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Rosaceae family

Blackthorn Prunus spinosa

Early-season nectar — Flowers in a late-winter / early-spring window when few other plants in our catalog bloom — valuable early forage for pollinators (relative to our catalog's bloom coverage).
Also known as: sloe, blackthorn

Blackthorn is an introduced perennial tree, found in Canada and the lower 48 states. It grows to 7 ft and blooms Mar – May.

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Niinemets & Valladares 2006 (CC0) — Drought tolerance · Shade tolerance · Wet-soil tolerance
Hardiness
≥ zone 6 derived from its U.S. range
Drought tolerance
Moderate
Shade tolerance
Low
Wet-soil tolerance
Low waterlogging
Size & form
Sources · Size & form
TRY Plant Trait Database (CC BY 4.0) — Height · Foliage
USDA PLANTS — Lifespan
Height
7 ft
Lifespan
Perennial
Foliage
Deciduous broadleaf
In the garden
Shrub layer — Sits in the shrub of a layered food forest or polyculture.Open guide →
derived roles
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 · Mar – May — 10 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 ~456 caterpillar species · keystone genus

Prunus supports ~456 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 powerhouse genus.

Recorded feeding on Prunus in North America, including:

Acleris variegana · leafroller moth ✦ Coleophora cerasivorella · casebearer moth ✦ Hyalophora cecropia · Cecropia Moth ✦ Orthosia hibisci · Speckled Green Fruitworm Moth ✦ Trachycera suavella · snout moth ✦ Yponomeuta padella · ermine moth ✦
+ 8 more species →
Abagrotis alternata · Greater Red Dart Abagrotis barnesi · owlet moth Abagrotis cupida · Cupid Dart Abagrotis orbis · owlet moth Acerra normalis · owlet moth Acharia stimulea · Saddleback Caterpillar Moth Acleris celiana · leafroller moth Acleris flavivittana · Masked Leafroller
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). ✦ = recorded on this exact species.
✦ Bees 98 bee visitors
Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) · GloBI →
Wildlife & visitors 2 birds · 2 mammals · 20 nectaring

Open records of who else uses Blackthorn — a generalist food-web signal, kept separate from the keystone Ecological Value.

20 adult butterfly & moth species are recorded nectaring at its flowers — the most-recorded:

Vanessa atalanta · Red Admiral Pieris napi · Green-Veined White Iphiclides podalirius · Sail Swallowtail Thecla betulae · Brown Hairstreak Hedya pruniana Polygonia c-album · Comma
Interaction records (observations, not exhaustive) from GloBI → (CC0). Counts are distinct species; names are the most-recorded. Common names from Wikidata (CC0).
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 (3) Methods & honest limits
Leaf build Direct fact

We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.

Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.

Díaz, S. et al. (2022) The global spectrum of plant form and function: enhanced species-level trait dataset. Scientific Data 9:755.
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).
Climate niche (heat tolerance & native rainfall) Derived

We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.

Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.

Realized-niche / climate-envelope approach (Pearson & Dawson 2003; Soberón 2007). Climate: NOAA NCEI nClimDiv county normals (1991–2020).
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 (26) 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)
[07] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[09] Conservation rank — NatureServe Explorer (CC BY)
[12] Functional traits — TRY Plant Trait Database (CC BY 4.0)
[13] Photosynthetic pathway — TRY Plant Trait Database (CC BY 4.0)
[14] Climate niche — Derived — realized climate niche from U.S. county occurrences (GBIF) × NOAA NCEI county climate normals 1991–2020 (public domain)
[15] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[16] Wildlife & visitors — GloBI — Global Biotic Interactions (CC0)
[20] Other common names — Wikidata (CC0)
[21] Stress tolerance — Niinemets & Valladares 2006 (CC0)
[23] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[24] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[25] Caterpillar species — NHM HOSTS (CC0)
[26] 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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