No. 12
Plant of the month: March
Cleavers
Galium aparine
Leaves & tender stems young shoots and leaves (cooked, or very young tips raw); seeds roasted as a coffee substitute
Drawing: Britton & Brown, Illustrated Flora (1913)
- Find
- Everywhere
- Effort
- Quick kitchen prep
- ID risk
- Beginner
- Origin
- native
- Uses
- Eat raw / salad
- Cooked vegetable / soup
- Coffee substitute
Season
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
in season peak
What these mean
Find
1 Everywhere · 2 Common in the right habitat · 3 Patchy · 4 Elusive. This is about how much there is, not whether you may pick it. It is based on iNaturalist sightings within 25 km (about 15 miles) of downtown DC, counted on October 3, 2026. The four rules that each plant’s “Find” reason refers to: (A) the estimate is the confirmed sightings, plus the unconfirmed ones (scaled down where the plant has lookalikes in its genus), plus the sightings marked as planted; (B) the tier by estimate: 1,500 or more is tier 1, 250–1,499 tier 2, 50–249 tier 3, under 50 tier 4; (C) tier 1, Everywhere, also needs a source saying the plant is common in lawns, sidewalks, yards or gardens, vacant lots or towns, or at least one DC street tree of it per km of sidewalk, otherwise it is tier 2; (D) if a reliable source says the plant is rare in this region, or that wild plants rarely bear the harvest, only planted sightings count. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.
Effort
1 Grab & eat · 2 Quick kitchen prep (under about 30 minutes) · 3 Real work (hours, or cooking needed for safety) · 4 Project (days or equipment). Scored on the simplest worthwhile use; each plant’s page says why.
ID risk
How hard it is to harvest safely. Beginner: no dangerous lookalike, and the edible part is not easily confused with a toxic part. Careful: a toxic lookalike, or toxic parts that end up in the harvest unless removed (for example elderberry stems, unripe ground cherries), or other parts of the plant rated medium-or-higher toxicity, with reliable features to separate them. Expert only: a potentially deadly lookalike that is hard to separate, or (for not-recommended harvests like pokeweed) a plant whose safe preparation can’t be guaranteed. Toxic parts that are obviously separate and thrown away anyway (pits, seeds, skins) don’t raise it; the Toxic parts mark carries that warning.
Native or not, and the invader stars
Origin is where the plant comes from: native, non-native, or mixed (the harvest covers both). The stars rate plants on invasive plant lists: ★★★ Virginia DCR “High” or Maryland prohibited invasive · ★★ Virginia “Medium” · ★ Virginia “Low” · ☆ listed only by the Maryland Invasive Species Council or the Mid-Atlantic Plant Invaders guide (advisory) · no stars: native or not listed.
Seasons
Start, peak and end are given in thirds of a month: early, mid or late. A plant counts as in season for a month if it is in season at any point in that month. Some greens and roots have a second window, in spring or fall; their page shows each window. A season that runs across New Year is shown as one window.
What it looks like
A sprawling annual whose weak square stems and narrow leaves in whorls of 6-8 are covered in tiny hooked bristles that make it stick to clothing. Tiny white four-petaled flowers in spring give way to small bristly burr-like fruits. Young leaves are eaten raw or cooked.
Safety
No toxicity noted in sources. The hooked bristles can irritate sensitive skin (Penn State); use only very young tips raw (Penn State; MDC), and cook older shoots.
Safety flags
Handling hazard (minor)
thorns/prickles: The scratchy, hooked bristles (tiny prickles) can irritate people with sensitive skin (Penn State).
- Galium aparine (Cleavers) NC State Extension Gardener Plant Toolbox
- Getting the Best of Catchweed Bedstraw (Apr 28, 2026) Penn State Extension
Safety marks and flags: what this means
Deadly lookalike / Toxic lookalike: a cited source names a lookalike of that danger. Deadly means a source says eating it may be fatal or calls it deadly, or NC State rates it high severity with life-threatening symptoms (sources sometimes disagree; for example Virginia creeper). Each plant’s Lookalikes list says how to tell them apart; “harmless (may be edible)” lookalikes are listed so you know a mix-up isn’t dangerous. Cook first: cooking is needed for safety (for daylilies it is a precaution, not a sourced requirement). Eat in moderation: a source says to limit quantity or frequency (for example oxalates in sorrels and dock, ginkgotoxin, safrole). Spray risk: a source says the plant is commonly treated with herbicide in parks or lawns (invasive control, lawn weeds) or, for ginkgo, sprayed to stop fruiting. Contamination: a source says the plant concentrates pollutants. Each plant’s Safety flags list gives the details and sources.
- ID risk
- Beginner
- Why
- No toxic lookalike is named; the clinging hooked bristles are distinctive.
- Handling hazards
- Thorns (minor)
- Soil risk
- higher
ID risk: what this means
How hard it is to harvest safely. Beginner: no dangerous lookalike, and the edible part is not easily confused with a toxic part. Careful: a toxic lookalike, or toxic parts that end up in the harvest unless removed (for example elderberry stems, unripe ground cherries), or other parts of the plant rated medium-or-higher toxicity, with reliable features to separate them. Expert only: a potentially deadly lookalike that is hard to separate, or (for not-recommended harvests like pokeweed) a plant whose safe preparation can’t be guaranteed. Toxic parts that are obviously separate and thrown away anyway (pits, seeds, skins) don’t raise it; the Toxic parts mark carries that warning.
Handling hazards: what this means
Stings, thorns, irritating or phototoxic sap, staining hulls and spiny husks, with a severity: minor = brief discomfort; moderate = rash or blisters lasting days; serious = burns, scarring or medical care possible.
Soil risk: what this means
Based on the part you eat, following the urban-soil lead guidance on the Field safety page: higher for greens, shoots and roots; moderate for flowers; low for fruit, nuts and sap.
Field safety for every outing (poison ivy, ticks, soil, and more)
When to pick
- Starts
- late Feb
- Peak
- late Mar–late Mar
- Ends
- mid Apr
Pick young, tender tips before flowering. Around DC cleavers comes up in numbers from late February and starts flowering in mid-April (iNaturalist; Lady Bird Johnson Wildflower Center gives April bloom); afterwards the plants get stringy and burry. The seeds for roasting form from late April into June (iNaturalist). Penn State Extension notes a second flush of seedlings in late summer and fall.
How the dates were worked out
Every start, peak and end was re-checked in October 2026. “Sourced” means a source opened during the check states that timing for the DC or Mid-Atlantic area. “Estimated” means no source states it exactly; the reason, the evidence and the source links are under “How the dates were worked out” on each plant’s page. Peaks are often estimated, because few sources name a peak. iNaturalist evidence means research-grade sightings near DC, by month, of the plant at that stage (for example, in fruit). iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.
Season basis: sourced
Start
sourced
Peak
sourced
End
sourced
Evidence
start: iNaturalist DC cleavers records by third of the month (days 1-10, 11-20, 21-end): February 1/3/10, March 29/50/56 (common from late February). | peak: iNaturalist DC obs rise through weeks 12-14 (29, 45, 66) while flowering obs are still near zero (weeks 13-14: 2 each). | end: iNaturalist DC flowering obs by week: 15:12, 16:23, 17:125 (flowering from about Apr 9-15). Lady Bird Johnson: blooms April.
- api.inaturalist.org/v1/observations/histogram
- api.inaturalist.org/v1/observations/histogram
- Cleavers research-grade observations within 25 km of DC, by week (flowering annotation) iNaturalist
- Galium aparine (Stickywilly) Lady Bird Johnson Wildflower Center, Native Plant Database
Where to look
Sprawling over shrubs on floodplain and woods edges (Rock Creek Park, Four Mile Run, the C&O towpath, all no-picking), and a weed of shady landscape beds in home gardens (Penn State); pick from your own beds, hedges and private woodlots with permission.
- Habitats
- disturbed ground & waste places, old fields & meadows, woods edges, trailsides & thickets, floodplain & stream-valley forest
Habitats: what this means
Listed where the plant’s own sources place it in that habitat. “Disturbed ground & waste places” means a cited source places it on disturbed areas, sites, soil or ground, on waste places or waste ground, on construction or abandoned building sites (old home sites count), on rubble or in strip mines. When the source gives examples of the disturbed places, at least one example must be of that kind. Examples that do not count: natural or forestry disturbance (treefall gaps, fire, windthrow, flood scour, old riverbanks and creeks, clear-cuts); roadsides, railroads and rights-of-way; and abandoned fields, pastures and farmland, which are “Old fields & meadows”. “Vacant lots” only where a source says vacant or empty lots.
Most-logged places
None of the most-logged places allows picking.
No picking here (5 places)
- Rock Creek Park
Look but don’t pick: Rock Creek Park’s compendium bans gathering any fruit, nut, berry, seed or greenery.
- C&O Canal NHP (towpath, Georgetown to Great Falls MD and beyond)
Look but don’t pick: the C&O Canal compendium covers only edible fruits, nuts, berries and mushrooms, and NPS parks can never designate leaves, flowers, roots or sap. Of these, 13 are at Carderock.
- Huntley Meadows Park
Look but don’t pick: Fairfax County parks ban removing any plant part without written permission.
- Four Mile Run stream valley (Arlington/Alexandria)
Look but don’t pick: Arlington County park rules (flora shall not be removed or disturbed) and Alexandria’s permit rule both apply.
- Glencarlyn Park
Look but don’t pick: Arlington County park rules say flora shall not be removed or disturbed.
Most-logged places: what this means
The places with the most research-grade iNaturalist sightings within 25 km of downtown DC (re-counted in October 2026 over every named place, campuses, condominiums and private grounds included), each marked legal to pick or not. A sighting inside several named places counts once, for the smallest of them, but a sighting inside a National Park Service park never counts for a private, campus or unchecked place. iNaturalist shows where people walk and log plants, not true abundance. Private campuses, condominiums, museums, estates and utility land (Pepco’s power-line land near Sligo Creek) are marked “no” (pick only with the owner’s permission); public university campuses, city parks and other places whose picking rules were not checked (county stormwater land, the U.S. Capitol Grounds, Greenbelt’s North Woods, federal facilities such as the National Zoo) are “unknown”. A place needs at least 2 sightings, so plants with very few sightings (rugosa rose) have no places. No most-logged places are named for at-risk plants (ramps, chinquapin, American chestnut); chinquapin’s page names Mason Neck State Park, where picking is legal, and asks you to leave most nuts. For some places, mostly Rock Creek Park, the iNaturalist map shows more sightings than the count here, because a map link cannot leave out exactly the sightings credited to another place. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.
Where you may pick
On National Park Service land around DC (Rock Creek Park and other NPS units) gathering leaves, flowers, roots or other non-fruit plant parts is prohibited, because 36 CFR 2.1(c) lets a park designate only fruits, berries and nuts; Rock Creek’s compendium also bars gathering fruits, nuts, berries, seeds, mushrooms or cut greenery. Get permission before picking in county or regional parks or on private land.
- (no listed park)
Private land with the owner’s permission only
Where you may pick: what this means
For each park system: “yes” where its current rules (the park’s compendium or regulation) allow this plant or part, with the limit; “ambiguous” where the wording may or may not cover it, so ask the park; “no” where it is not allowed. Rock Creek Park, the GW Parkway sites (including Great Falls VA and Theodore Roosevelt Island), the National Mall, Montgomery and Prince George’s parks, Maryland state parks, and Fairfax and Arlington parks prohibit picking. Wolf Trap National Park for the Performing Arts allows blackberries and raspberries (one gallon per person per day) and chestnuts (one gallon per person per day). National Park Service rules are reissued every year; other parks change theirs from time to time, so check the park’s current rules. The Where you may pick page has every park’s rules.
Ways to use it
- cooked as a potherb
- very young tips in salads
- roasted seeds as a coffee substitute
Keeping
Use within a day or two; blanch and freeze extras for cooking.
- Use within
- within a few days
- Keeps fresh
- A day or two refrigerated in a bag (general guidance for tender greens).
- Keeping basis
- general guidance for its type
Ways to keep it
Freeze as researched: blanch & freeze; canning: n/a (not shelf-canned)
NCHFP: water-blanch 2 minutes (collards 3), cool, drain, pack with 1/2-inch headspace. Frozen greens are for cooked dishes only. Greens are low-acid and may only be pressure-canned, never water-bath canned, so freezing is the practical home method. For the potherb use.
Canning: what this means
Shelf-stable canning, three levels. Lab-tested: a lab-tested recipe from the National Center for Home Food Preservation (NCHFP) or Oregon State covers this fruit and product, or a generic recipe for its kind (the line says so, for example chokeberry). Extension recipe: a published Extension recipe (University of Alaska Fairbanks, written for Alaska species; University of Maine’s dandelion jelly), or a process that is safe only with a pH meter; follow it exactly, never improvise. No tested recipe: refrigerate or freeze, don’t can. “Hot-bottled syrup” = maple and walnut syrup, which keep when bottled hot at full syrup density. The Canning line names the exact product each source covers, for example “whole berries” or “juice”; a product not named there (such as juice from a berry with only a whole-berry recipe) has no tested recipe.
Keeping basis: what this means
“Specific to this plant” or “general guidance for its type” (for example NCHFP guidance for leafy greens applied to a wild green).
Nutrition
How much of a day’s needs one standard serving (85 g) provides, using the FDA’s daily values and serving sizes. The FDA calls 20% or more “high” and 10–19% a “good source”. Every figure below is listed with its source; where the sources disagree, all of them are shown and no conclusion is drawn.
No nutrient measurements were found of the fresh part you eat.
Figures left out, and why (1 study; 1 with no figure used)
The calendar counts a study with no figure used here when one of its vitamin, mineral or dietary fiber figures was left out as a dried sample, another part, or for an unclear species, part or basis; figures given per amount of juice are not counted.
- Turan 2014 (counted in the calendar): dry or dried basis: per kg of leaf sample as analyzed: dried herbal-shop material, ground; the thesis does not state the basis in words (no moisture given); mean of the three shop samples, ± value as printed (0.182 mg/kg); dry or dried basis: per kg of leaf sample as analyzed: dried herbal-shop material, ground; the thesis does not state the basis in words (no moisture given); mean of the three shop samples, ± value as printed (0.267 mg/kg); dry or dried basis: per kg of leaf sample as analyzed: dried herbal-shop material, ground; the thesis does not state the basis in words (no moisture given); mean of the three shop samples, ± value as printed (0.853 mg/kg); dry or dried basis: per kg of leaf sample as analyzed: dried herbal-shop material, ground; the thesis does not state the basis in words (no moisture given); mean of the three shop samples, ± value as printed (12.547 mg/kg); dry or dried basis: per kg of leaf sample as analyzed: dried herbal-shop material, ground; the thesis does not state the basis in words (no moisture given); mean of the three shop samples, ± value as printed (76.057 mg/kg); dry or dried basis: per kg of leaf sample as analyzed: dried herbal-shop material, ground; the thesis does not state the basis in words (no moisture given); mean of the three shop samples, ± value as printed (86.646 mg/kg); species, part or state not clear: Species named (Galium aparine L., sold as yoğurt otu), but the material is dried medicinal herb bought from herbalists, described only as leaf samples; growth stage unknown; dry state, not the fresh young shoots and leaves the dataset means; no voucher or species check described.
What was searched
- Europe PMC: searched 2026-10-09, 126 records; 85 after removing duplicates across databases; 0 candidates by title and abstract; 0 read in full; 0 with figures used
- PubMed: searched 2026-10-09, 44 records; 44 after removing duplicates across databases; 0 candidates by title and abstract; 0 read in full; 0 with figures used
- OpenAlex: searched 2026-10-09, 569 records; 540 after removing duplicates across databases; 5 candidates by title and abstract; 1 read in full; 1 with figures used
- Crossref: searched 2026-10-09, 121 records; 107 after removing duplicates across databases; 2 candidates by title and abstract; 0 read in full; 0 with figures used
- J-STAGE (Japan): searched 2026-10-09, 81 records; 79 after removing duplicates across databases; 0 candidates by title and abstract; 0 read in full; 0 with figures used
- USDA FoodData Central (online search): searched 2026-10-09, 0 records; 0 after removing duplicates across databases; 0 candidates by title and abstract; 0 read in full; 0 with figures used
- USDA FoodData Central (downloaded SR Legacy 2018 and Foundation 2026 tables): searched 2026-10-09, 0 records; 0 after removing duplicates across databases; 0 candidates by title and abstract; 0 read in full; 0 with figures used
- All databases together: 941 records from all databases, 736 unique, 6 candidates, 1 read, 1 used; 5 not read (paywalled 1, blocked automated access 4, not online 0)
- KCI (Korea), CNKI (China), SciELO (Latin America), CORE, USDA’s AGRICOLA and PubAg, Google Scholar, and national food composition tables other than USDA’s: not searched (October 2026).
The counts are of papers new in this search. Sources found before this search (such as USDA’s entries) were not counted again.
Each database was searched for the plant’s scientific and common names together with nutrient words (composition, nutrient, vitamin, mineral, fiber, protein and others), in titles and abstracts only. Papers that don’t name the plant there, and words not on the list (such as fat, energy and moisture), were missed unless another paper led to them; the AI researchers found some that way.
Found but not read (5)
- Biochemical Profiles, DPPH Radical-Scavenging Activity, and Associated Soil Properties of Wild Galium verum L. and Galium aparine L. Populations in Southeastern Bulgaria M. Petkova, M. Todorova, M. Tzanova, N. Grozeva 2026; not read: the site blocked automated access
- Proximate Composition and Antioxidant Activity of Selected Morphological Parts of Herbs W. Biel, U. Pomietło, R. Witkowicz, E. Piątkowska, A. Kopeć 2023; not read: the site blocked automated access
- Profile of heavy metals in selected medicinal plants Shad Ali Khan, Lajbar Khan, Iqbal Hussain, Khan Bahadar Marwat, Naveed Akhtar (authors as given by a web search result; not seen on the paper) 2008; not read: the site blocked automated access
- Trace metal pollution in soil and wild plants from lead–zinc smelting areas in Huixian County, Northwest China Huiying Zhan, Yu-Feng Jiang, Jian-Mei Yuan, X. Hu, O. D. Nartey, Bei-Lei Wang 2014; not read: paywalled
- Vorläufige Notiz über die Bestandtheile des Krautes von Galium verum und Galium aparine not seen (Crossref lists no author) 1852; not read: the site blocked automated access
Collected in October 2026 by AI research agents, following written rules; the calendar’s figures were then checked independently.
Native or not
USDA PLANTS lists Galium aparine as native in the lower 48; NC State gives its range as North America, northern Asia and Europe.
- Origin
- native
- Native range
- North America (also Eurasia, per NC State)
- Virginia invasive rank
- not listed
- Maryland invasive status
- not listed
Native or not, and the invader stars: what this means
Origin is where the plant comes from: native, non-native, or mixed (the harvest covers both). The stars rate plants on invasive plant lists: ★★★ Virginia DCR “High” or Maryland prohibited invasive · ★★ Virginia “Medium” · ★ Virginia “Low” · ☆ listed only by the Maryland Invasive Species Council or the Mid-Atlantic Plant Invaders guide (advisory) · no stars: native or not listed.
Virginia DCR, Virginia Invasive Plant Species List (effective September 2024), verbatim: "Under the DCR Invasive Species Assessment Protocol, approved by the Virginia Invasive Species Working Group, January 2024, species were ranked as exhibiting high, medium or low levels of invasiveness based on their threat to natural communities and native species. Invasiveness rank is higher for species that: • Alter ecosystem processes, such as succession, hydrology or fire regime. • Are capable of invading undisturbed natural communities. • Cause substantial impacts on rare or vulnerable species or natural communities or high-quality examples of more common communities. • Are found widely distributed and generally abundant where present. • Disperse readily to new areas. • Are difficult to control." The list also states: "The list is for educational purposes only and has no regulatory authority."
Maryland Department of Agriculture, Maryland Prohibited Invasive Plant Law and Regulations page, verbatim: "Plants on the Maryland Prohibited Invasive Plant List may not be added to stock after the effective date and should not be sold after their phase-out period ends."
No official DC invasive plant list was found.
How the ratings were set
- Find
- Everywhere Estimate 1,974 = 1,421 research-grade iNaturalist sightings within 25 km + 738 needs-ID sightings counted at 74% (1,421 of the 1,926 research-grade Galium sightings here are cleavers (the Galium aparine complex)) + 9 'cultivated' (planted) sightings (rule A); that is tier 1 by count (rule B). Rule C (everyday place) is met: Penn State Extension says "In home gardens, it is most often seen in landscape beds and on the edge of wooded areas". Final tier 1.
- Effort
- Quick kitchen prep Chop young shoots finely and cook as a potherb, or add very young tips raw to salads.
Find: what this means
1 Everywhere · 2 Common in the right habitat · 3 Patchy · 4 Elusive. This is about how much there is, not whether you may pick it. It is based on iNaturalist sightings within 25 km (about 15 miles) of downtown DC, counted on October 3, 2026. The four rules that each plant’s “Find” reason refers to: (A) the estimate is the confirmed sightings, plus the unconfirmed ones (scaled down where the plant has lookalikes in its genus), plus the sightings marked as planted; (B) the tier by estimate: 1,500 or more is tier 1, 250–1,499 tier 2, 50–249 tier 3, under 50 tier 4; (C) tier 1, Everywhere, also needs a source saying the plant is common in lawns, sidewalks, yards or gardens, vacant lots or towns, or at least one DC street tree of it per km of sidewalk, otherwise it is tier 2; (D) if a reliable source says the plant is rare in this region, or that wild plants rarely bear the harvest, only planted sightings count. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.
Effort: what this means
1 Grab & eat · 2 Quick kitchen prep (under about 30 minutes) · 3 Real work (hours, or cooking needed for safety) · 4 Project (days or equipment). Scored on the simplest worthwhile use; each plant’s page says why.
Sources
18 sources, each linked to the original.
- Rock Creek Park Superintendent’s Compendium National Park ServiceBacks up: picking rules
- Galium aparine (Stickywilly) Lady Bird Johnson Wildflower Center, Native Plant DatabaseBacks up: description, season, habitat
- Galium aparine (Cleavers) NC State Extension Gardener Plant ToolboxBacks up: description, uses, habitat, native or invasive status
- iNaturalist research-grade observations of Galium aparine complex within 25 km of downtown DC iNaturalistBacks up: findability
- Bulletin #4180, Vegetables and Fruits for Health: Greens University of Maine Cooperative ExtensionBacks up: keeping
- Freezing Greens (Including Spinach) National Center for Home Food Preservation (University of Georgia)Backs up: keeping
- Freezing Pesto National Center for Home Food Preservation (University of Georgia)Backs up: keeping
- Got the Wintertime “Greens”? National Center for Home Food Preservation (University of Georgia)Backs up: keeping
- USDA PLANTS Database: Galium aparine (GAAP2), native status USDA NRCSBacks up: native or invasive status
- Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status
- Maryland Prohibited Invasive Plant Law and Regulations (Maryland Prohibited Invasive Plant List, updated January 2026; additions effective July 15, 2026; 'Next Plants To Be Assessed' 2026-2027) Maryland Department of Agriculture, Plant Protection & Weed ManagementBacks up: native or invasive status
- Non-Native Invasive Terrestrial Plant Species in the State of Maryland (updates approved through the April 18, 2024 MISC meeting) Maryland Invasive Species CouncilBacks up: native or invasive status
- Plant Invaders of Mid-Atlantic Natural Areas, Field Guide (Swearingen & Fulton, 2022; successor to the NPS/USFWS 5th ed., 2017) Mid-Atlantic Invasive Plant Council / Passiflora Press (hosted by Bugwood/Mid-Atlantic Invaders Tool)Backs up: native or invasive status
- Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
- iNaturalist research-grade observations of Galium aparine within 25 km of Washington, DC, by month (all observations, flowering, fruiting) iNaturalistBacks up: season
- Cleavers research-grade observations within 25 km of DC, by week (flowering annotation) iNaturalistBacks up: season
- Wild Edibles of Missouri (Jan Phillips, 2nd ed.) Missouri Department of ConservationBacks up: season, uses
- Getting the Best of Catchweed Bedstraw (Apr 28, 2026) Penn State ExtensionBacks up: season, uses, description, habitat