Bob Keller of Illinois registered this medium size cultivar in 1991 as a sport of H. 'Halcyon'. It grows to 16 inches high and 40 inches wide with slightly wavy foliage with deep veins and thick substance. The pale lavender flowers bloom starting in late July.


 

An article about H. 'Canadian Shield', H. 'Devon Green', H. 'Peridot' and H. 'Valerie's Vanity' by Warren I. Pollock in The Hosta Journal (1997 Vol. 28 No. 1) states that, "These four hostas are mutations of 'Halcyon', arguably the best of the late Eric Smith's blue-leaved Tardiana Group...Are all four cultivars the same? I haven't seen any evidence they are different."

An article about the Halcyon Group by Peter Cross in The Hosta Journal (2004 Vol. 35 No.2) says, "...'Halcyon' is a first-generation member (TF 1 × 7) of the legendary Tardiana Group of hostas, which consists of hybrids of 'Tardiflora' × H. 'Elegans', produced in England by Eric Smith,  the master hybridizer of blue hostas, in the 1960s....Traditionally, sporting involves the cells in a section of a leaf (either margin or center) changing color...These sports simply lack the wax coating that makes the hosta leaves appear blue...I find it impossible to see any differences between these green sports..." Cross lists the all-green sports of 'Halcyon' including:

H. 'Devon Green' H. 'Valerie's Vanity' H. 'Canadian Shield' H. 'Peridot'

H. 'Emerald Coast' H. 'Grünspecht' H. 'Kryptonite'

An article by Warren I. Pollack in The Hosta Journal  (2020 Vol. 51 No. 1) titled Doppelgänger Hostas: Fancy Name for Look-alike Hostas, included a long list of hostas which various hostaphiles, published articles or other sources have indicated "look" the same. Some of these are, in fact, the same plant with two or more different names. Others are hostas that vary in some minor trait which is not immediately discernable to the casual observer such as seasonal color variations, bloom traits, ploidy, etc. So, as Warren mentions, hostaphiles may differ as to the plants listed but then, their opinions are based on visual observations and interpretations.

H. 'Canadian Shield', H. 'Devon Green', H. 'Grünspecht', H. 'Kryptonite', H. 'Peridot' and H. 'Vallerie's Vanity'.