Dwarf Cinquefoil vs Common Cinquefoil
These two native species are visually similar; both can occur in lawns and on dry, acidic soils. They have numerous subtle differences, but because most traits used to ID them are variable within each species, and have overlap, it is important to check multiple traits. P. canadensis is more tolerant of overhead shade, but less tolerant of ground-level competition, and is more limited to drier, acidic soil. P. simplex ranges farther north, west, and slightly farther south, and requires more sunlight, but is more tolerant of ground-level competition, and also ranges into moister habitats and higher pH soil.
Dwarf Cinquefoil (Potentilla canadensis) | Common Cinquefoil (Potentilla simplex) |
A native, creeping perennial of Eastern North America, occurring on dry to mesic, lightly-shaded sites with acidic soil. | A sprawling perennial native to eastern North America, found on sunny to partly-sunny sites. |
 Terminal leaflets usually have 2-7 leaflets per side. Leaflets are usually only serrated for about 1/2 the length of the leaflet, or slightly more. Photo © Asher P Higgins, CC BY 4.0. |  Terminal leaflets usually have 4-8 teeth per side, rarely up to 13; leaflets average being serrated farther down towards the base of each leaf, only occasionally to 1/2 of the length of the leaflet, usually to 2/3rds 3/4 of the length or even more. Photo © Tom Scavo, CC BY 4.0. |
 Plants bloom slightly earlier on average; leaves on the stem are often not fully-grown and unfurled by the time plants start blooming. Photo © Mac Post, CC BY 4.0. |  Plants bloom slightly later on average; leaves on the stem are usually full-grown and unfurled when plants start flowering. Photo © Tom Scavo, CC BY 4.0. |
 Leaflets tend to have their widest point closer to the tip of the leaflet, and are usually more blunt-tipped. Photo © Koby Yen, CC BY 4.0. |  Leaflets tend to have their widest point farther back, closer to the middle of the leaflet or even closer to the base, and taper more to a sharper tip. Photo © botany08, CC BY 4.0. |
 Growth habit is closer to the ground: stems grow upright only for a short time and then usually sprawl along the ground. Photo © Shelby Lyn Sanders, CC BY 4.0. |  Growth habit is more upright: stems initially grow upright for a longer distance, and then usually arch above the ground, draping over competing vegetation. Photo © Daniel Patterson, CC BY 4.0. |
 Leaflets average shorter (1-4cm) and wider relative to their length. Flowers usually look larger relative to the leaves. Photo © Andrew Conboy, CC BY 4.0. |  Leaflets average longer (1.5-5cm) and narrower relative to their length. Flowers usually look smaller relative to the leaves. Photo © Natalie Waddell-Rutter, CC BY 4.0. |
 Epicalyx bracts (leaflike structures under each flower, lined up with each petal) are about the same length as, or shorter than the sepals (leaflike structures underneath the petals, alternating with each petal). Photo © jamie, CC BY 4.0. |  Epicalyx bracts are often longer than the sepals. Photo © Christopher Volker, CC BY 4.0. |
 Leaflets are more likely to overlap, especially at their bases. Photo © Alicia Ballard, CC BY 4.0. |  Leaflets tend to have more space between them. Photo © Tom Pollard, CC BY 4.0. |
 Prefers more shade from overhead trees, but not as tolerant of ground-level competition. More restricted to dry habitats and acidic soils. Photo © Ben Mowbray, CC BY 4.0. |  Prefers sunnier habitats with less shade from trees, but more tolerant of ground-level competition. Found in a wider range of moisture and soil pH conditions. Photo © Tom Scavo, CC BY 4.0. |
Additional Notes
Of these two species, P. simplex is more of a generalist, which is part of why it has a broader range. The differences in the two species' morphology reflects adaptations to different habitats.The broader leaves, with less space between leaflets, helps P. canadensis to grow in lower-light conditions. Both because of exposure to less sunlight and growing closer to the ground, it is less exposed to wind, and thus has less need to reduce wind drag on its leaves.
The more upright growth habit of P. simplex on the other hand makes it more competitive against ground-level vegetation, but also exposes leaves to more wind. The narrower leaflets with more space between them helps to reduce wind drag and thus water loss. The reduced light capture is less of an issue to this species because it grows in sunnier habitats and is able to grow more upright to capture more light.
The degree to which serrations extend towards the base of each leaflet is one of the most-frequently-cited characteristics used to distinguish these species. It is, however, a highly variable trait on both species, and you can find examples, such as this colony of P. canadensis in VT that are an exception to this rule.
The habitat differences are only average tendencies and there is significant overlap. For example, this colony of P. simplex in MO is growing in conditions that, at least superficially, appear more typical for P. canadensis.
Both of these species can also be confused with European cinquefoil (Potentilla reptans), but that species is usually easier to tell apart from these two than these two are from each other, because P. reptans has larger flowers, more rounded teeth on leaf margins, and usually occurs only on more fertile soils.
References & External Resources
These short lists show only links helpful for ID. For a complete list of references and resources also covering other aspects of ecology, visit the links section of the full article on each plant, which is the first entry here.
