Musings » Native Trees, Shrubs and Vines: a guide to using, growing and propagating North American woody plants
Boston -- New York
Houghton Mifflin 2002
William Cullina manages the Garden in the Woods, headquarters of the New England Wild Flower Society. He is the chief propagator at the garden and has grown almost all the plants he lists in his book. Plants have interested him from childhood. He has travelled all over the United States and Canada to find and photograph the native flora.
Cullina writes with passion. Even the introductory matter laying out the principles of taxonomy has some life in it. I was impressed by his comments that we need to cosider geological time when deciding what constitutes a “native” plant. The thousands or even tens of thousands of years needed for a species to become separate, and establish itself in an endemic region aren’t very significant on a geological time scale.
The fascinating conundrum of how almost identical genera and species arose in more than one endemic area, such as maples in New England and China, or rhododendron in the Pacific Northwest and the Himalayas, was plausibly explained by Asa Gray in the mid-nineteenth century. He showed that these parallel developments followed the line of departing glaciers.
At one time in remote pre-history, the continents were not yet split apart by oceans and the same plants were found throughout. When the continents divided and subsequently glaciers receded to an equivalent level on the now separate land masses, the plants remained similar. Where one segment of a glacier cut much further into the continental terrain, the longer duration of sever cold killed many of the species. There are more than 30,000 species of plant in China, whereas there are about 15,000 to 20,000 in North America. The glaciers did more damage in this country.
Cullina has handsome photographs of each species and a great deal of practical information on every page. I particularly liked the Leucothoe or Dog Hobble. It appears to be indestructible as well as having extemely pretty chains of flowers. Two years after he and a colleague forgot about a branch which they had shoved into a shallow pit and given only a perfunctory watering, it had taken root and grown into a whole new plant.
There are lists of native plant nurseries, replacements for invasive exotic plants and valuable technical information about how to propagate the seeds successfully at the end of the book.