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iNaturalist — CC, credited & licensed per image
Boraginaceae family

Prickly Comfrey Symphytum asperum

Prickly Comfrey is an introduced perennial herb, found in Alaska, Canada, and the lower 48 states. It grows to 5 ft and blooms Jun – Jul.

⚠ Invasive here — plant a native instead USDA + GBIF

Prickly Comfrey is flagged invasive in the U.S. These natives fill a similar niche — same growth habit, bloom season, height, and region — so you keep the look and feed local wildlife instead of spreading a problem.

Prairie Sunflower
Native
Prairie Sunflower
Helianthus petiolaris
●●●●●
Canada Lettuce
Native
Canada Lettuce
Lactuca canadensis
●●●○○
Common Milkweed
Native ★
Common Milkweed
Asclepias syriaca
●●●●●
Spiny Amaranth
Native
Spiny Amaranth
Amaranthus spinosus
●●○○○
Matched on growth habit · bloom months · mature height · shared U.S. range (USDA + GBIF) — a starting point, not a prescription.

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Hardiness
≥ zone 5 derived from its U.S. range
Size & form
Sources · Size & form
TRY Plant Trait Database (CC BY 4.0) — Height · Foliage
USDA PLANTS — Lifespan
McKenzie et al. 2025 — community-science image analysis (MIT) — Flower colour
Height
5 ft
Lifespan
Perennial
Foliage
Broadleaf
Flower colour
Blue AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
In the garden
Shrub layer — Sits in the shrub of a layered food forest or polyculture.Open guide →
derived roles
AI = read by an AI vision model · DERIVED = a computed estimate, not a direct measurement. The “How we know this” section below details each.
The garden year bloom → fruit → fall colour
J
F
M
A
M
J
J
A
S
O
N
D
Bloom
Bloom (the flower's colour)
Bloom · Jun – Jul — 22 obs · Herbarium specimens — Park et al. 2023 (CC BY 4.0)
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.

Wildlife & pollinators

How pollinator value is scored →
❧ Caterpillar hosts ~4 caterpillar species

Symphytum supports ~4 caterpillar species.

Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a modest genus for introduced plants — native genera typically support far more.

Recorded feeding on Symphytum in North America, including:

Acleris schalleriana · leafroller moth Endothenia nubilana · leafroller moth Endothenia quadrimaculana · leafroller moth Lacinipolia renigera · Bristly Cutworm
Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
✦ Bees 33 bee visitors
Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) · GloBI →
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
How we know this (2) Methods & honest limits
Photosynthesis Direct fact

A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.

Kattge, J. et al. TRY plant trait database — Categorical Traits Dataset (2012).
Flower colour Derived

McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.

Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.

McKenzie, P., Berardi, A.E., Hopkins, R. (2025). flower_color_phenology (MIT).
Derived values are computed from open data by a published method — labelled, cited, and never shown as a direct observation. Full methodology →
Sources for this entry (21) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — US-RIIS v2.0 (USGS)
[06] Wetland indicator — USACE National Wetland Plant List (2022)
[08] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[12] Functional traits — TRY Plant Trait Database (CC BY 4.0)
[13] Photosynthetic pathway — TRY Plant Trait Database (CC BY 4.0)
[14] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[18] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[19] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[20] Caterpillar species — NHM HOSTS (CC0)
[21] County range — GBIF Open Data — open-licensed occurrences (CC0/CC-BY) → county
Spot an error or have a better photo? Every field links to its source, and the whole dataset is open.
Cite this page Open data, please attribute

PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).

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