Project Overview

In the early 2000s, Rockwall, Texas, launched an ambitious initiative to reinvigorate its historic downtown district. Improving accessibility and pedestrian connections was a priority, along with updating aging streets, sidewalks, utilities, and other infrastructure. The 100 block of San Jacinto Street — previously a short one-way roadway containing 25 angled parking spaces — was identified as an opportunity to create something entirely different: a central gathering place connecting the surrounding businesses and public spaces.

The resulting San Jacinto Plaza is a red-brick pedestrian space with a small stage, movable tables and chairs, lighting, seat walls, and direct connections to nearby shops and restaurants. Seven new trees were planted with support from the DeepRoot Silva Cell system, installed beneath the plaza in 2014 to provide quality soil while supporting the pavement and accommodating necessary utilities. More than a decade later, the healthy trees and expanding canopies are helping define a vibrant public space that continues to welcome everyday visitors, outdoor dining, and community events.

Take a visual tour of the project by watching the video above.

Shade: A Placemaking Catalyst

A plaza can be attractively paved, furnished, and accessible — but if it’s completely exposed to the Texas sun, people have much less reason to remain there. Shade is often what turns an open paved area into a place where people can comfortably walk, sit, dine, shop, or spend time with neighbors.

That makes shade more than an aesthetic amenity. In hot climates, it can reduce direct solar exposure, make walking and gathering safer during periods of extreme heat, and increase the usefulness of nearly every other element within a public space. Tables become places to linger. Storefronts become more inviting. A pedestrian connection becomes a destination in its own right.

San Jacinto Plaza demonstrates that relationship clearly. Its trees now help soften the extensive brick hardscape, provide pedestrian scale, and create comfortable pockets around seating and adjacent businesses. The plaza also remains an active community venue more than a decade after opening, hosting a seasonal live-music series and other public events. The trees provide a living canopy that will continue becoming more valuable as it matures.

Silva Cells: Doing What Tree Pits Can’t

In a traditional urban tree pit, the visible opening in the pavement often represents nearly all the space available to the tree belowground. Roots quickly encounter compacted soil, pavement foundations, utilities, and other inhospitable conditions. The planting area may accommodate a young tree at installation, but it offers few opportunities for that tree to develop the root system needed to support a large, healthy canopy. Silva Cells change that relationship by allowing uncompacted soil volume to extend beneath pavement.

At San Jacinto Plaza, the layout took particular advantage of this possibility. Five of the seven Silva Cell-supported trees were planted along one continuous corridor of soil beneath the south side of the plaza. Instead of functioning as five isolated tree pits, these trees can explore a connected rooting environment extending beneath the pavement. The other two trees were supported by separate Silva Cell areas on the opposite side of the plaza.

The importance of this design lies less in a single per-tree soil volume number than in how the available soil was arranged. Connecting the primary row of trees opened considerably more belowground space for root growth than conventional pits could have provided within the same paved setting. By 2026, the healthy crowns visible above the plaza offered a clear indication that the trees were successfully using the opportunities created belowground.

Designing Around Utilities

The space beneath a downtown plaza is rarely empty. Utilities, conduits, light-pole foundations, drainage infrastructure, and connections serving adjacent buildings all compete for limited underground space. A successful tree strategy must be flexible enough to work around these necessary elements.

The Silva Cell layout at San Jacinto Plaza was coordinated with the plaza’s utilities and lighting infrastructure. A utility conduit was routed through the open structure of the system; likewise, individual Silva Cell groups were arranged around light fixtures and other obstructions. Because the layout can be adjusted to fit surrounding conditions, underground infrastructure did not require the project team to eliminate the tree soil or reduce the trees to conventional isolated pits.

The system also provides structural support for the brick paving above, including areas that must occasionally accommodate delivery, maintenance, utility, or event vehicles. San Jacinto Plaza did not have to choose between healthy trees, necessary infrastructure, and a durable public space. Its belowground design allowed all three to occupy — and contribute to — the same downtown environment.