September 15, 2013
LO and University of Guelph host tours of trial gardens
Those attending the annual trial gardens open house had lots to see, from new annual introductions to perennial beds and roses.
Landscape Ontario and the University of Guelph held consecutive open houses at their trial gardens on Aug. 16 and 17.

For the sixth year in a row, industry members were invited to the LO home office in Milton for a morning of educational presentations, and to see how some of the most recent plant introductions perform in a garden setting.

LO’s executive director Tony DiGiovanni introduced trial gardens manager, Rodger Tschanz of the University of Guelph, noting, “Roger with his quiet passion, is the entire energy behind the success of the gardens.”

Wayne Brown, greenhouse floriculture specialist with OMAF-Vineland, provided an update on the status of impatiens downy mildew (IDM). Impatiens is, or rather, was one of the greatest success stories of the greenhouse sector because strong breeding programs resulted in enhanced garden performance and colour at a reasonable price. IDM has wiped out that success in North America in less than five years.

Regional outbreaks of IDM were reported in the U.S. and Canada in 2011, and now the disease is widespread across the continent. Early symptoms are light green to yellowing or stippling of the leaves and a characteristic downward curling of the infected leaves. Spores will show as a velvety-white growth on the undersides of the leaf. Eventually all the leaves drop off.

Brown explained that initially the symptoms can be misleading as they can look like spider mite damage or a nutritional problem. Downy mildews are all crop-specific water moulds, and IDM affects Impatiens wallerana and interspecific hybrids including Fusion and Fiesta, balsam and jewelweed. New Guinea impatiens has a high tolerance to IDM.

Growers may be able to control IDM during production, but in the landscape there are no products registered that will knock down this disease. Currently, the recommendation is to avoid planting Impatiens wallerana, and chose other shade-tolerant plants including begonia, New Guinea impatiens, browallia, coleus, nemesia, lobelia, fuchsia or ivy geraniums. Brown noted that none of these crops are as cost effective as impatiens and suggested that impatiens breeders are searching for tolerance or resistance to this disease, but we won’t see results from that research quickly.

Growers and retailers can sterilize benches and sales areas with a strong bleach solution, but Brown cautioned that the solution should be rinsed off with clean water after a day or two, to get rid of any chemical residue.

Next, Paul Zammit, director of horticulture at the Toronto Botanical Garden, provided an enthusiastic, entertaining and educational session on container gardening. Zammit illustrated his talk with some great slides, saying containers are an easy way to add colour to the hardscape. He gave some terrific tips and left the audience with a new appreciation of the versatility plants and accessories can offer in container plantings.

Rodger Tschanz led the group outside to the trial beds, and offered information on some highlights of the annual, vegetable, perennial and rose trials. The trial beds at Landscape Ontario are situated in an open field exposed to full sun and sweeping winds, so provide a good test of durability in the landscape. Visitors were invited to continue their observations at the University of Guelph Trial Garden at the Guelph Turfgrass Institute in the afternoon.

The following day, the gardens were opened to the public, where they were invited to tour the gardens, choose their favourite plants and have their gardening questions answered by some of Halton’s Master Gardeners.

The most popular plants chosen by members of the public were: Annual, Superbena Royale Chambray verbena; perennial, Milkshake echinacea; and Campfire rose was the overwhelming favourite among the rose trials. Green industry members touring the trials chose completely differently, Petunia Flash Mob Bluerific tied with Gomphrena Pin Ball Purple for best annual and Echinacea Sombrero Salsa Red was chosen as the industry’s favourite perennial.

Landscape Ontario and the University of Guelph give thanks to the suppliers of the plant material for the trials: All-America Plant Selections, American Takii,  Ball Horticulture, Ball Ingenuity, Blooms of Bressingham, Burpee Home Gardens, Dummen USA, Fides Oro, Genesis Seeds, Goldsmith Seeds, Jelitto Seeds, Johnny’s Selected Seed, Kieft Seeds, PanAmerican Seed, Proven Winners, Sakata Seeds, Selecta North America, Thompson and Morgan, Syngenta Flowers, Van Hemert and Co. Seeds, Vanhof and Blokker, and William Dam Seeds.

Thanks go also, to SunGro, Plant Products, Gro-Bark - Ontario and Myers Industries for support of the trial gardens. Appreciation is extended to the summer students for their help with weeding, as well as the crew members from Boots Landscaping and Maintenance who blitzed the gardens just before the open house. Wayne Brown, of OMAF, helped with the production of the vegetative plants trialled in the gardens.