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Stout Silver Medal Daylily Garden

The genus Hemerocallis, common name daylily, is comprised of about 20 species, only a few of which are widely grown. Modern daylilies are the result of previous crosses made between several species and thus are not given a species designation. One of the most prominent early hybridizers was Arlo Burdette Stout who began his work at the New York Botanical Garden in the 1930’s. He is considered the “father of the modern daylily” and the highest award given to a cultivar by the American Daylily Society (ADS), formerly known as the American Hemerocallis Society, is the Stout Silver Medal. To be considered for this award a daylily must first have received an Honorable Mention and then an Award of Merit from the ADS. It generally takes at least ten years from the time a daylily has been introduced for it to ascend through the ranks to be eligible for the Stout Silver Medal. The award has been given annually since 1950 and is voted on by trained ADS judges.

The common name, daylily, reflects the fact that individual blooms only last for one day. However, bloom time for a clump of daylilies is extended by multiple buds on a scape (flower stem) and scape branching. Thus they make excellent and carefree plants in the sunny garden but can be challenging to use in floral arrangements. They generally bloom in July and are welcome additions to the garden following the bursts of color from spring and early summer bloomers.

The display of the Stout Silver Medal winners surrounding the Beckwith Pavilion shows the evolution of the modern daylily. You will notice that many of the earliest varieties bear either yellow or orange flowers with fairly narrow, smooth-edged petals. Newer awardees often have wider petals and come in an array of colors. Diamond dusting, distinct eye zones (e.g. ‘Carnival in Mexico’), ruffled or toothed edges (e.g. ‘Entwined in the Vine’), and different flower forms such as the spider form (e.g. ‘Skinwalker’) or double flowers (e.g. ‘Dorothy and Toto’) are exhibited among the newer varieties. Breeders work with both diploid  (2 sets of chromosomes) and tetraploid (4 sets of chromosomes) forms. Tetraploid cultivars generally have thicker flower scapes and flowers with more substance. The first tetraploid daylily to win this award was ‘Mary Todd’ in 1978 but since 1994, tetraploid cultivars have dominated this award category.

The collection at the Arboretum was started in the mid 1990’s by Lois Girton who was inspired by reading “A Passion for Daylilies” by Sydney Eddison.  She contacted local daylily enthusiasts for donations of plants.  One person she contacted was Max C. Olson of Des Moines who subsequently became a valuable volunteer and benefactor of the Iowa Arboretum and Gardens.  One of the projects he undertook was entering the accession records into an electronic database which is still used today at the Arboretum.

Although at the time the collection began there was no obvious connection to Iowa, the Iowa Arboretum and Gardens is especially excited to showcase the 2019 Stout Silver Medal winner, ‘Scarlet Pimpernel’, bred by former board member Nan Ripley of Nevada, Iowa. The garnet red and yellow flowers (Iowa State University colors!) have green throats.  ‘Scarlet Pimpernel’ was registered in 2006.  Nan has registered 64 cultivars of daylilies since 2003.

Looking for more daylilies?  There are also hundreds of daylilies in the Perennial Garden.


Click for List of Stout Silver Medal Daylilies (The Arboretum has all but three of the 72 winners.)

Click for Photos of Stout Silver Medal Daylilies

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