Deciduous shrub or small tree to 5 m. Young branchlets glabrous or sparsely pubescent. Leaves pinnately veined, horizontal to ascending, strongly spicy-aromatic throughout growing season. Leaf blade obovate (to elliptic in smaller leaves), (4–)6–15 × 2–6 cm, membranous, glabrous to densely pubescent beneath, upper surface glabrous or with a few hairs on the midrib; base cuneate, margins ciliate, apex acuminate on larger leaves, acute to rounded on others; petiole ~10 mm, glabrous or pubescent. Flowers with 6 tepals. Drupe red, oblong, ~10 mm; fruiting pedicels of previous season not persistent on stem. (Wofford 1997, Bean 1981, Cullen et al. 2011).
Distribution Canada S Ontario United States Eastern: from Maine south to Florida, and west to Michigan, Missouri and E Texas
Habitat Mesic sites on acidic or basic soils: stream banks, understorey of low woods, margins of wetlands; 0–1200 m asl.
USDA Hardiness Zone 4-9
RHS Hardiness Rating H6
Conservation status Least concern (LC)
With its densely clustered, pale yellow flowers emerging before or with the young leaves in spring, small red fruits from late summer, and yellow autumn leaf colour, Lindera benzoin is at its best an attractive garden shrub, and one of the hardiest linderas. However, both male and female plants as well as optimal growing conditions are needed for maximum effect, and suckering from underground can be an issue.
Lindera benzoin is one of the species with deciduous, pinnately-veined leaves, although this says little about its relationships. It is most similar to, and probably most closely related to two much less common species from the American Southeast. L. melissifolia differs in being a low wetland shrub, rarely more than 1.5 m tall, with drooping, elliptic to ovate leaves with more or less rounded bases and with an acute but not acuminate apex (cf. held at or above the horizontal, obovate with cuneate base, and acuminate apex on larger leaves), as well as long-persistent fruiting pedicels. L. subcoriacea Wofford (probably not cultivated in our area but present in some southeastern American collections – Dirr 2009) is an evergreen shrub with smaller, leathery, less strongly aromatic leaves, found in acidic bogs (Wofford 1997). A limited phylogenetic study places L. benzoin (presumably along with these close allies) in a clade with East Asian species including L. metcalfiana (deciduous, pinnately veined), L. obtusiloba (deciduous, trinerved) and some evergreens (Zhao et al. 2018).
As a wild plant, Spicebush tends to favour fertile soil with plenty of moisture, where it can make extensive stands through a combination of seeding and suckering from underground. It is said to have been used as an indicator of fertile ground for agriculture by early European settlers (Snyder 2020). While it is very shade tolerant, growth is quicker where there is more light (Cipollini, Wallace-Seneft & Whigham 1994). Garden plants in full sun tend to be more dense and bushy than those in shade (Dirr 2009). Fertile, moist, well-drained soil and more or less full sun are probably optimal for garden performance (Dirr 2009). Lindera benzoin has such a wide range in eastern North America that there is almost bound to be variation in hardiness. The nursery trade seems to have neglected this, but for gardeners in the coldest – and perhaps the hottest – areas it would be worth seeking plants of appropriate provenance.
Like other linderas, the Spicebush is dioecious, with male and female flowers on seperate plants. Flowers of each sex include small, reduced versions of the other sex’s reproductive organs. Plants do not change sex, but a few individuals in some wild populations of L. benzoin have both male and female (but not hermaphrodite) flowers (Primack 1985). Both male and female flowers produce nectar, attracting those generalist pollinators – various bees and flies – whch are around early in the season (Niesenbaum 1993). In the garden, males are generally more showy in flower since the stamens contribute so much to their visibility. In the fruiting season females are more desirable, the red fruits attracting birds such as the Grey Catbird (Dumetella carolinensis) to gardens in North America even as they ripen (Gagliardi & Walker 2018), but a male is also needed for pollination. Herein lies the biggest drawback of Spicebush in small gardens – for maximum effect both sexes are needed, not only requiring space, but harder to achieve since seed-raised plants cannot be sexed until they flower.
Sex ratio in wild populations has been much studied, but no simple picture emerges, with reports of female-biased, male-biased and unbiased populations. Biased sex ratios tend to attract the interest of evolutionary biologists since well-established theory suggests that – all else being equal – natural selection tends to result in equal numbers of males and females (Fisher 1930). Long-term, multi-site studies by Martin Cipollini and colleagues are beginning to unravel some subtleties. There tends to be a female bias among smaller L. benzoin plants, a male bias among the largest ones, and a female bias in more recently established populations, which moves with time towards equality or even male bias (Cipollini et al. 2013; 2020). It has been suggested that faster growth rates and perhaps better herbivore resistance in females before reproductive maturity gives them an early advantage, but the higher resource cost of female reproduction gives males a competitive edge later in life.
Every part of the plant produces an aromatic oil. Crushed leaves emit ‘a pungent spicy odour too strong to be quite pleasant’ (Bean 1981). Not surprisingly, indigenous peoples across its natural range have used it to flavour food, as a tea, and as medicine for diverse ailments (Moerman 2003). There is a significant literature on the chemical composition of the oil and its drug potential (eg. Tucker et al. 1994).
Lindera benzoin was described by Linnaeus (1753) (as Laurus benzoin), the specific epithet referring to the smell of the fruits resembling gum benzoin (which is made from Styrax spp.). It is very clear that this American plant was well known to an earlier generation of European botanists and gardeners. Loudon (1844) gives 1688 as the date of introduction, and notes that by his day it was ‘not infrequent in collections’, offered in the British nursery trade, but still being propagated by imported seed. Loudon claims it as ‘rather tender’ in Britain, reflecting the climate of the time but perhaps also because early imports may have been from rather southerly populations, perhaps in Virginia.
Today the species is well represented in British, Belgian and Dutch collections, but less often planted by gardeners in general, eclipsed by the much showier L. obtusiloba. It is more often seen in North America, across its wild range and in the Pacific States, where it is prized for its reliable yellow autumn colour.
Propagation is usually by seed, which requires cold stratification. As with other linderas, cuttings have a reputation for being hard to root. Dirr (2009) notes that semi-ripe cuttings will occasionally root, but not in great numbers. One American nursery claims to have worked out an effective method but does not divulge the details (Broken Arrow Nursery 2023). The following forms and cultivars are rarely seen even in North America due to propagation difficulties.
Lindera benzoin 'Rubra'
Described simply as having ‘brick red flowers’ (Champlin 1977), it is clear from photographs that the tepals and bud-scales are red while the stamens are the typical yellow (Broken Arrow Nursery 2023). The winter buds are also a darker, redder brown than is typical. It is known only as a single male clone originally found at Hopkinton, RI, and cutting-raised material is commercially available in North America (Broken Arrow Nursery 2023). Whether this curiosity is better treated as botanical form or cultivar is a moot point. The existence of only a single clone might favour a cultivar (eg. Dirr 2009), but the latinized name is too recent to be valid. On the other hand its original name as a form appears to be validly published (Champlin 1977).
Lindera benzoin 'Xanthocarpa'
Ripe fruit orange-yellow. It is often listed as a cultivar, since a clone discovered at the Arnold Arboretum in 1967 by propagator Alfred Fordham seems to have been particularly important in gardens (Dirr 2009). However, it is clear that such plants turn up from time to time in wild populations (Anon. 2016), and it is validly published as a botanical form, based on material collected on the Massachusetts coast (Torrey 1914).
Particularly large, showy flowers; a male clone introduced before 2003 by Tom Clark, Fern Valley Farms, NC (Dirr 2009).