New Annuals in the Landscape
Observations from the 2022 Guelph Trials
April 27, 2023 By Rodger Tschanz
In the University of Guelph trials, annuals are tested in both containers and under landscape conditions in multiple locations within an hour’s drive of the University of Guelph. While not perfect, this multi-site testing process can help us picture how different cultivars perform under different growing conditions in southern Ontario. It’s interesting to note that greenhouse and container performance isn’t necessarily reflected in landscape performance. Sometimes we even notice differences in landscape performance between different colours within a series. The selection of plants highlighted in this article demonstrated excellent performance in both containers and the landscape under our trialling regime.
Dragon Wing White F1 (1) from PanAmerican Seed is the new colour in the series to now accompany the ever popular red and pink colours. This selection performed well in the landscape spreading up to 76 cm and reaching heights of 50 cm. From our observations it appears to be slightly more vigorous than the red colour.
The Hula F1 (2) series is available in four colours: Bicolour (Red White), Blush, Pink, and Red. In our trials, all colours in the series reached heights of 25 to 30 cm with landscape spreads ranging from 54 cm for Red and up to 80 cm for the Blush. This is another begonia form PanAmerican’s begonia program.
Canna (3) Cannova Red Golden Flame, from American Takii’s breeding program, is available from Ball Ingenuity. This seed-propagated selection has green foliage and a unique bicoloured flower: scarlet red bloom edged in golden yellow. Great landscape and container performance. Compared to other seed cannas in this series, Red Golden Flame was 20 to 30 cm shorter with height reaching 106 cm and a spread of 84 cm.
Coleus (4) Coleus Main Street Shibuya Street from Dümmen Orange stood out this year. Beautiful upright habit reaching heights of 73 cm by summer’s end. No visible bloom was observed before frost ended the trial.
Coleus ColorBlaze Mini Me Watermelon (5) From Proven Winners, this cultivar has a compact growth habit, small leaves, and brilliant reddish colour and narrow green and yellow margins. It did produce small quantities of bloom late in the season, but foliage colour continued to dominate the visual show. Got to love this fun great marketing name as well!
I trialled the first colour in the Supertunia Mini Vista (6) series just before the onset of the COVID-19 pandemic. Proven Winners has released new colours every year since with Red, Yellow and Midnight (dark purple) being trialled in 2022. This series is typified by vigorous spreading (80 to 90 cm) and mounding growth (height of 30 to 49 cm), small bloom diameter (up to 3.5 to 4 cm) and a reliable bloom habit.
It has been a long time since I trialled a petunia that was selected for its large bloom diameter. If anything, in recent years there has been a trend amongst breeders to develop smaller diameter blooms. With bloom diameter of up to 8 cm, this Sanguna Mega series is breaking that trend. 2022 wasn’t a great summer for testing rain response amongst petunias since we rarely had rain, but Sanguna Mega Pink Vein and Mega Purple Vein (7) blossoms rebounded well from the rain we did have. This petunia also has reasonable late season tolerance allowing it to bloom into late October. Garden height of 27 to 35 cm and spread of 74 to 84 cm.
The Smartunia Windmill (8) from Dummen Orange is the first Tobacco Mosaic Virus resistant petunia series to be released to the market. Of the series, Windmill Hot Pink had the best landscape performance in our trials.
Of the six colours in the new SureShot series of petunia from Ball, I was most impressed with the landscape performance of Blueberries & Cream, Dark Red (9) and White. These cultivars bloomed consistently throughout the summer and well into October. Growth in the landscape saw these colours reaching heights of 27 to 38 cm with a spread of 67 to 83 cm; bloom diameter reached 5.3 cm. The dark red and white colours would suit Canada Day planting applications very well.
The Ball Horticultural company has released two exceptional impatiens series for the landscape and containers.
The Glimmer series from Ball FloraPlant has a double flower and is highly resistant to Impatiens Downy Mildew (IDM). It is available in seven colours: white, appleblossom, bright red, dark red, burgundy, hot pink (10) and salmon. In the landscape heights ranged from 27 to 35 cm with a spread of 59 to 72 cm. Flower diameter reached 5.5 to 6.5 cm depending upon the colour. These plants were grown in beds that had experienced severe IDM infections in past years and showed no IDM symptoms at any point throughout the 2022 season.
Solarscape (11) is a new seed propagated New Guinea-like interspecific impatiens from PanAmerican Seed that is truly sun tolerant. In the landscape, this series did very well with heights at the Royal Botanical Gardens (RBG) trial site reaching 22 cm with a spread of 32 cm for most of the colours. Salmon Glow XL (12) reached a height of 28 cm and a spread of 42 cm. It is resistant to IDM as well.
Cyperus ‘Queen Tut’ (13) is a new member of Proven Winners’ “Graceful Grasses” collection. Botanically, it’s not a grass but a sedge and is a close relative to papyrus. As such, it can grow well under waterlogged soil conditions, but our experiences show it can grow just as well in our main trial beds and containers. Compared to other members of this collection such as ‘King Tut’, ‘Prince Tut’ and ‘Baby Tut’, this selection has a finer texture and more compact growth habit. Queen Tut reached a height of 59 cm and a spread of 60 cm at the RBG trial site by October.
Muehlenbeckia complexa. Proven Accents ‘Big Leaf’ (14), commonly called big leaved wire vine, caught my attention in 2022. It works well as a “spiller” and background for showy floral components in a mixed container. In the landscape it creates a spreading monochromatic ground cover. The leaves are mostly round with diameters reaching 3.5 cm. Its bloom isn’t spectacular but since you are growing this selection primarily for its foliage and habit, that’s not a problem. It is able to survive light frosts without a problem but is not as cold tolerant as is, for example, petunias foliage.
The licorice plant selections Helichrysum stoechas, Sylvita Patio (15) and Sylvita Basket from Benary Plus have excellent cold tolerance. Sylvita Basket has more of a trailing habit and while Sylvita Patio is more upright with denser foliage. The narrow, silver coloured foliage provided a great background in the garden for plants such as the blue mealycup sage. It has great late season performance brightening up dark garden areas in the late fall and early winter.
Late Season Bloomers
The large number of bidens in the trial this year impressed upon me the value these plants have in adding late season colour to containers and the landscape. When many of the summer annuals have perished, bidens are still blooming. In addition to being a great choice for autumn-themed plantings, bidens provide pollinators with late season food. Some of my favourites for flower density this fall included the Brazen Samurai (16) and Eternal Flame from Syngenta Flowers and Namid Compact Yellow 23 from Selecta One.
The vegetatively propagated calendula Caleo Orange (17) from Syngenta Flowers is another cold tolerant bloomer that only stops blooming when confronted with extreme cold. During the summer this selection bloomed extremely well in the heat and was resistant to powdery mildew. Height: 34 cm. Spread: 76 cm.
Lobularia or sweet alyssum is known for its cold tolerance. Although I had only one lobularia entry in the 2022 trial, Stream Violet (18) from Danziger, stood out for its reliable all-season bloom and vibrant colour. This vegetatively propagated selection continued to draw attention late October.
AmeriSeed is an Asian plant breeder known for its large-flowered marigold releases – i.e., the Big Duck series. We trialled orange and yellow colours of a new landscape type from this company with a series name of Hedge-Mary (19). As the name suggests it produced a nice bushy plant (61 cm in height by 80 cm spread) with showy large (up to 10 cm diameter) flowers.
The interspecific Zydeco (20) series of zinnia from Syngenta Flowers has one of the largest bloom diameters (bloom diameter of 7 to 9 cm) in its class of powdery mildew resistant double zinnias. The 2022 growing season climate promoted powdery mildew infections on susceptible cultivar. The three Zydeco colours in the trial – Cherry, Deep Yellow and White – all remained PM free. This series was showy and a reliable bloomer throughout the summer. Plant heights of 47 cm were reached with spread of 60 to 74 cm.
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