Q: We moved to a nicely landscaped home in Carmichael in March. The lush vegetation in our half-shaded garden included many pretty purple-green plants with broad heart-shaped leaves. The plants seem to be spreading and are beginning to shade out the dwarf citrus trees. Some are now 10 feet tall as they begin to bloom with clusters of pink flowers.
I would like to know what plant this is and whether it will continue to be invasive throughout the garden. It appears to be a perennial that dies back in the winter, but it is becoming massive and even sprouting under the fence into the neighbor’s yard. Can you give me any information or advice?
Mary Mallory Rogers, Carmichael
A: Your garden must be popular with butterflies and hummingbirds. They both love that unusual plant with big clusters of tubular pink flowers. But as you’ve seen, it can grow very quickly and become a garden thug, overwhelming its neighbors.
From your photos, your mystery plant appears to be Clerodendrum bungii, also known as rose glory bower (or glorybower), Mexican hydrangea and Cashmere Bouquet. That last nickname gives it an important footnote in fragrance history. It’s believed to have inspired the scent for Cashmere Bouquet soap, introduced by Colgate as the first milled perfumed toilet soap in 1872.
The actual flowers, which are in bloom from late spring through frost, have a lovely scent, too. Glory bower is grown for its heart-shaped foliage as much as its abundant bloom. Tolerant of sun, it fills in shady corners under trees or along fences. It prefers at least partial shade and moist growing conditions. With abundant water, it can grow quite tall – as you’ve seen. By cutting back its water supply (to once a week irrigation, for example), you can keep this shrubby perennial under 3 or 4 feet tall. It’s also shown a lot of drought tolerance.
Glory bower spreads by underground stems or rhizomes; that’s why it’s poking under the fence into the neighbor’s yard. (It’s considered a member of the mint family so treat it similarly.) It can become very aggressive around the landscape, and some states – particularly in the Deep South from Texas to Florida – consider it an invasive plant. Like bearded iris, the rhizomes can be dug up and divided.
By controlling the rhizomes, you can control glory bower. To contain their growth, put some sort of barrier around the rhizomes when you replant them. Bricks or concrete blocks sunk into the ground work well; so does a 6-inch wide strip of metal – such as the barriers used to contain bamboo growth – buried in a circle around the rhizomes. Or plant the rhizomes in a pot and submerge the pot in the ground.
Native to China and Northern India, glory bower likes warm and tropical conditions, growing into a thick shrub. In Sacramento, it dies back each winter, when its rhizomes can be dug up and divided.
Cut it back as needed to avoid shading your citrus or other neighboring plants. Glory bower behaves like mint; once established, it’s usually there to stay.
Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties. Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to firstname.lastname@example.org. Please put “Garden Detective” in the subject field and include your postal address. To contact UC Extension directly, call:
Sacramento: (916) 875-6913; 9 a.m.-noon and 1-4 p.m. Monday-Thursday
Amador: (209) 223-6838; 10 a.m.-noon Monday-Thursday; email ceamador. ucdavis.edu
Butte: (530) 538-7201; 8 a.m.-noon and 1-5 p.m. weekdays
Colusa: (530) 458-0570; 9 a.m.-noon and 1-4 p.m. Tuesdays; website: cecolusa.ucanr.edu
El Dorado: (530) 621-5512; 9 a.m.-noon Tuesday-Friday
Placer: (530) 889-7388; 9 a.m.-noon Tuesday-Thursday or leave a message and calls will be returned; website: pcmg.ucanr.org/got_questions
Nevada: (530) 273-0919; 9 a.m.-noon Tuesday-Thursday or leave a message
Shasta, Tehama, Trinity: (530) 225-4605
Solano: (707) 784-1322; leave a message and calls will be returned
Sutter, Yuba: (530) 822-7515; 9 a.m.-noon Monday-Tuesday and 1-4 p.m. Thursdays
Yolo: (530) 666-8737; 9-11 a.m. Tuesdays and Fridays, or leave a message and calls will be returned