By Sarah Robertson
Garden columnist | Posted: Saturday, June 27, 2009 12:00 am
Several years ago, while relaxing in a friend's lounge chair on a recent balmy summer evening, I caught the faintest scent of jasmine-lemon drifting across their patio.
The fragrance proved elusive and I finally gave up trying to pinpoint the source. But a few afternoon's later, while admiring another friend's recently-completed flower border, a tree that I had always assumed was some sort of birch cultivar suddenly caught my attention. It's slender, flower-laden branches dangled directly above my head and, as the breeze shifted, I realized that I had found my mysterious fragrance in, of all things, a linden tree.
I must confess that my attempts to incorporate fragrance into my own garden rarely extends beyond roses, lilies, nicotiana and the occasional deciduous azalea. I hardly ever think of trees, which is a downright shame. There are several terrific species to consider, many of them quite well-mannered and appropriate for gardens of all sizes.
Need more convincing? Consider the following three choices, then do a bit of research at your favorite local nurseries. Pressed for space? Banish any shrub or group of perennials that have languished for more than two seasons. They're taking up valuable space that you could put to better use (a tree, perhaps?!) and truly don't deserve a spot in your garden.
Many thanks to Kim Tripp and the late J.C. Raulston for their wonderfully helpful book, "The Year in Trees" (1995. Timber Press, 444.95 hardback), from which much of the following information on lindens was gleaned.
Linden (Tilia species): There are literally dozens of different species and cultivars of this magnificent shade tree. This complex genus, over which taxonomists still bicker on just how to classify the various North American forms and hybrids, includes forms ranging from our native Tilia americana to European and Asian species. Most are relatively tall, eventually broad-spreading, deciduous trees with gray, furrowed trunks and deep grass-green, glossy, oval to heart-shaped foliage that usually doesn't develop significant autumn color.
Linden foliage can be quite handsome, especially on some of the European forms. And in early to mid-summer, when warm weather hits and it finally feels like summer, lindens are covered with lacy clusters of tiny cream-colored flowers that smell absolutely delicious. Theirs is not an overpowering scent, but light and clean … a pervasive and captivating fragrance sure to capture your heart. The flowers eventually mature into interesting nutlets that are attached to a single, winglike, papery bract.
Lindens are typically hardy to at least zone 5. Although they prefer a moist, fertile and well-drained site in full sun, they tolerate a range of conditions. They don't seem to mind clay, adapt to a wide pH range, are very tolerant of drought, pollution and urban environments - a great street tree!
There can be occasional problems with insects (aphids) and disease (powdery mildew), but good sanitation and air circulation can help prevent problems from developing.
A few especially choice lindens for Western Oregon include:
Tilia cordata: Also known as littleleaf linden, this European species has small and very neat foliage, which gives it a greater elegance than some of its American or Asian cousins. There are a number of very nice cultivars, including 'DeGroot" (lovely glossy foliage, slower overall growth); 'Greenspire' (excellent foliage, terrific branching structure); 'Morden' (slow-growing, with a neat and formal outline); 'Pendula Nana' (a dwarf form with somewhat pendulous branch tips, making it a nifty container tree for tight spaces); and 'Rancho' (an especially floriferous selection with an intense yet pleasant fragrance).
Tilia x euchlora: Also known as Crimean linden, this smaller species generally grows 25-35 feet tall (perhaps, eventually, to 50 feet over many years). Less dense than littleleaf linden, this species generally casts more open shade. It has a less formal, habit than littleleaf linden and is considered among the most graceful of lindens.
Tilia tomentosa: Also known as silver linden, it's named for its two-toned foliage, which is deeply glossy green on the surface and silvery white on the underside. This eye-catching effect is quite magical when a breeze ruffles the foliage. The bark is a smooth silver-gray and the tree is a bit smaller and rounder than its cousin, the littleleaf linden. A fine cultivar is 'Sterling,' which has remarkably silvered leaves.
* Silk tree or mimosa (Albizia julibrissin): Native to Asia, this broad-canopied, deciduous tree is best known for its fluffy pink, pincushion-like blossoms, which sit atop fern-like foliage in late July through mid-August.
Although this tree can easily reach 40 feet, it can be headed back when young to make a 10-20-foot umbrella-shaped specimen. The delicate foliage is light sensitive, folding up tightly at night.
This tree is best placed near the edge of a property, since it tends to be somewhat messy at season's end when the delicate tiny leaves, flowers and seedpods fall to the ground. But it's marvelous form, incredibly scented flowers and unique foliage make it a charming addition when properly placed.
In our neighborhood, a mature silk tree belonging to a neighbor scents the air for a good one-block radius. It's sweet without being cloying and has the added bonus of attracting many, many hummingbirds
* Fragrant snowbell (Styrax obassia): Although its cousin, Styrax japonica (Japanese snowbell), is a familiar garden element, the snowbell is less well known.
Native to eastern Asia, this charming tree deserves greater recognition. At 20 to 30 feet tall, with oval leaves that are olive-green above and a downy cream below, this particular species takes up less room than its cousin, the snowbell. A friend's tree, now about 10 years old, is shaped like an elongated oval, about 12 feet tall and seven feet wide at its widest point. The late-spring flowers appear in terminal wands of 30 to 40 blossoms - fragrant and very, very lovely.
This tree is happiest in fertile, moist soil. Under such conditions, it handles full sun quite well. When conditions are less optimum, give it a site in dappled shade.