Michael A. Dirr touts the superior adaptability and aesthetics of willowleaf spicebush.
Michael A. Dirr
The willowleaf spicebush, Lindera angustifolia (aka L. glauca var.angustifolia, L. glauca var. salicifolia, L. salicifolia), is an outlier in the realm of landscape shrubs/small trees, relegated to the shadows, but hopefully heading toward prime time. With ~100 Lindera species worldwide, only two, L. benzoin, our native spicebush (also L. melissifolia, native wetland species) and L. obtusiloba (China, Korea, Japan) have roots in commerce, albeit shallowly. I have grown the native species, and both suffer from any degree of extended drought. However, L. angustifolia offers superior adaptability, aesthetics and functional landscape attributes. Michael Van Valkenburgh, noted landscape architect, includes L. angustifolia in his designs. See his remarkable public and private gardens at www.mvvainc.com.
Three plants are ensconced in the Dirr garden in full sun to moderate shade, irrigated or subject to nature’s whims, yet have never flinched. Pristine through the seasons, with most visitors to the garden asking, “What is that plant?”
Typically a multi-stemmed shrub (also small tree), it grows 8-10 feet high and as wide or wider at maturity. It may reach 20 feet+ in the wild. Foliage is densely populated, creating a full, yet elegantly textured outline, with branches often splaying and arching. Longwood Gardens maximizes this effect by using it as a loose screen along the pedestrian walk leading through the parking lot. Its genetics do not permit “meatballism,” the process of unscrupulous pruning to create “Franken” spheres.
Leaves resemble those of Magnolia virginiana (sweetbay) and could be mistaken for the same. They are glossy, bright-green above, bluish-green to silver below, brilliant yellow, orange, and red in autumn, dying off ash- to gray-brown, persisting into winter and early spring. Foliage is quite frost resistant with no injury at 28°F in our garden. Through the seasons, foliage is consistently healthy, without an inkling of insect or disease issues. An added attraction is its resistance to deer browsing. Yellow flowers appear in early March in Athens before the leaves and do not overwhelm. Apparently dioecious, male in 3- to 4-flowered umbels, female in 2- to 7-flowered umbels. Fruit is globose, shiny black drupe, ripening in October-November. I have not witnessed fruits on my three garden plants, but have observed copious quantities at the Arnold Arboretum and the late Specialty Ornamentals in Watkinsville, Ga.
A lone plant of L. glauca, akin to L. angustifolia, with a more rounded leaf and similar fall color, produces abundant fruit each year in our garden. I have yet to witness a stray seedling or have been able to germinate one from this plant. In fact, cut tests show most are hollow.
Seed germination has been difficult, and in all my trials only one seedling resulted, which produced spectacular orange-red fall color. Pleasant Run Nursery in New Jersey offers container-grown plants and lists it as a PRN select plant. The nursery carries it under the L. glauca var. salicifolia name. The nomenclature is muddled as indicated in the list of scientific names. Germplasm Resources Information Network validates L. glaucaand L. angustifolia but not var. or species salicifolia. The Flora of China lists L. glaucaand L. angustifolia as valid but not L. salicifolia.
Growers might consider training L. angustifolia as a single-trunk small tree. The gray bark is smooth, similar to M. virginiana. Based on stellar performance during the 2016 summer in Athens, the hottest on record and close to the driest (especially during late summer-fall), it has potential for high-stress environments. Based on my sightings around the U. S., it is cold hardy to Zone 6.
For more than 40 years, horticulturist, breeder, and author Michael A. Dirr has impacted the green industry through research, teaching, books, and plant introductions. firstname.lastname@example.org