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Romneya trichocalyx

From southwestern California, this semi-shrubby perennial in the poppy family bears the largest white flowers with a yellow center and a bristly calyx, rises from rhizomes, is drought-tolerant, and native to dry canyons and chaparral.

Is Romneya trichocalyx growing in your garden? Record it and all of your plants in Known.

Common Names

Bristly Matilija Poppy, Matilija Poppy, Hairy Matilija Poppy

Summary

Native to southern California and Baja California, this Matilija poppy is a shrub with a rhizomatous root system and an upright, spiky growth habit. It bears very large, solitary flowers at stem tips, with six white petals surrounding a yellow center, and a dense covering of bristle-like hairs on the calyx that give it a hairy appearance.

In cultivation, it requires full sun and very well-drained soil, tolerates sandy or gravelly substrates, and is very drought-tolerant with minimal irrigation once established. It is native to dry washes and canyons in chaparral and coastal sage scrub and propagates by rhizomes in winter (rhizome disturbance often fatal) or by seed, though seed propagation is difficult; maintenance includes cutting to about 6 inches in late summer/fall and mulching dried stems; hardy to 4,000 feet and pH tolerance from 5.0 to 8.0. Widely used as an ornamental plant in landscapes.

Lifecycle

Perennial

Height

3 ft 3 in to 7 ft

Spread

20 ft

Hardiness Zones

Zones 6-10

Sunlight Requirements

Ideally full sun.

Soil Type

Well-drained soil

Soil Drainage

Well-drained soil.

Soil pH

5.0-8.0

Bloom Color

White

Bloom Time

Spring and Summer

Foliage Color

Gray-green

Leaf Lifecycle

Deciduous

Growth Rate

Moderate

Seasons of Interest

Spring, Summer, Fall, Winter

Propagation Methods

Seeds, Cuttings, Division

Attracts Wildlife

Likely attracts butterflies

Taxonomy

Taxonomic Rank
Species
Author
Eastw.
Publication
Proc. Calif. Acad. Sci. , ser. 3, 1: 133 (1898)

Superior Taxa

Kingdom
Plantae
Subkingdom
Pteridobiotina
Phylum
Angiosperms
Order
Ranunculales
Family
Papaveraceae
Subfamily
Papaveroideae
Tribe
Papavereae
Genus
Romneya

Synonyms

Romneya coulteri var. trichocalyx

References

Romneya trichocalyx. rareplants.cnps.org.
Bristly Matilija Poppy - Calscape. calscape.org.
Romneya trichocalyx. en.wikipedia.org.
Romneya trichocalyx | International Plant Names In…. ipni.org.
USDA Plants Database. plants.sc.egov.usda.gov.
Romneya trichocalyx Eastw. | Plants of the World O…. powo.science.kew.org.
How to Propagate Romneya trichocalyx - Propagate O…. propagate.one.
Romneya trichocalyx. rareplants.cnps.org.
Romneya tricocalyx - Native Plant Database. theodorepayne.org.
Romneya - Perennial Plant, How to grow - Professio…. backyardgardener.com.
Romneya trichocalyx - Calflora. calflora.org.
Romneya trichocalyx, Matilija Poppy.. laspilitas.com.
World Flora Online. worldfloraonline.org. June 2024.