Calendula plant

Calendula growing profile.

Calendula Companion Plants

What may help, what can compete, and where the evidence is still uncertain.

Calendula Calendula officinalis

Cool-season flower in the daisy family. View plant profile →

Quick answer

No reviewed study supports a specific beneficial companion for calendula yet. 1 traditional pairing is listed separately because the review found no adequate evidence.

Every status below has a direction, mechanism, context and source. "No verified relationship" means we looked and found nothing usable; the planner then evaluates spacing, light, water and timing normally. How we classify evidence →

1 records

Traditional claim (1)

Never a hard rule; may appear as an optional experiment.

Traditional claims are shown separately because repetition across charts is not evidence. They never change a planner score; treat them as optional experiments.

TomatoSolanum lycopersicumTraditionalPest suppression · tomato hornworm, aphids Calendula may affect TomatoSummer · arrangement unspecifiedTier D Review: August 15, 2026
Why?

Claim. Calendula is said to deter tomato hornworm and aphids. No controlled evidence; calendula itself hosts aphids, and its open flowers do feed hoverflies.

Mechanism. Proposed by tradition; not demonstrated in a controlled comparison.

Conditions. Planted together Both plants must be present at the same time.

Applies when. Optional experiment, not a guarantee.

Limitations. Tradition; insectary value is general.

Evidence. Tier D: Traditional knowledge or structured community observations without a controlled comparison. (tradition).

Sources. University of Minnesota Extension 2023

Reviewed August 15, 2026 by Garden Planner editorial team (pending independent horticultural review). Record calendula--tomato--pest_suppression v1. Request a correction.

A realistic garden scene where calendula grows beside a plant with a traditional or unknown relationship.Coexistence in a photograph is not evidence that the plants affect each other.

Example layout for calendula

No supported or conditional relationship specifies a layout. Space calendula at 25–30 cm and plan by light, water and timing.

Side view of calendula (30–60 cm) beside typical companions, showing canopy, support, shade and access.

When these companions overlap

Bed occupancy in Portland, Oregon (estimates). A relationship only matters while both plants are present.

Calendula
Tomato27 wk overlap
Overlap in weeks
Tomato27 weeks

Crop rotation guidance

Rotation is about what occupied the bed in previous seasons and is calculated separately from the live companion relationships above.

Rotate calendula on a 1-year cycle with other daisy family crops (Lettuce, Sunflower, French marigold, Cosmos). Shared risks: lettuce downy mildew, aphids, slugs on lettuce.

Crop rotation hub · Asteraceae family page

Physical and resource fit

No significant light, water, pH or sprawl conflicts with the listed companions at recommended spacing.

Fit checks come from plant attributes and apply even when a pairing has a positive claim.

Community observations (anecdotal)

These reports come from gardeners and are not reviewed evidence. Results vary with soil, climate and practice. Community data never changes an evidence tier or a planner score.

Reports for calendula: 0 (community submissions open in a later phase; drafts are stored only on your device).

Community-submitted photo area (moderated) with context fields: region, season, layout, varieties, outcome.
Record an observation

Evidence summary and sources

Reviewer: Garden Planner editorial team (pending independent horticultural review). Status counts on the Companions A–Z page are derived from these records. Corrections.

Related

Visual evidence on this page

Documentary and illustrated views distinguish identification, measured layout, seasonal overlap, mechanisms, coexistence examples, and community observations. Captions state what each visual can and cannot establish.

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