Garden PlannerEvidence-aware. Garden with confidence.
Entire healthy mature rhubarb plant in a real garden bed, showing growth habit and scale.Primary identification image. 60–90 cm tall, 90–120 cm wide at maturity.

Rhubarb

Rheum × hybridum Murray

Also called: Rheum rhabarbarum

Family
Polygonaceae
Season
Perennial hardy perennial (10+ years)
Best grown in
Portland, Oregon

A huge, permanent perennial harvested in spring; its leaves are toxic and its footprint is a square metre.

Safety: Leaves are toxic (oxalic acid and anthraquinones); eat stalks only.

Add to plan View companions Calendar

Life cycle & growth stages

  1. 1. CrownPlant with buds just at the surface.
  2. 2. Year 1No harvest; let leaves grow.
  3. 3. Spring stalksStalks emerge in early spring from year 2.
  4. 4. HarvestPull stalks until midsummer.
  5. 5. RebuildLeave the plant to grow; remove flower stems.
  6. 6. DormancyDies back in winter; mulch.

Growth stages are ordered chronologically; timing varies with cultivar, temperature, light and care.

Planting calendar for Portland, Oregon

transplant 0–6 weeks before last frost; 365–730 days to maturity from planting. Windows are derived from the region's average frost dates (last Apr 5, first Nov 5) and are estimates until you confirm your own dates in the calendar.

RhubarbRheum × hybridum
PlantStart indoorsDirect sowAutumn sowTransplantTendHarvest
Rhubarb———Feb 22–Apr 5 (estimate)Apr 5–Feb 22 (estimate)Feb 22–May 31 (estimate)
  • Transplant outdoors: Feb 22 – Apr 5
  • Tend and monitor: Apr 5 – Feb 22
  • Harvest: Feb 22 – May 31

Spacing & support

In-row 90–120 cm; rows 120–120 cm. Planner footprint: 9 cells of 30 cm.

Side-profile diagram of mature rhubarb: canopy 60–90 cm tall, 90–120 cm wide, deep root zone, support and harvest-access envelope.

Soil & water

Soil
Deep, rich, moisture-retentive soil
pH
6–6.8
Fertility
high
Water
Water in dry spells; mulch heavily.
Frost
very hardy; tolerates frost

Support & training

No support structure needed.

Rhubarb mid-season before harvest, showing branching, vining, rosette or upright habit and space occupied.

Harvest signs

  • Stalks 30 cm or longer
  • Pull and twist from the base; never cut
  • Stop in midsummer
Rhubarb at harvest readiness, showing the visual cues: stalks 30 cm or longer; pull and twist from the base; never cut.

Common problems

Pests: slugs, snails

Diseases: crown rot, honey fungus

Appearance alone is not a diagnosis; confirm with a regional extension guide.

Side-by-side: healthy rhubarb leaf or fruit and an example of crown rot.

Container growing

Too large and long-lived for containers.

Companion overview

2 reviewed relationship records (evidence: low).

Supported or conditional

None reviewed

Avoid or separate

None with evidence

Traditional claims only: Cabbage.

1 popular pairing reviewed with no verified relationship.

Full companion profile

Crop rotation

Rhubarb is a permanent planting; rotation does not apply, but do not replant it where a related crop failed from soil disease.

Crop rotation hub

Sources, reviewer & update

Sources

Reviewer: Garden Planner editorial team (pending independent horticultural review)

Last reviewed: August 15, 2026 · version 1

Found an error or have feedback? Let us know.

Growing rhubarb

Rhubarb is planted as a crown in late winter or early spring into deeply manured soil and left alone for its first year. From the second year, pull stalks from spring until midsummer, then let the plant rebuild. Crowns last a decade or more and can be divided in winter.

Rhubarb planting material (crown, set, clove, slip or tuber) beside a ruler or coin for scale.
Rhubarb seedling at cotyledon and first-true-leaf stage, in soil, distinguishable from common weeds.
Rhubarb at transplant-ready stage with root ball visible beside the cell or pot.

A mature plant covers a square metre with leaves 60–90 cm tall, shading anything beneath. It needs water in dry summers and a thick mulch of compost each winter. Leaves are poisonous and go on the compost heap, not the table.

Two or more mature rhubarb plants with a tape measure showing in-row spacing (90–120 cm).
Rhubarb flower detail or bolting stage.
Immature leaf stalks of rhubarb developing on the plant.

Edible parts and safety

Edible: leaf stalks. Leaves are toxic (oxalic acid and anthraquinones); eat stalks only.

Hands or tool harvesting rhubarb correctly (cut, pull, twist or pick) without damaging the plant.

Pests and diseases

Common pests: slugs, snails. Common diseases: crown rot, honey fungus. These vary by region; a photograph is an example, not a diagnosis. See the pest and disease guides and your local extension service.

slugs on rhubarb, with a wider damage-context view.

Timeline

Season timeline for rhubarb: sowing, transplanting, flowering, harvest and bed occupancy aligned to frost dates.Text alternative: Transplant outdoors Feb 22–Apr 5; Tend and monitor Apr 5–Feb 22; Harvest Feb 22–May 31.

Related plants

See also: Polygonaceae family page · crop rotation · regional calendar · guides

Our Methodology & Sources

We synthesize peer-reviewed research, university extension publications, and trusted horticulture resources. Our evidence levels help you understand how strong the science is behind the guidance.

Evidence tiers

Supported evidenceConsistent results from multiple robust studies
Traditional claimHistorical use reported, limited scientific support
Context dependentMixed or variable results across conditions
No verified relationshipNo reliable evidence identified

Primary source types

  • Peer-reviewed journal articles
  • University extension publications
  • Government & research institute reports
  • Systematic reviews & meta-analyses

Last updated

August 24, 2026

Learn more about our approach