Hedeoma hispida (Rough False Pennyroyal)

Plant Info
Also known as: Mock Pennyroyal
Family:Lamiaceae (Mint)
Life cycle:annual
Habitat:sun; dry sandy or rocky soil; prairies, along roads, railroads, waste areas, outcrops, gravel pits
Bloom season:May - August
Plant height:3 to 16 inches
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: irregular Flower shape: tubular Cluster type: whorled

[photo of flowers] Flowers are in whorls around the leaf axils in groups of 2 to 12, often with a distinct space between whorls. Individual flowers are blue to purple, about ¼ inch long, tubular with a notched upper lip and 3-lobed lower lip. The calyx is green, tubular, distinctly ribbed and hairy, with sharply pointed teeth.

Leaves and stem: Leaf attachment: opposite Leaf type: simple

[photo of leaves] Leaves are narrow, about ¾ inch long and not more than 1/8 inch wide, toothless, hairy to varying degrees, with a blunt point at the tip, no stalk, and may be crowded on the stem or widely spaced. Stems are square, covered in short hairs, and unbranched or branched near the base.

Fruit: Fruit type: seed without plume

[photo of fruit] The calyx persists and dries to light brown as fruit matures. Fruit is a 1-seeded nutlet.


Rough False Pennyroyal is a small plant with tiny flowers that can easily be overlooked. I have often found it growing in open prairie areas on the sandy mounds left by pocket gophers.

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More photos

Photos by K. Chayka taken at Gneiss Outcrops SNA, Chippewa County, Wild River State Park, Chisago County, and in Ramsey County. Other Photos courtesy Peter M. Dziuk.


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Todd - Waseca
on: 2009-08-04 21:14:29

This is growing fairly pervasively throughout my horses' dry lot, and I was concerned that it may be toxic, so I've been trying to find out what it is. Sure enough, it's Rough False Pennyroyal. Makes a nice groundcover ;)

Posted by: Steve - Lost Valley Prairie SNA
on: 2014-07-10 19:57:18

This is a common plant at Lost Valley but very easy to overlook. It is very small and seems to grow only in the thinnest of soil or in rock cracks on the top of the prairie knobs. Although it blooms early in the year, it is still easy to recognize anytime because of its distinct shape and habit of growing where virtually nothing else will. Fun little plant. How can it live and still be so small and compact.

Posted by: Brett - Sand Dunes State Forest Area
on: 2020-06-27 16:29:19

Was blooming today here in Uncas Dunes SNA. I always notice it and think Hey thats that Penny plant but never remember the real name :)

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