Discover Witchhazels at the Arboretum

by Anthony S. Aiello
Curator and Director of Horticulture

No garden is complete without a witchhazel. While this is a strong statement, it is one that is easy to understand when you visit the Arboretum on a late winter day. Concentrated in the English Park section along the Mercury Ravine, but also planted throughout the rest of the collection, our witchhazels give visitors great enjoyment in the winter garden.

The curious small and fragrant flowers of the witchhazel bloom from late January through March and are true harbingers of spring. There are an array of flower colors, from bright or golden yellows, to oranges, rust and ruby reds. Three commonly grown witchhazels bloom in late winter: the Chinese witchhazel, (Hamamelis mollis), hybrid witchhazel (H. x intermedia), and the North American vernal witchhazel (H. vernalis). In general, these plants are large shrubs that prefer light shade, slightly acidic and reasonably moist soil. All our perfectly hardy in our area.

Hamamelis molis

The Arboretum has a very large and nationally significant witchhazel collection. Currently, close to 30 types of witchhazels are planted throughout the garden, with another 25 types being produced in our greenhouses. With so many varieties of witchhazels, many of these are confused in the nursery trade. With this in mind, Chris Strand, director of Green Spring Gardens in Alexandria, Virginia and I created the Witchhazel Introduction Program (WHIP). Our goal was to introduce verified cultivated varieties into the United States and establish reference collections at both of our institutions. Although witchhazels are of North American and Asian origin, Europe has been the center of most of the breeding and selection of this genus over the past several decades, however many of the European witchhazel selections are not properly identified or not well documented in the United States. To rectify this situation, in 2004 Chris Strand and I traveled to England, Belgium, and The Netherlands. Our goal was to collect propagation material from the original specimens of the most significant European ornamental witchhazel varieties, thus providing properly identified selections for botanic gardens, nurseries, and gardeners.

 
The Arboretum has participated in numerous collecting trips to natural areas in Asia, the Caucasus, and the United States, but this trip was unique in targeting cultivated plants. The methods and purposes were the same – to insure proper collection, identification, and cultivation of plants - but the focus was different. On the trip we visited a private nursery with the English national witchhazel collection, several public gardens such as Kew, Wisley, and Hillier’s, and private and public collections in Belgium and The Netherlands.
 
We timed our visit in order to see the witchhazel collections at the height of their bloom, providing us a sense of the diversity of the genus. We saw and collected from plants with an astonishing array of flower colors, from pale yellows and golds to auburns and claret reds. In total we returned with 32 types of witchhazels, 18 of which were new to the Arboretum. Some of my favorites were H. ´intermedia ‘Burnt Embers’ with rich yellow and auburn flowers, H. mollis ‘Imperialis’ with abundant golden flowers, and at Kew, one of the original Chinese witchhazels introduced into Western cultivation.

Upon returning, we promptly grafted the scions and placed the plants in a cool greenhouse. Unfortunately, our luck then took a turn for the worse; we had very little take on our grafts and an almost complete crop failure. If we should plan a future collecting trip back to Europe it will be in late summer, a time of year when witchhazel grafting is more successful.
 
The name witchhazel refers to the plants alleged ability to dowse or divine water. And yes, the bark of the witchhazel plant is the source of the astringent lotion. So if you are looking for an outing this winter, visit our witchhazels and I am sure you will agree that you need at least one in your garden. Some of the best cultivated varieties are: