Notes from the Garden: Trees and Shrubs That Thrive in the Shade
I grew up in a small town in rural Connecticut. Behind the house there was a brook and a hardwood forest with a high canopy of old maples that created a cool space for spending hot summer days. My favorite understory tree was a small, bushy tree that had very fragrant leaves and stems, which I decided must be witch hazel, as the barber splashed witch hazel on my neck after each haircut, and it was vaguely the same. I frequently chewed on the leaves and green twigs in lieu of the chewing gum that was forbidden to me.
This summer I discovered the name of that plant: spicebush (Lindera benzoin). One of my gardening clients had requested one for her garden, and as soon as I crushed a leaf, I was transported back 60 years. I knew it immediately. Most winters my part of New Hampshire drops to minus 25 degrees, so any plant that will survive here must be rated for Zone 4 (minus 20 to minus 30). I checked my favorite tree book (Michael Dirr’s Manual of Woody Landscape Plants), and sure enough, spicebush is rated for Zone 4. I will get my own as soon as I find the right place on my property to plant it.
From Dirr’s book I learned that spicebush can get to be up to 12 feet tall and wide, and is in the laurel family. There are 80 species of Lindera, both deciduous and evergreen (L. benzoin is deciduous). Apparently it blooms in early spring, but the yellow blossoms are tiny, only one-fifth of an inch across; I have no memory of it blooming. Fall leaf color is yellow. Dirr’s book says it does well in moist, well-drained soils in full sun or half shade, though in my experience it will do well in dry shade in open woodlands. Dirr says spicebush is not often found in nurseries, but E.C. Brown’s Nursery in Thetford Center has several nice ones.
Another woodland plant that I would like to try is leatherwood (Dirca palustris). Like spicebush, this is a native shrub that will grow in shady areas but this one prefers moist to wet soil, something my land has plenty of. Apparently it grows to be only 3 feet to 6 feet tall and wide, and is more open and spreading in shade than in sun. It is has small yellow flowers that bloom very early in the spring, well before the leaves emerge. Native Americans used the bark to make bow strings, fish lines and baskets. Tough stuff.
Three years ago I planted a sweetshrub or Carolina allspice (Calycanthus florida). The first two years I grew it in full sun with deep, rich moist soil. Both years the leaves yellowed, as if the sun were too strong and bleached them out. So last fall I moved it into a grove of old wild apples that provide full shade, and it seems to be doing much better. It is blooming now, and has put on considerable new growth.
Sweetshrub grows to be 6 feet to 9 feet tall with a spread of up to 12 feet. Some varieties have very fragrant flowers, but mine does not. Dirr’s book suggests buying the shrub in bloom in early summer, as the fragrance varies from plant to plant. It is adaptable to acid or alkaline soils, and is hardy to Zone 4.
Mountain laurel (Kalmia latifolia) is another fabulous shrub that will grow in deep shade (or even full sun), and I have grown it these past 20 years or so, even though I am on the northern edge of where it is successful. Mine produces delicate three-quarter-inch diameter flowers, cups of white with pink veins. After cold winters I don’t always get flowers. There are cultivars with flowers in white to rose, and everything in between. Definitely buy when it’s blooming. It does best in acidic soil that is cool and lightly moist. I have seen it growing abundantly in the wild at Sleeping Giant State Park in Hamden Conn., where there is a high, dry, open hardwood forest.
Of all the shade-growing woody plants, the most dramatic on my property is the climbing hydrangea (Hydrangea anomala subsp. petiolaris). I have vines that completely cover the north side of my barn and that only get a few hours of sun each day. It is in bloom now, with flower corymbs (flat topped inflorescences) that have both fertile and sterile (showy) blossoms and are 6 to 10 inches across.
Climbing hydrangea is slow to get established, mine took six years, but once it begins to grow it quickly covers a surface. It will attach itself to stone or brick, but needs to be strapped onto wood surfaces, at least at first. Mine has grown through the cracks on the barn and is now self-supporting. Its vines can grow 60 feet or more, and has support arms for its flowers that reach straight out from the barn that are up to 3 feet long. It is truly dramatic.
So don’t despair if your property is mostly in the shade. There are these plants, and lots more, that will amaze and delight you.
Henry Homeyer is the author of four gardening books. His website is www.Gardening-Guy.com.