Japanese Pieris (Pieris japonica) - white flowers, illustrated plant cardIllustration

Japanese Pieris

Pieris japonica

Also called japanese andromeda, lily-of-the-valley bush and lily-of-the-valley shrub

Japanese Pieris blooms from March through April.

Bloom calendar
Bloom time
Mar–Apr
checked
Hardiness
Zones 5–8
checked
Sun
Part shade
checked
Water
Moderate water
checked
Mature size
9.5 ft × 7 ft
checked
Type
Shrub
house classification

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

Growing Japanese Pieris

Plant it in part shade. It prefers moderate water. It is hardy in USDA zones 5–8. Expect it to reach about 9.5 ft tall and 7 ft wide at maturity, in roughly 5 years (a house reading).

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

Verification
What was checked

Mature height and spread, hardiness zones, sun, water, bloom months and color and the trait tags were checked against named botanical sources for this plant, with what the sources could not settle written down; years to mature size rests on a recorded house rule where no publisher states one, and is marked so; its common name and alternate names have not been checked yet. 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 Japanese Pieris

Plant Japanese Pieris 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 6, the middle of its hardy zones 5 to 8, spring means March to May and fall means August or September. Once settled, it blooms from March to April.

Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.

How big does Japanese Pieris get?

Illustration of Japanese Pieris drawn to scale beside an adult9.5 fttall5 ft 7 inan adult7 ftwide
About 9.5 ft tall and 7 ft wide at maturity: half again as tall as an adult.

See Japanese Pieris 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 Japanese Pieris

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

Space Japanese Pieris about 7 ft apart, center to center, so each plant has room to reach its full width.

Plant them
7 ft apart
Per 10 sq ft
one needs about 49 sq ft
4 by 8 ft bed
about 1

Add Japanese Pieris 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

Japanese Pieris' height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 8 published sources on September 23, 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.

  • NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity
  • Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases and pests
  • plantdatabase.uconn.eduUniversity of Connecticut Plant Database (Mark H. Brand)height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases and pests
  • woodyplants.cals.cornell.eduCornell University Woody Plants Databaseheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, pests and toxicity
  • RHSRoyal Horticultural Societyheight, spread, sun, water, bloom months and color, soil, diseases, pests and toxicity
  • Oregon State UniversityLandscape Plantsheight, spread, hardiness zones, sun, bloom months and color, soil and toxicity
  • University of Illinois ExtensionSelecting Shrubs for Your Homeheight, spread, hardiness zones, sun, water, bloom months and color and pests
  • ASPCAToxic and Non-Toxic Plants: Pieristoxicity

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

1 more variety in the Pieris group

Same genus, similar care - pick the one you are growing.

Compare every variety in the Pieris group

Every figure is the variety's own page fact. Tap a name to open it.

VarietyColorBloomsHardinessSunSize (H × W)
Japanesethis pageWhiteMar–AprZones 5–8Part shade9.5 ft × 7 ft
Mountain FireWhiteMar–AprZones 5–8Part shade6.5 ft × 5 ft

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