"Working with James was great from the beginning. He put my mind at ease with his product knowledge and his creative designs."

Landscape design & stone masonry in Richmond Hill.
Astonia has been designing and building in natural stone since 1975, and we bring that same owner-led approach to Richmond Hill. James Dennison, a third-generation stonemason, is on site and reachable through every project — so a major investment in your property is handled with daily communication and real accountability, not passed down a chain of subcontractors.
- Since 1975
- 3 Generations
- $5M Insured
- WSIB Covered
- Unilock Authorized
Landscaping that belongs in Richmond Hill.
Much of Richmond Hill's most established character sits in the older, leafy pockets around the Mill Pond and Bayview — deep, settled lots with a mature tree canopy and streetscapes that have earned their privacy over decades. Homeowners here tend to want landscaping that looks like it has always belonged: dry-laid and mortared stonework, planting that respects the existing canopy, and hardscape that settles into the grade rather than fighting it. We work carefully around established root zones and protected trees, and because we haul all our own debris away in our own trucks, your street and your neighbours are spared the bins and the mess through a long build.
South Richvale and the larger estate properties bring a different scale — wide frontages, deep setbacks, and the kind of custom homes that ask for stonework of equal permanence. On lots this size, owning our own small and heavy equipment matters: we move material, excavate, and set stone on our own schedule, without waiting on outside crews or losing weeks to subcontractor handoffs. For a once-in-a-generation project, that control is the difference between a season of disruption and a build that simply progresses.
Richmond Hill also sits on rolling ground near the southern edge of the Oak Ridges Moraine, so grade change is the rule rather than the exception. Many properties here need genuine engineering as much as design — terracing, structural retaining walls, and drainage planned so water moves where it should and the stonework holds for generations. As a Unilock Authorized Contractor, fully WSIB-covered and carrying $5M in liability insurance, we plan that work to be built once and built right.
Five ways we transform Richmond Hill homes.
From first handshake to final reveal.
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.
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.
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.
Project Completion
After a final walkthrough, the only thing left behind is your finished space — built to gather on for generations.
Why homeowners in Richmond Hill 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."
Landscaping in Richmond Hill, answered.
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.
Yes. Our designer visits your home to measure and plan the space, then renders your project in 3D so you can see it before any work begins. We review and refine it together until it is right.
No unsightly bins on your driveway — we haul everything away in our own trucks and leave a tidy site every day.
Astonia is led by James Dennison, a third-generation stonemason with five decades of craft. You get the expertise of a large company with the warmth and accountability of a family business, owner-led from start to finish.
Your Richmond Hill project starts here.
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



