May 4, 2021
CNLA News May 2021
Black knot can be caused by the fungus Apiosporina morbosa.

New Plant Development Committee takes on black knot

Black knot caused by the fungus Apiosporina morbosa is a common disease of plants in the genus Prunus. The most distinguishing symptom of black knot is the characteristic black, tar-like swellings that develop on branches of the infected plant.

Black knot is the major reason why chokecherries are no longer being sold or planted in the landscape. If they could be bred to be more resistant, it’s quite likely chokecherries would make a comeback. CNLA’s New Plant Development Committee is at the beginning of a new research project that will lay the groundwork for a breeding program for black knot resistant chokecherries.

Research is first needed to develop reliable and repeatable inoculation methods for black knot.  This is where the new research project will start. Dr Bob Bors, a respected ornamentals and small fruits breeder at the University of Saskatchewan will lead the research, with the initial goal of identifying techniques to successfully and repeatedly inoculate trees with black knot and that can be used over much of the growing season or under greenhouse conditions.

Box tree moth update

Landscape Ontario, CNLA, OMAFRA and CFIA successfully completed another season of surveillance for Box Tree Moth in Ontario in 2020, with a heavy focus on the Toronto region. The moth has spread slowly in all directions but remained inside the perimeter around Toronto that was established in 2019.

The Box Tree Moth Industry Working Group has been very active on this file and continues to meet regularly to monitor this invasive pest and its impact on nurseries. Three key areas predominate meeting agendas – surveillance and monitoring, communications to the public and to growers, landscape contractors and garden centres, and protecting trade in boxwood with US customers.

New member saving programs

CNLA is proud to announce a new partnership with Equinox Environmental that will provide members with a 10 per cent MSRP discount and a 2.5 per cent CNLA partnership discount on planters and waste management containers.

CNLA also began a partnership with Parkland Fuels, which delivers gasoline, diesel, propane, lubricants, heating oil and other petroleum products to motorists, businesses, households and wholesale customers in Canada. Email for special custom pricing on fuel.

CNLA Partners with ICPI

CNLA’s Landscape Horticulture Certification Program (LHCP) is partnering with the Interlocking Concrete Pavement (ICPI) so that ICPI certification will now serve as proof of hands-on competence for candidates taking Hardscape Installation (HI) to earn their Certified Landscape Horticulturist Technician (CLHT) designation.

HI candidates who submit their ICPI certificate are not required to provide further proof of hands-on competence. They will, however, still be required to successfully complete the written exams to earn their designation. Additionally, CNLA will collaborate with ICPI to facilitate shipment of ICPI manual orders within Canada. If you already have your ICPI certificate, take advantage of this alliance to earn your CLHT designation.

Reminder to recertify

Members who were due to submit for recertification for 2019-2020 will have until the end of June 2021 to renew, after which a late fee will be charged. For more information on recertification or to find out if you are due to recertify, please contact the CNLA Professional Development team at or 905-875-1399 ext. 8620.

New HR Committee Chair

Green Roof Harold Deenen
Green Roof construction Jeff Foley

Harold Deenen has led the CNLA HR Committee with class, grace and a strong drive to ensure the best for industry, but after many years in leadership he has earned a much-deserved break.  Jeff Foley takes on the chair position, following several years as the chair of the Professional Development Committee. CNLA looks forward to seeing where his vision will lead.