Ilex mucronata (Swamp Holly)

Plant Info
Also known as: Catberry, Mountain Holly
Family:Aquifoliaceae (Holly)
Life cycle:perennial woody
Habitat:part shade, sun; wet peaty or sandy soil; bogs, swamps, wet woods, thickets, swales, shores
Bloom season:May - June
Plant height:3 to 15 feet
Wetland Indicator Status:GP: none MW: OBL NCNE: OBL
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: 4-petals Flower shape: 5-petals

[photo of male flowers] Male and female flowers are usually borne on separate plants (dioecious), occasionally a plant will produce perfect flowers (both male and female parts). All flowers are about ¼ inch across with 4 or 5 pale yellow, narrow, ribbon-like petals. Male flowers have yellow-tipped stamens alternating with the petals.

[photo of female flowers] Female flowers have shorter sterile stamens alternating with the petals and a prominent green ovary capped with a yellowish green stigma in the center. Flowers are single in leaf axils along this year's new branchlets, on slender, hairless stalks up to 1 inch long and emerge with the leaves in spring.

Leaves and stems: Leaf attachment: alternate Leaf attachment: whorl Leaf type: simple

[photo of leaves] Leaves are simple, alternate though may be crowded and appear whorled at branchlet tips, 1 to 2 inches long, up to 1 inch wide, somewhat variable in shape, oblong-elliptic to obovate (widest near the tip), rounded to pointed at the tip often with an abrupt minute point (mucronate), rounded to tapering at the base, on a hairless, green to purplish stalk up to ½ inch long. Edges are toothless except for a few minute teeth at the tip end; surfaces are hairless. New twigs are hairless, purplish brown to reddish with scattered white lenticels (pores), developing flaky gray bark second year.

[photo of older bark] Older bark is thin, gray, smooth to rough with warty horizontal lenticels. Stems are erect, multiple from the base, the larger stems up to 2 inches diameter, and may form thickets from root suckers.

Fruit: Fruit type: berry/drupe

[photo of fruit] Fruit is a bright red, round berry, ¼ to 1/3 inch diameter, containing a few nutlets, and persists through winter.


Swamp Holly, also known as Nemopanthus mucronatus, is an uncommon shrub of wet places and reaches the western fringe of its range in Minnesota. We encountered a few isolated plants in a bog at Boot Lake SNA and had to navigate through an obstacle course of knee-deep trenches and Poison Sumac to reach it (hope you appreciate that!). It is fairly easy to recognize when flowering or fruiting, with long-stalked bright red fruits or pale flowers with ribbon-like petals, single in the leaf axils. When flowers and fruits are absent, the leaves may help distinguish it: 1 to 2 inches long, hairless, toothless or with a few teeth at the tip, often with a minute point at the apex, and the leaf stalk usually purplish. The related Winterberry (Ilex verticillata) has larger, toothed leaves with hairy leaf stalks and small clusters of short-stalked flowers and fruits.

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More photos

Photos courtesy Peter M. Dziuk taken at Boot Lake SNA, Anoka County. Fruiting Ilex mucronata By R. A. Nonenmacher (Own work), via Wikimedia Commons, used under CC BY-SA 4.0


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

Posted by: steve h - at CARLOS AVERY
on: 2017-10-28 14:30:27

HELLO, WEVE SEEN THEM AT CARLOS. just passed the headquarters, weve picked berries from the bushs right there by the ditch. the other spot is neer a pond so it does like water.this was maybe mid to late aug to sept 2017

Posted by: Jalene Eden - Pine County
on: 2021-06-25 09:56:17

I have found several stands of Swamp Holly on our property on the forest edges along the sedge meadow. In some areas of our wetlands Swamp Holly that's growing close to beaver runs usually cut down by the beavers. Interesting is that beavers will take the Swamp Holly but rarely cut the Winterberry.

Posted by: Cal Harth - St. Croix State Park,Pine County
on: 2023-09-25 15:07:54

A few shrubs with fruit are in a small wetland on the entrance road of the park in September 2023. the abundant shrub swamps in the park are likely to contain many more.

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