Another Calgary garden

Leucanthemum × superbum Shasta Daisy

“Leucanthemum ×superbum, a reputed hybrid between Leucanthemum lacustre and Leucanthemum maximum, was introduced by Luther Burbank in 1901, and named Shasta daisy for the snowy peaks of Mount Shasta in northern California…Shasta daisy is often considered a short-lived perennial, especially when grown in heavy or wet soils (Hawke 2007)

Shasta Daisies are USDA Zones 5-8 (Hawke 2007) and therefore would not overwinter in Calgary’s Zone 3?

Leucanthemum ×superbum ‘Becky’ was named the 2003 Perennial Plant of the Year by the Perennial Plant Association. “‘Becky’ exhibited a uniform habit with sturdy stems to 40 inches tall and an abundance of 3½-inch flowers from July to September… ‘Becky’ is perhaps the most popular Shasta daisy in the United States today because of its sturdy habit and garden dependability (Hawke 2007).”

Unlike Leucanthemum × superbum, the habit of L. vulgare is rhizomatous (Hawke 2007).”

Leucanthemum vulgare, oxeye daisy, is similar in general appearance to Shasta daisy. The white and yellow flowers are typically smaller, 1 to 3½ inches wide, and bloom up to four weeks earlier. It has smaller green leaves and a rhizomatous habit. Oxeye daisy is readily available to gardeners and frequently confused with Shasta daisy. Both species self-sow in the garden, although oxeye daisy is particularly fruitful (Hawke 2007).”

The plant I originally planted was a Shasta Daisy Leucanthemum × superbum, a popular garden hybrid. Shasta Daisies are sterile so unlike their parent plant, they are not invasive. However, according to the Calgary Garden Coach even Shasta Daisies can revert back to being fertile. It is very difficult to tell a Shasta daisy from an oxeye daisy.

The Alberta Invasive Species Council (AISC) lists oxeye daisy as “Noxious.” Under the Alberta Weed Control Act “Prohibited Noxious” and “noxious” plants must be controlled. According to the AISC Shasta Daisy Leucanthemum × superbum or ox-eye (oxeye) daisy Leucanthemum vulgare “can cross breed, resulting in an invasive hybrid that is extremely difficult to distinguish from either parent. Invasive ornamentals can be very difficult to contain and should be avoided.”

According to Invasive Species Council of British Columbia “Oxeye daisy is often confused with the ornamental Shasta Daisy Chrysanthemum maximum, which has larger yellow disk (2-3 cm) and white ray flowers (2-3 cm).

In July 2015 I began to replace all my daisies just in case. Oxeye are very damaging to crops.

Foliage of Shasta daisies: “Basal leaves are dark green, fleshy, lanceolate with serrated margins, up to 30 cm; stem leaves are shorter, lanceolate and sessile.”

Of course digging them out left gaping spaces in the garden. Gratefully Canadian Tire was discounting most of their perennials so I was able to get a John Davis explorer rose, a Blue Sea Holly Eryngium alpinum, and a Blue False Indigo Baptisia australis to fill the empty spot. A Salvia x. sylvestris ‘May Night’ specimen replaced the daisies in anther bed. ‘May Night’ was named 1997 Perennial Plant of the Year. I will plant another Shasta daisy but I will keep a closer eye on its growth.

References

Hawke, Richard G. 2007. “A Report on Leucanthemum × superbum and Related Daisies.” Plant Evaluation Notes. Number 30. Chicago Botanic Garden

“Shasta Daisy”: Kwantlen Polytechnic University. School of Horticulture Plant Database. Langley British Columbia.