When does Romneya coulteri bloom?

Romneya coulteri generally flowers from May through August, with the heaviest bloom in early to midsummer.

What pollinators visit Romneya coulteri?

The large white flowers of Romneya coulteri attract bees and beetles, which move between the blooms to collect pollen from the prominent yellow centers.

How much water does Romneya coulteri need?

This shrub is adapted to dry, well drained soils and performs best with low supplemental water once it is established, especially in chaparral and coastal sage scrub type gardens.

How much sun does Romneya coulteri require?

Romneya coulteri grows best in full sun and can tolerate part sun in hotter inland gardens, but flowering usually declines in shadier spots.

Does Romneya coulteri die back in winter?

In colder or drier conditions the stems can die back to the base after bloom, while in milder coastal climates it tends to stay semi-evergreen with less dieback.

Is California Tree-poppy HOA-friendly?

California Tree-poppy is generally an HOA-friendly choice in the right placement, with moderate maintenance.

California Tree-poppy

Name: Pollinator Patch
Author: Pollinator Patch

Romneya coulteri

Last reviewed: August 2026

Romneya coulteri, the California tree poppy, is a large drought tolerant shrub that produces big white poppy like flowers with golden centers from late spring through summer, typically May to August.

California Tree-poppy (Romneya coulteri) is not on the ASPCA Animal Poison Control Center toxic plant list for dogs or cats (aspca.org (opens in new tab), last reviewed 2026-05-21). If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.

Light

full sun

Water

low

Size

48"–96" H × 36"–72" W

Bloom

May, Jun, Jul, Aug

Native to

Pollinators

bees, beetles

Before you buy

Your city may pay you to plant this

Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.

Find rebates in your area

Browse plants for this ecoregion

Central California Foothills and Coastal Mountains Southern California/Northern Baja Coast

A large shrub with striking white flowers that can reach 6 inches across with bright yellow centers. It blooms throughout summer with papery petals and creates a dramatic focal point in the landscape. This drought-tolerant native plant has blue-green foliage that provides a pleasing contrast to its showy flowers.

Growing California Tree-poppy

Grow California Tree-poppy in full sun and low water. Mature plants reach 48 to 96 inches tall and spread 36 to 72 inches wide. Expect moderate maintenance to keep it looking intentional in a front yard.

In an HOA neighborhood

California Tree-poppy is an HOA-friendly choice in the right placement. Maintenance level: moderate. Tidiness: 2 out of 5.

Works well in: mid zone, backyard only.

Spreads aggressively via underground runners
Can look somewhat messy after blooming
Deciduous habit leaves bare patches in winter

Wildlife value

The large, showy flowers attract numerous native bees and beetles, providing important pollinator support during summer months. The abundant pollen is a valuable food source for beneficial insects.

Common questions

When does Romneya coulteri bloom?: Romneya coulteri generally flowers from May through August, with the heaviest bloom in early to midsummer.
What pollinators visit Romneya coulteri?: The large white flowers of Romneya coulteri attract bees and beetles, which move between the blooms to collect pollen from the prominent yellow centers.
How much water does Romneya coulteri need?: This shrub is adapted to dry, well drained soils and performs best with low supplemental water once it is established, especially in chaparral and coastal sage scrub type gardens.
How much sun does Romneya coulteri require?: Romneya coulteri grows best in full sun and can tolerate part sun in hotter inland gardens, but flowering usually declines in shadier spots.
Does Romneya coulteri die back in winter?: In colder or drier conditions the stems can die back to the base after bloom, while in milder coastal climates it tends to stay semi-evergreen with less dieback.
Is California Tree-poppy toxic to dogs?: California Tree-poppy is not on the ASPCA Animal Poison Control Center toxic plant list for dogs (aspca.org).
Is California Tree-poppy toxic to cats?: California Tree-poppy is not on the ASPCA Animal Poison Control Center toxic plant list for cats (aspca.org).
Is California Tree-poppy HOA-friendly?: California Tree-poppy is generally an HOA-friendly choice in the right placement, with moderate maintenance.

These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.

Native range data from vouchered herbarium specimen records and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

If something looks wrong

Common plant problems, and what to check first

These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.

See all plant problem guides

Ready to grow California Tree-poppy? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

Add this plant to your garden

iPhone app Android app

Planning a bed around it? Start a free plan with this plant

Not sure where to start? Take the 2-minute yard quiz