Clerodendrum trichotomum

Clerodendrum trichotomum
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Lamiales
Family:	Lamiaceae
Genus:	Clerodendrum
Species:	C. trichotomum
Binomial name
Clerodendrum trichotomum Thunb.

Clerodendrum trichotomum, the harlequin glorybower, glorytree or peanut butter tree,^[2] is a species of flowering plant in the family Lamiaceae. It is native to China, Korea, Taiwan, Japan, India, and the Philippines.^[3][4]

It is cultivated for its fragrant flowers, autumn color, and ornamental berries, which contain the novel blue pigment trichotomine.^[5]

Clerodendrum is derived from Greek; klero means chance and dendro means tree, so the name together translates to 'chance tree'.^[2][6] Trichotomum is also derived from Greek, and means 'three-forked' or 'triple-branched'.^[2][6]

In Japanese, this plant is called クサギ (kusagi, or "smelly tree"). It is not the only plant which is called this in Japanese, but is the primary plant associated with the name.^[7]

The leaves are dark green, ovate, up to 12 cm (5 in) long, soft and downy or hairy, and produce a "peanut butter" odor when crushed.^[8] Some varieties have toothed leaves.^[9] These leaves do not change color in fall, instead falling off of the tree still green with the first frost of the season.^[10] The fragrant flowers are borne on branching peduncles. They have 5 white petals, held within a green calyx which turns red as the fruits ripen.^[11] The flowers are not self-pollinating, so at least two plants are needed to produce fruit.^[10] The fruits (drupes) are white, changing to bright blue and eventually dark blue on maturity.^[2][12] The flowers appear in late summer and early autumn, and the berries can remain on the tree well into the winter season.^[2] Flowers and mature fruits can occur at the same time.^[9] The bark is brown, grey, has a smooth or lightly fissured texture, and has many lenticels.^[9][11]

It creates basal shoots continually and can grow 3–6 metres (10–20 ft) high, so it can either be shaped into a shrub, or can grow into a tree if it is allowed to grow tall, does not die back in the winter, and has the shoots trimmed.^[13]

It is deciduous, moderately drought tolerant, and is one of the most hardy of its genus, growing in USDA zones 7 through 10.^{[8][9][10][11][14]} It can grow in full sun or partial shade, but blooms best in full sun and prefers to grow near protective structures like walls; in exposed gardens, mulching in winter is often recommended to protect the plant.^[2][15][16] It prefers fertile, moist, well-drained soil, but tolerates soils that are acidic, loamy, sandy, or clay containing.^[2][13][16] It is reportedly easy to transplant, grows back well from roots,^[9] and according to the JC Raulston Arboretum, it can be propagated "from seed or cuttings taken from partially hardened wood in early summer and rooted under mist."^[13]

Common pests that affect C. trichotomum include whiteflies, mealybugs, and aphids.^[17]

The variety C. trichotomum var. fargesii (Farges' harlequin glorybower) and the cultivar C. trichotomum var. fargesii 'Carnival'^[18] have gained the Royal Horticultural Society's Award of Garden Merit (confirmed 2017).^[16][19][20] C. trichotomum var. faregesii is noted for its especially strong fragrance, even relative to other varieties within the same species.^[13]

The "Stargazer" variety has variegated leaves and the flowers have yellow margins.^[21][22]

The plant is cultivated decoratively, especially in areas like Europe and the Americas where it is not native; it is especially popular in the Southeastern United States.^[13] Some sources say the species is invasive in the US, while others say that it is naturalized.^[23][24][25] People sometimes shape it into hedges for privacy screening.^[26][8] They are reported to attract moths, butterflies, bees, and hummingbirds, and may be used in butterfly gardens.^[9][16][27]

In the parts of East Asia where it is native, the leaves are sometimes eaten, similarly to wild or foraged vegetables.^[7] They are boiled to remove the odor.^[9]

The wood is used to make clogs.^[9] In some Japanese villages, a type of grub found in the trunk is toasted and fed to children to calm them.^[9]

The berries contain the novel pigment trichotomine, and can be used to make natural dyes.^[5][9][28]

This species was first introduced into European cultivation around 1800.^[9] In the U.S. state of Arkansas, it was introduced from Japan by Russian botanist Karl Maximovich in the 1860s.^[10]

• Bunchosia argentea and Bunchosia glandulifera – also called "peanut butter fruit" or "peanut butter plant"
• Clerodendrum bungei – similar related species
• Dicentra formosa
• Euonymus alatus
• Iris foetidissima
• Magnolia
• Mimosa
• Peanut
• Phytolacca americana
• Sumac
• Teak
• × Chitalpa

• Hillier, J. and A. J. Coombes. The Hillier Manual of Trees and Shrubs. David & Charles. 2007.

• Plant profile at Oregon State University
• Post about the plant at Blithewold
• Blog post about making dye with the berries