a place you actually want to spend the summer.
The stonework is where five decades of masonry show. Coping is cut and set so the edge is comfortable to sit on, true along its run, and pitched to shed water away from the pool rather than back into it. We lay the surrounding deck — natural flagstone, large-format porcelain, or Unilock paving as the design calls for — over a properly built base so it sits flat and drains for the long term, not just the first season. Around a pool the small things matter most: slip underfoot, the transition from wet coping to dry deck, joints that hold against freeze and thaw. As a Unilock Authorized Contractor and a third-generation stone family, we hold those details to the standard the rest of the property is built to.
Beyond the water's edge we build the rest of the retreat — a sunken lounge or fire area set into the grade, a shaded cabana or pavilion for changing and shelter from the afternoon sun, low stone walls and steps that organise the levels, and the privacy planting that makes a backyard feel enclosed without feeling walled in. Layered evergreens, ornamental trees and perennial beds are chosen for your soil, sun and exposure, so the screen fills in and the planting reads as established rather than newly dropped. The result is a pool you arrive at through a designed landscape, not a rectangle of water on a bare lot.
Pool projects are disruptive by nature, so how the work is run matters as much as how it's built. Astonia is owner-led — James is on site and reachable day to day, not a name on a contract. We run our own small and heavy equipment, so excavation, grading and stone setting move on our schedule rather than waiting on a subcontractor's. Every load of spoil and debris leaves in our own trucks; there is no bin sitting on your driveway for the season. Crews are WSIB-covered and the company carries $5M in liability insurance, so a major project on your property is handled the way it should be. We've built outdoor spaces across the GTA and Durham region since 1975, and a pool retreat is one of the most rewarding things we do.
How it works
From first handshake to final reveal.
01
Initial Consultation
We meet you on-site to walk the space, understand how you want to live in it, and talk through your vision and investment — no obligation.
02
Design & 3D Review
Our designer measures and plans your space, then renders it in 3D so you can see it before we break ground. We refine every detail together.
03
Breaking Ground
Our own crews and equipment start at 7:00 AM, keep the site clean every day, and brief you each morning and evening — no subcontractor gaps, no bins.
04
Project Completion
After a final walkthrough, the only thing left behind is your finished space — built to gather on for generations.
The Astonia difference
Why homeowners in Markham choose us.
Owner-led
Daily communication from James, from the first handshake to the final reveal.
Our own equipment
Small and heavy machines, run by our own crews — no subcontractor delays.
No unsightly bins
We haul every bit of debris away in our own trucks, every day.
$5M insured
Liability coverage above the industry average, for your peace of mind.
WSIB covered
A fully covered, professional crew on every project.
Unilock Authorized
Warranty-grade materials and professional installation standards.
Kind Words
Homeowners across the GTA, on the Astonia experience.
Five decades of referrals across the GTA & Durham — and a Unilock Authorized Contractor. Read more on Google & Houzz.
"The natural stone work and landscape job that James and his crew did is beautiful, outstanding work. The quality is outstanding — we would recommend this company to anyone."
"Astonia was a delight from start to finish. The crew showed up early and worked long days to finish on time. We are now enjoying the most amazing front yard. Outstanding results!"
"As a repeat client, we selected Astonia to transform our simple backyard into a relaxing space amongst a natural setting that will bring us many years of pleasure."
Good to know
Pool Landscaping in Markham, answered.
Our craft is the masonry and landscape that surround the pool — coping, decking, lounges, cabanas, walls, steps and privacy planting. We work alongside your pool installer, or step in once the shell and equipment are in, and build the retreat the pool sits within. If you're starting from a bare yard, we coordinate the surround and full landscape so it all reads as one design rather than separate trades.
We work to avoid that. Because we own our excavation and grading equipment and haul every load of spoil and debris away in our own trucks, there's no bin parked on your driveway for weeks and no waiting on outside crews to clear the site. James runs the project directly and keeps you informed day to day, so you know what's happening on your property and when the space will be ready to use.
We design and build across the GTA & Durham region — including Toronto, Etobicoke, Mississauga, Brampton, Oakville, Vaughan, Markham, Newmarket, Aurora, King City, Whitby, Oshawa, Bowmanville and the surrounding areas.
Every project is different — from focused stonework to a full landscape transformation — so we provide a clear, detailed proposal after an on-site consultation rather than a generic price. Most of our work is a meaningful, lasting investment in your property.
Timelines depend on scope, and you receive a realistic one at the design-review stage before we break ground. Because we own our equipment and run our own crews, we work efficiently — starting at 7:00 AM and keeping the site clean every day.
Yes. We carry $5 million in liability insurance — above the industry average — our crews are fully WSIB covered, and we are a Unilock Authorized Contractor.
More services in Markham
Pool Landscaping nearby
Pool Landscaping in Markham, done right.
Book a free on-site consultation. We design, build and plant the whole space — then haul it all away when the last stone is set.
$5M insured · WSIB-covered crews · 3rd-generation craftsmanship since 1975