A trip to Boston had me roaming around the Arnold Arboretum with Fred on a rainy Tuesday morning. Rainy days are always contemplative ones for gardeners. One of our usual concerns, getting our favorite plants the water they need, is relieved (provided the rain is not coming down in torrents and washing them away, which on this given morning, happily, it was not). And this allowed me to ponder something else, the purpose and life of woody plants.
What better place to ruminate on woody plants than at the Arnold Arboretum? Its collection is filled with accessions from the United State and around the world, many of which were given to the Arboretum (a part of Harvard University) by explorers like Charles Sprague Sargent and Ernest Henry “Chinese” Wilson when they arrived back in the States from plant hunting expeditions in Asia and other then exotic locales.
With some exceptions, trees and shrubs often get less consideration from new gardeners who are understandably coping with the overwhelming choices of perennials, annuals and bulbs. This struck me especially clearly last weekend when one novice was still assuming that all conifers were pines, while his more knowledgeable hosts were struggling to identify the species and variety of a pair of wildly divergent smokebushes on their property.
While we love trees, there is the danger that we take them for granted as already extant in the landscape. But woodies can send an experienced gardener into paroxysms of delight. Of course, they can also lead to terror when we have to choose between them (the Sophie’s Choice moment of gardeners on small acreages.) It is easy for us to imagine a perennial getting to three feet tall and two feet wide, but how does one deal with planting a tree that might grow to two hundred feet tall? These decisions loom larger, like the plants themselves, as is self-evident when one sees mature specimens of katsuras and dawn redwoods towering above, but is true of smaller trees, too.
And if ever there was a place to see the mature size of a paperbark maple or a Japanese stewartia, it is the Arnold. Seeing them full size also makes us understand why it is essential to think carefully before planting. Although some perennials, like Baptisias, are said to resent transplanting and should therefore be sited carefully, this is fourfold true for many woody plants. It’s not just that the gardener will resent transplanting when a rare magnolia, for instance, may need to be moved because it was misplaced to begin with. The tree itself will resent having to be moved. And some tap-rooted woodies will not only resent transplanting, but may end up taking their own lives. Every gardener who has placed a small sapling in a spot that it soon outgrows has faced the resultant options, none of which are good: the backbreaking work of moving the plant, the awful decision of either taking the plant’s life or trying to manage its size with endless structural pruning, or moving the house fourteen feet over so the plant has room to grow!
But a rainy day reminds us of many other considerations beyond size when selecting woody plants for our gardens. I ask myself the same questions as in many other parts of my life: what am I looking for? and what are my needs? Flowers, fragrance, protection from the sun, fall color? As the years and seasons progress, those needs evolve, sometimes almost daily. On this day, in the rain with a beagle in tow, the treetops above were meeting one of my needs: they softened the blow of the occasional downpours of rain that settled over us. On other days, this overstory might serve as protection from the sun’s rays. And trees don’t provide this protection from the elements only for us but also for some of the plants that live in the understory. A variegated dogwood that we passed made this even clearer as it sat above other plantings, almost as if holding an umbrella over its fellow inhabitants of the garden.
This sense of overstory made me rush up Explorer’s Hill to see one of my favorite trees, the Seven-Son Flower, which has a broad canopy that feels like an umbrella overhead. The multi-stemmed specimens of this species here are spectacular, with white exfoliating bark that competes with the glorious bark of the aforementioned stewartias and paperbark maples. Besides that, the sweet scent of its flowers in late summer would be reason enough to grow it.
The thought of fragrance sends me on another track, running off to find the remaining lilacs in bloom. This was one of the rare moments when my own sense of smell proved almost as capable as Fred’s, as the sweetness of a Japanese tree lilac led me down the hill to a beautiful specimen of this, in my opinion, underutilized woody. And to other late blooming lilacs, such as ‘Miss Kim’ which enlivens this garden and my own well after the common lilacs have passed by. And if fragrance is of interest, why not consider adding a mock orange, with its fragrant white flowers, to your garden? As the Arnold shows, there are plenty to select from.
I could go on, but like Fred, I am now distracted by what lies ahead and am just going to take it all in as we plod forward in the rain, taking in all that the world has to offer. After all, it’s not just plants that need a rainy day and a chance to dream.
A gardener grows through observation, experimentation, and learning from the failures, triumphs, and hard work of oneself and others. In this sense, all gardeners are self-taught, while at the same time intrinsically connected to a tradition and a community that finds satisfaction through working the soil and sharing their experiences with one another. This column explores those relationships and how we learn about the world around us from plants and our fellow gardeners.