Scarlet Monkeyflower (Erythranthe cardinalis) - red flowers, illustrated plant cardIllustration

Scarlet Monkeyflower

Erythranthe cardinalis

Also called cardinal monkey flower

Scarlet Monkeyflower blooms from June through October.

Bloom calendar
Bloom time
Jun–Oct
checked
Hardiness
Zones 7–10
checked
Sun
Part shade
checked
Water
High water
checked
Mature size
2 ft × 2.5 ft
checked
Type
Perennial
house classification

Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.

Growing Scarlet Monkeyflower

Plant it in part shade. It prefers high water. It is hardy in USDA zones 7–10. Expect it to reach about 2 ft tall and 2.5 ft wide at maturity, in roughly 2 years (a house reading).

Pets

  • Not yet checked for pets.

Lists differ and none is complete. If a pet eats a plant and seems unwell, call a veterinarian or a pet poison helpline.

No toxicity note is on file for Scarlet Monkeyflower. That is not a clearance: check its safety for people and pets before planting.

Verification
What was checked

Nine facts were checked against named botanical sources, each recorded beside the sources that carried it: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Soil, diseases, pests, toxicity and the plant's own names have not yet been read for this plant, and its trait tags are the ones a feature uses rather than every word a page prints. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.

See the 8 sources it was checked against

When to plant Scarlet Monkeyflower

Plant Scarlet Monkeyflower in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 8, the middle of its hardy zones 7 to 10, spring means February to April and fall means September or October. Once settled, it blooms from June to October.

Month-by-month timing for your zone is on the planting calendar; if you garden near zone 8, the middle of this plant's hardy range, start with zone 8 in February. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.

How big does Scarlet Monkeyflower get?

Illustration of Scarlet Monkeyflower drawn to scale beside an adult2 fttall5 ft 7 inan adult2.5 ftwide
About 2 ft tall and 2.5 ft wide at maturity: knee-high beside an adult.

See Scarlet Monkeyflower in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.

How far apart to plant Scarlet Monkeyflower

Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.

Space Scarlet Monkeyflower about 2.5 ft apart, center to center, so each plant has room to reach its full width.

Plant them
2.5 ft apart
Per 10 sq ft
about 2
4 by 8 ft bed
about 3

Add Scarlet Monkeyflower to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.

Where these facts come from

Scarlet Monkeyflower's height, spread, hardiness zones, sun, water, bloom months and color and trait tags were checked against 8 published sources on November 5, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.

  • Missouri Botanical Gardenheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
  • sacvalleycnps.orgSacramento Valley Chapter, California Native Plant Societyheight, sun, water, bloom months and color and trait tags
  • calfloranursery.comCalifornia Flora Nurseryheight, spread, water and bloom months and color
  • store.theodorepayne.orgTheodore Payne Foundationheight, spread, water and bloom months and color
  • marionswcd.netMarion Soil and Water Conservation Districtheight, water and bloom months and color
  • greenseedgardens.comGreen Seed Gardensheight, spread and hardiness zones
  • RHSRoyal Horticultural Societysun and bloom months and color
  • csuci.eduCalifornia State University Channel Islandswater

How the checking works, and what each standard covers, is on the verified plants page.

Where it grows wild

Native to 6 states

United States: Arizona, California, Nevada, Oregon, Utah, Washington

Recorded growing wild in 68 counties.

Range data from the World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 4.0, adapted) and USDA PLANTS. How the native range is credited.

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Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.

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