The Science of Healthy Roots

Daynan Lepore-Foster (student researcher), Mary Jane Clark (research lead), Craig Willett (A.M.A. Horticulture), Melissa Drake (student researcher), Rain Avila (student researcher), Jason Henry (Vineland Research), Rick Bradt (A.M.A. Horticulture)

UPDATE: June 25, 2020:

This project so far has demonstrated that significantly reducing root defects in containerized tree production is achievable through better propagation methods and transplanting to a container that allows tree roots to continue air pruning prior to final sale. Laterally developed roots reduce tree die-off and improve the changes for tree establishment and long life. With trees becoming valued assets to communities, the importance of long living trees increases.

Costs attributed to replacing trees dying within a few years of planting are significant. It is more cost effective to start with a higher quality tree that establishes and thrives quickly. The right growing container is key to this. A.M.A. Horticulture developed RootSmart™ in partnership with the Vineland Research and Innovation Centre to improve tree propagation quality. This project proves that technology and moves it to the next stage. A.M.A. sells these products across North America and RootSmart™ is slowly going across the world (New Zealand and France so far). Improved tree quality with the right growing containers is needed in our industry. This is a slow-to-change industry and it’s anticipated three to five more years for significant take up of RootSmart™ and the growing container(s) that were chosen to bring to market as a result of this research. It’s still early on the growing container part, as trees take time to grow.

Healthy root systems are critical for long-term health and survival of trees.

When root complications occur, such as root girdling, the lifespan of trees is reduced. Girdling is when, instead of growing laterally into the surrounding soil, the roots grow in a circle, which eventually chokes the trunk, killing the tree over time.

Research has shown that root defects (i.e., girdling) usually start during propagation, when roots come into contact with the walls of a growing container or tray, rerouting growth in an unnatural direction. Once root growth direction is set, a root does not reposition itself as a tree matures. These root defects, especially girdling roots, may not be obvious until many years later when it’s too late to save the tree.

Enter RootSmart™ a propagation system, developed in partnership between A.M.A. Horticulture Inc. and Vineland Research and Innovation Centre, which prevents girdling in the first vital stages of root growth. As a wall-less, bottomless tray, RootSmart™ is uniquely designed to encourage lateral root growth without obstruction from the container.

Niagara College Horticulture students have conducted the first phase of on-campus research trials using the RootSmart™ propagation tray system to help grow healthier white oak seedlings, under the guidance of Mary Jane Clark, Horticulture professor and faculty research lead working with the Agriculture & Environmental Technologies Innovation Centre at Research & Innovation.

Oak trees in particular have unique deep-growing tap root systems and can be challenging to propagate, says Clark, due to root defects developing during early growth as roots come into contact with the propagation tray’s walls. After propagation, preventing root defects continues to be important when growing a healthy oak tree.

In collaboration with A.M.A. Horticulture, Inc. and the Chautauqua community in Niagara-on-the-Lake, NC Horticulture students are investing into a long-term research project to study propagation and production methods throughout the five years while each generation of oaks is growing at the College.

“During propagation in the RootSmart™ trays, we tested three watering methods and two application rates of a controlled-release fertilizer product,” explains Clark. “Currently, we are testing three container types and two Osmocote® controlled-release fertilizers during the first outdoor growing season. The goal is to efficiently grow healthy root systems for the oak trees until they are ready to be transplanted back into the Chautauqua community in Niagara-on-the-Lake as an urban reforestation project.”

Earlier this year NC Horticulture student Daynan Lepore-Foster shared the research team’s findings at the 2019 Landscape Ontario Nursery Growers Short Course. 



 “At A.M.A., we are proud to deliver innovative solutions to our customers. But if we want to continue driving innovation in our industry, we have to make sure we’re connecting with the next generation of growers,” says Rick Bradt, Managing Director of A.M.A. “Their enthusiasm and vision for our industry is inspiring, and we are excited to see what horticulture will look like in the next five to ten years.”