Garden Detective

Garden Detective: Grandma’s mystery plant has him guessing

Please help identify this hardy plant that has arisen annually in my grandmother’s garden for at least 90 years. It grows to about 10 inches tall and the berries turn from green to orange as the season progresses.

– Allen Schaad, Sacramento

According to UC master gardener June Bleile and judging by the photo you provided, your mystery plant likely is Arum italicum, also known as Orange Candlestick, Cuckoo’s Pine and Italian Lords and Ladies. This perennial is not native to California but has naturalized in the wild.

It is propagated via birds and animal-dispersed seeds and hardy underground corms. Care should be taken when handling arum as all parts of the plant are toxic and will cause severe pain in the mouth and throat if eaten. The plant and seeds also are irritating to the skin. Make sure to wear gloves if working in the garden around arum or pulling it out.

Arum blooms in the spring with whitish green flowers that turn to showy red seeds later in the season.

No wonder this plant has survived in your grandmother’s garden nearly a century. Arum is notoriously difficult to eradicate once established. There is no broadly accepted method of control or treatment. Herbicides only provide temporary relief and won’t keep the plants from spreading via underground. Even burning won’t stop it; burning eradicates only the foliage.

If you do pull arum out, do not put any part of the plant into green waste containers or your compost pile; it will survive and thrive anew. Instead, put it in the garbage for disposal.

I would love to know what this plant is called. The friend who has the plant tells me it is an old-fashioned shrub that grows to as much as 5 feet high, maybe more, and has this lovely pink-red flower on it. The flower itself is about 4 inches long.

Nancy Long-Hine, Sacramento

According to UC master gardener Annie Kempees, the common name for this lovely plant is Brazilian Plume Flower. The botanical name is Justicia carnea and it is in the same genus as the shrimp plant.

Justicia carnea likes dappled to full shade, rich soil, regular to ample water (every three to five days). As its nickname implies, it originates from South America.

According to the Sunset Western Garden book, the Brazilian Plume Flower does well in zones 8, 9 and 13 through 24, H1 and H2. Elsewhere, it is grown as an annual. It is erect, soft wooded, growing 4 to 6 feet tall and up to 3 feet wide. Its leaves are prominently veined and grow to 10 inches long.

This shrub blooms mid-summer to autumn; the flowers are tubular, dense clusters of pink to crimson. “Huntington Form” is a more compact variety ((under 4 feet tall) with deeper pink flowers and leaves that are bronze on the under surfaces. Both varieties make an excellent plant for shady, narrow spaces.

Cut back plant in spring to encourage strong new growth. But give it a sheltered spot; this tropical plant is not frost hardy. Upper portions of branches may freeze at 29 degrees.