A tale of two Cornus collections

by Debbie Merriam, Director of the Wakefield Arboretum
June 20, 2019

Kousa dogwood flowers

A tale of two Cornus collections

Kousa dogwood flowers

The true flowers of Kousa dogwood (Cornus kousa) are inconspicuous, but surrounded by showy white bracts in June. Photo by Debbie Merriam.

Part of the Mary M. B. Wakefield Charitable Trust, the Wakefield Estate and Arboretum in Milton is home to an extensive collection of woody plants, the highlight more than 300 Kousa dogwoods (Cornus kousa). Mary (Polly) Wakefield passed away in 2004 and left her property in a private trust to be used for education and community engagement. A formally-trained landscape designer, Wakefield developed an interest in plant propagation and took classes at the Arnold Arboretum with staff propagators Roger Coggeshall and Donald Wyman. Her interest in the Kousa dogwood (native to Asia, a tree small in stature with lovely red fruit and creamy-white bracts; false leaves surrounding inconspicuous true flowers) started at the Arnold Arboretum, where she collected seed from the same three trees at the top of Bussey Hill for 34 years.

Wakefield planted these Arboretum-derived seeds on her property, eventually developing a collection of 600 Kousas, including seven cultivars she patented. Today the Wakefield Estate and Arboretum still stewards Polly’s collection of the trees, all showing unique characteristics that include lovely bracts, bark, leaves, fruit, and bark. In 1990, Wakefield published an article [pdf] in Arnoldia entitled “A Fascination with Dogwoods” that explained her interest in Kousa dogwoods and the role the Arnold Arboretum played in the development of her collection. Polly remained committed to the institution, serving on the visitation committee and bequeathing financial support to the Arnold Arboretum Horticultural Library.

Wakefield Estate Kousa collection 2019 Debbie Merriam

Hunnewell Interns Lane Diesa and Grant Hughes (from left), Seasonal Gardener Lee Toomey (obscured), and Manager of Plant Production Tiffany Enzenbacher (right) collect cuttings of choice Kousa dogwoods at the Wakefield Estate. Photo by Debbie Merriam.

This past winter while reviewing Polly Wakefield papers, Debbie Merriam, Wakefield Arboretum director, discovered Arnold Arboretum greenhouse propagation cards for Wakefield’s Kousas. These propagation cards were dated between 1960 and 1970 and were for several of Polly’s patented cultivars. Interested in rekindling the collaboration between the Arnold and Wakefield, Merriam contacted Tiffany Enzenbacher, Arnold Arboretum Manager of Plant Production about propagating some of Wakefield’s trees. Enzenbacher—intrigued after reading Polly’s Arnoldia article—agreed to propagate some of the Kousas from the Wakefield collection.

On June 18, Enzenbacher, Hunnewell interns Lane Diesa and Grant Hughes and seasonal gardener Lee Toomey visited the Wakefield Estate to collect Kousa cuttings for propagation. Merriam and Erica Max, Wakefield program and education director, selected 10 Kousas from the Wakefield collection for propagation. Their selection was based on several factors that included the original seed plantings, DNA matches to Polly’s patented cultivars, and unique characteristics including brilliant fall color, unusual bracts, and double bracts. Enzenbacher and her team moved through the collection to the marked trees, selecting cuttings from new spring growth which offer the best results when propagating. Wakefield staff members were enthusiastic to see the Arnold Arboretum interns and staff collecting cuttings and reestablishing this fascinating connection between the two institutions after so many years. By noon the collecting was complete: almost 500 cuttings for propagation. Enzenbacher and her crew headed back to the Arnold Arboretum with the fresh cuttings to be “stuck” in growing medium before the end of the day.

Tiffany Enzenbacher kousa propagules

Stuck cuttings of Wakefield Estate Kousa dogwoods at the Dana Greenhouses. Photo by Tiffany Enzenbacher.

Back at the Arnold Arboretum greenhouse, the cuttings were sorted, cleaned and prepped for propagation. Enzenbacher explained that the rate for survival is higher if the cutting is processed immediately after harvesting. Because many of the trees in the Wakefield collection are older, the rate of the cuttings’ survival decreases. However we are all hopeful that this collaboration will yield a new crop of Kousa dogwoods for replanting, or even patenting; but most importantly, we are pleased to re-establish this longstanding connection between two Arboretums: the Arnold Arboretum, one of the oldest such collections in the United States and the Wakefield Arboretum, one of the youngest.

One thought on “A tale of two Cornus collections

  1. Thank you.

    A visit to next year’s Dogwood Days on my 2020 calendar, paired with a visit to the Arboretum.

    The kousas have been outstanding this year, especially on Martha’s Vineyard.

    While more modest, I enjoyed the bloom time of the 2017 member plant Cornus kousa var. chinensis.

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