Table of Contents for Dane County, WI Viburnums
There are eleven species of native or nearly native Dane County, WI viburnums (Viburnum spp.) that can be grown for butterflies and other insects. Viburnums are an important host species for two butterflies, spring azure, and the Baltimore checkerspot in Dane County. These plants are also an important nectar source to all insects visiting your pollinator garden and a food source for birds.
General Information about Native Plant and Pollinator Gardens
When planting a native plant and pollinator garden in Dane County, Wisconsin, you need to ensure that you have a selection of plants that provide blooms at different times of the year. Besides viburnums, other host plants that attract other butterflies and pollinators should be considered. These could include milkweeds (Asclepias spp.) for monarch (Danaus plexippus) and queen (Danaus gilippus) butterflies, spicebush (Lindera benzoin) for the spicebush swallowtail (Papilio troilus), pawpaw (Asimina triloba) for zebra swallowtails (Eurytides marcellus), pipevine (Aristolochia spp.) for pipevine swallowtails (Battus philenor), and passionflower (Passiflora incarnata) for the Gulf fritillary (Agraulis vanillae).
Try to have host plants and nectar plants in each part of the growing season. In addition to the plants, you need to provide a source of water such as a birdbath or water feature, shelter for animals, and nesting locations for birds. Be sure to also include plants of different heights for perching. Resources you can use for more information on butterfly gardening in Dane County, WI include Dane County Extension at the University of Wisconsin-Madison, which has a teaching garden, the Madison Public Library, Plant Dane, and Wild Ones.
Location of Dane County, WI
.
Dane County, Wisconsin is located in the south-central part of the state. The major municipalities in Dane County is the City of Madison.
USDA Plant Hardiness Zones in Dane County, WI
Dane County, Wisconsin is located in Zone 5, both 5a and 5b. When selecting plants in Dane County you will want to get those that can handle temperature as cold as -200F.
Butterflies in Dane County, WI that are Hosted by Viburnums (Viburnum spp.)
Spring Azure (Celastrina ladon)
The Spring Azure is a silvery metallic blue on the upperside and has a silvery underside. Females, unlike the males, have a black margin on the wings. A fully grown adult has a wingspan of 0.87 in (2.2 cm) and 1.38 in (3.5 cm).
The whitish eggs are laid on the flower buds of host plants. Several broods a year, more in the south and less in the north, can produce green colored larvae with brown accents. Note, this species may be in Erie County and is present to the west in Ohio.
Baltimore Checkerspot (Euphydryas phaeton)
The Baltimore Checkerspot is a speckled white, orange, and black butterfly. This butterfly is found in the eastern United States and southern Canada from the mid-west and east. Adults have a wingspan of 1.6 in (4.1 cm) to 2.5 in (6.4 cm).
The eggs of this species are yellow and become a reddish-tan color with age (wildadirondacks.org). The caterpillars are black with orange stripes (Pyle 1981). There is one brood that flies from May to July. This butterfly is so named because the color resembles the crest of Lord Baltimore (Pyle 1981).
List of Viburnums that are Native or Nearly Native in Dane County, Wisconsin
1. Maple-leaf Viburnum (Viburnum acerifolium), a Viburnum for Dry to Moist Well-drained Soils
Maple-leaf viburnum is found rich forests, woodlands, and woodland thickets in dry to moist well-drained soils that are slightly acidic. The plants should get about 4-6 hours of direct sunlight each day. During dry spells, the plants shoud be watered and a layer of mulch should be laid to help suppress weeds.
Suitable companion plants for this species in Dane County, by season can include the following. Spring plants — wild geranium (Geranium maculatum), Virginia bluebells (Mertensia virginica), and shooting star (Dodecantheon media). Summer plants — purple coneflower (Echinacea purpurea), butterfly weed (Asclepias tuberosa), black-eyed susan (Rudbeckia hirta), wild bergamot (Monarda fistulosa), blazing star (Liatris spicata), and rattlesnake master (Eryngium yuccifolium). Autumn plants — New England Aster (Symphyotrichum novae-angliae), goldenrod (Solidago spp.), and aromatic aster (Symphyotrichum oblongifolium).
Facts about Maple-leaf Viburnum
- Native to Wisconsin: Yes, generally throughout (Kartesz 2015)
- Native to Dane County: Yes
- Natural Habitat: Rich forests, woodlands, and woodland thickets that have medium to dry soils.
- Height: 3 ft (0.9 m) to 6 ft (1.8 m)
- Flower Color: cream to white
- Flowering Period: June
- USDA Hardiness Zone: 3-8
Gardening with Maple-leaf Viburnum
In your Dane County, Wisconsin butterfly garden this species requires part-shade or dappled sunlight and dry to moist soils that are well-drained. This plant can handle full sun conditions in a garden setting, but does best in shaded conditions.
2. Southern Arrow-wood (Viburnum dentatum), a Viburnum for Medium to Moist Well-drained Soils
Southern arrow-wood is so named for the straight stems that used to be made into arrows by the Native Americans. This shrub can reach a height of 15 feet and has white flowers in the spring. Soils should be medium to moist and well-drained with a full sun to part shade exposure. In the fall the blue berries are enjoyed by birds. When selecting companion plants be sure to consider the taller height of this species.
Suitable companion plants in for this species in Dane County in the spring include columbine (Aquilegia canadensis), Virginia bluebells (Mertensia virginica), and wild bleeding heart (Dicentra exima). In the summer these can include butterfly weed (Asclepias tuberosa), lance-leaved coreopsis (Coreopsis lanceolata), and yarrow (Achillea millefolium). In the fall, some companion plants can include New England aster (Symphyotrichum novae-angliae), goldenrod (Solidago spp.), and Joe-pye Weed (Eutrochium purpureum).
Facts about Southern Arrow-wood
- Native to Wisconsin: No (Kartesz 2015)
- Native to Dane County: No
- Natural Habitat: Rich forests, woodlands, floodplains, and wetlands
- Height: 5 ft (1.5 m) to 15 ft (4.6 m)
- Flower Color: cream to white
- Flowering Period: March to June
- USDA Hardiness Zone: 2-8
Gardening with Southern Arrow-wood
In your Dane County, Wisconsin butterfly garden, this species requires full sun to part-shade and medium to moist well-drained soils. In a garden situation, it can handle drier soils (Flemer 1984). This shrub has brilliant color in the fall, which gives added value to your garden. Even though this species is not native to Wisconsin, it can live in the plant hardiness zone of Dane County and is native.
3. Squashberry (Viburnum edule), a Viburnum for Medium to Moist Well-drained Soils
Squashberry can reach a height of 12 feet and like the arrow-wood, has white flowers. Soils should be moist and well-drained with a full sun to part shade exposure.
Suitable companion plants for squashberry in Dane County are essentially the same as those mentioned for the previous two species. Adding some spicebush (Lindera benzoin), which hosts the spicebush swallowtail (Papilio troilus), would add a variety of heights to the garden.
Facts about Squashberry
- Native to Wisconsin: Yes, rare in northwest (Kartesz 2015)
- Native to Dane County: No
- Natural Habitat: gravelly woods, pine and aspen woods (Gillet 1954), peaty depressions (Thieret 1964), spruce forests (Raup 1946), and floodplain spruce forests (Raup 1947)
- Height: 2 ft (0.6 m) to 12 ft (3.5 m)
- Flower Color: white
- Flowering Period: May to August
- USDA Hardiness Zone: 3-8
Gardening with Squashberry
In your Dane County, Wisconsin butterfly garden, this species requires full sun to part-shade and moist well-drained soils. In a garden situation, it can handle drier soils.
4. Nanny-Berry (Viburnum lentago), a Viburnum for Medium to Moist Well-drained Soils
Nanny-Berry in the wild grows wooded wet areas and grows from 15 to 18 feet tall. In a garden situation it requires medium to moist soils and full sun to part shade. Companion plants should be chosen to provide a color tapestry and enhance the feeding opportunities provided by this shrub. When selecting companion plants for this species, be mindful of the height that this shrub can reach and try to adjust.
Suitable plants to include with nanny-berry to ensure a maximum diversity of butterflies include asters such as New England aster (Symphyotrichum novae-angliae), smooth aster (Symphyotrichum laeve), aromatic aster (Symphyotrichum oblongifolium), goldenrods such as showy goldenrod (Solidago speciosa) and wrinkle-leaf goldenrod (Solidago rugosa), milkweeds such as butterfly weed (Asclepias tuberosa), common milkweed (Asclepias syriaca), and swamp milkweed (Asclepias incarnata). Nectar plants such as purple coneflower (Echinacea purpurea) and mountain mints (Pycnanthemum spp.) can also be included.
observed in Canada by Andrew Macumber (licensed under CCO 1.0)
Facts about Nanny-Berry
- Native to Wisconsin: Yes, throughout (Kartesz 2015)
- Native to Dane County: Yes
- Natural Habitat: Rich woods that are moist, stream banks (King 1912), swamps, roadsides (Arnold Arboretum 1919), wood edges (Mohlenbrock 1954), thickets (McCormac and Schneider 1994)
- Height: 15 ft (4.5 m) to 18 ft (5.5 m)
- Flower Color: cream to white
- Flowering Period: May to June
- USDA Hardiness Zone: 2-8
Gardening with Nanny-Berry
In your Dane County, Wisconsin butterfly garden, this viburnum requires full sun to part-shade and medium to moist well-drained soils.
5. Soft-leaf Arrow-wood (Viburnum molle), a Viburnum for Moist to Dry Well-drained high-pH Soils
Soft-leaf arrow-wood, in the wild, grows on rocky bluffs and bottomlands. It can grow to a height of 6-12 feet high and has white blossoms in the spring with blue drupes in the autumn, which are loved by birds. Suitable companion plants in the Dane County area include those mentioned above plus common ironweed (Vernonia fasciculata), smooth penstemon (Penstemon digitalis), New Jersey tea (Ceanothus americanus), gray dogwood (Cornus racemosa), Ohio spiderwort (Tradescantia ohiensis), and prairie blazingstar (Liatris pycnostachya).
Facts about Soft-leaf Arrow-wood
- Native to Wisconsin: No (Kartesz 2015)
- Native to Dane County: No
- Natural Habitat: Rocky bluff forests on calcareous substrate and bottomlands (wikipedia).
- Height: 6 ft (1.8 m) to 12 ft (3.7 m)
- Flower Color: cream to white
- Flowering Period: May to June
- USDA Hardiness Zone: 2-8
Gardening with Soft-leaf Arrow-wood
In your Dane County, Wisconsin butterfly garden, this viburnum requires full sun to part-shade and moist to dry well-drained high pH soils. However, it may be hard to find since it is rare throughout most of its range. This species is rare in the adjacent states of Illinois and Iowa.
6. Possumhaw (Viburnum nudum), a Viburnum for Medium to Wet Well-drained Soils
Possumhaw, in the wild, grows in wetland areas and reaches a height of up to 15 feet. The snowball shaped white flowers come out in May and it has a blue-black drupe in the fall that is enjoyed by birds. The leaves also have an attractive red color in the fall. Suitable companion plants in the Dane County area are different than some of the other species because of needing moist to wet soils.
Suitable companion plants include black-eyed susan (Rudbeckia hirta), New England aster (Symphyotrichum novae-angliae), little bluestem (Schizachyrium scoparium), wild bergamot (Monarda fistulosa), obedient plant (Physostegia virginiana), and cardinal flower (Lobelia cardinalis).
Because of the soils, buttonbush (Cephalanthus occidentalis), river birch (Betula nigra) and black gum (Nyssa sylvatica), can make for some taller companions in the garden.
Facts about Possumhaw
Viburnum nudum var. cassinoides in Wisconsin
- Native to Wisconsin: Yes, var. cassinoides rare in eastern counties (Kartesz 2015)
- Native to Dane County: No
- Natural Habitat: Swamps (wikipedia), seepage swamps (Belden and Derge 2003 and Sundell, et al 1999), and bogs (MacRoberts, et al 2004)
- Height: 5 ft (1.5 m) to 15 ft (4.6 m)
- Flower Color: white to cream
- Flowering Period: April to June
- USDA Hardiness Zone: 5-9
Gardening with Possumhaw
In your Dane County Wisconsin butterfly garden, this species requires full sun to partial shade and medium to wet well-drained soils. This species may be a good long-term choice, given climate change warming.
7. Highbush Cranberry (Viburnum opulus), a Viburnum for Medium to Moist Well-drained Soils
Highbush Cranberry is a small to medium sized shrub that grows in medium to moist soils. When planting this shrub, be sure you get var. americanum, which is the native variety. This variety has stalked petiolar glands, while the European variety, var. opulus, has sessile petiolar glands. Some suitable companion plants for this species are swamp milkweed (Asclepias incarnata), common milkweed (Asclepias syriaca), columbine (Aquilegia canandensis), goldenrod (Solidago spp.), and asters (Symphyotrichum spp.).
Facts about Highbush Cranberry
Viburnum opulus var. americanum: Native in Wisconsin
- Native to Wisconsin: Yes, generally throughout (var. americanum) (Kartesz 2015)
- Native to Dane County: Yes
- Natural Habitat: lowland woods (Macdonald 2003), moist woods (Bird 1961), rivershores and banks (Hosie 1938), shrub swamps (Thomson 1944), gravelly calcareous places, (Wiegand and Eames 1926), swamps and rarely dry woods (McVaugh 1958), and roadsides and field edges (Go Botany)
- Height: 8 ft (2.4 m) to 16 ft (4.9 m)
- Flower Color: yellow to white
- Flowering Period: April to June
- USDA Hardiness Zone: 2-7
Gardening with Highbush Cranberry
In your Dane County, Wisconsin butterfly garden, this viburnum requires full sun to partial shade and medium to moist well-drained soils. This species has two varieties, has two varieties, one of which, var. opulus, is exotic to North America. Variety americanum is native to North America.
8. Smooth Blackhaw (Viburnum prunifolium), a Viburnum for All Soils
Smooth blackhaw is generally found in disturbed habitats and like the small-leaf viburnum can greatly exceed the height its wild counterparts in an ideal garden setting, growing up to 30 feet. It also has white flowers and reddish-purple drupe in the fall that is loved by birds. Companion plants that provide a good color contrast include butterfly weed (Asclepias tuberosa), black-eyed susan (Rudbeckia hirta), and joe-pye weed (Eutrochium fistulosum). Since this species can handle a wide variety of soils, other companion plants are similar to the other species, althoough you may want to plant more trees or shrubs to match the height of the species.
Facts about Smooth Blackhaw
- Native to Wisconsin: Yes, rare in southeastern counties (Kartesz 2015)
- Native to Dane County: No
- Natural Habitat: Open areas, upland woods, floodplains (Gaddy 2008), disturbed habitats (Clark and Bauer 2001), thickets (Fernald 1936)
- Height: 7 ft (2.1 m) to 30 ft (9.1 m)
- Flower Color: White
- Flowering Period: May to June
- USDA Hardiness Zone: 3-9
Gardening with Smooth Blackhaw
In your Dane County, Wisconsin butterfly garden, this viburnum needs full sun to part-shade and dry to moist well-drained soils. This species can handle warmer hardiness zones than present in Dane County, making it a good long-term choice considering climate change warming.
9. Downy Arrow-wood (Viburnum rafinesquianum), a Viburnum for Dry Well-drained Soils
Downy arrow-wood is found in woodland areas in the wild and is noted for its fall foliage, which is a bronze-purple color. Growing up to 10 feet tall it has white to cream flowers and a blue-black drupe, loved by birds. Possible companion plants in the Erie County area include New York Ironweed (Vernonia noveboracensis), blazing star (Liatris spicata), swamp milkweed (Asclepias incarnata), obedient plant (Physostegia virgniana), and columbine (Aquilegia canadensis).
Facts about Downy Arrow-wood
- Native to Wisconsin: Yes, throughout (Kartesz 2015)
- Native to Dane County: Yes
- Natural Habitat: open woodlands, rocky hillside (Reaume 2009), rocky shorelines (Rousseau 1974), limestone savanna (Alvar) (Catling and Brownell 1995), dry thickets (Maycock and Eahselt (1997), and low woodlands (Fernald 1942)
- Height: 6 ft (1.8 m) to 10 ft (3 m)
- Flower Color: white to cream
- Flowering Period: May to June
- USDA Hardiness Zone: 3-8
Gardening with Downy Arrow-wood
In your Dane County, Wisconsin butterfly garden, this viburnum needs full sun to part shade and dry well-drained soils. This species is noted for its bronze-purple foliage in the fall (Koller 1981).
10. Smooth Arrow-wood (Viburnum recognitum), a Viburnum for Medium to Moist Well-drained Soils
Smooth arrow-wood can found in wetland areas and woodlands in the wild. Growing up to 15 feet tall, this species has white flowers and drupes that are loved by birds in the fall. Suitable companion plants include blazing star (Liatris spicata), butterfly weed (Asclepias tuberosa), cardinal flower (Lobelia cardinalis), and spotted Joe-Pye weed (Eutrochium maculatum).
by Bill Keim (licensed under CC BY 4.0).
Facts about Smooth Arrow-wood
- Native to Wisconsin: Yes, Adventive in scattered counties (Kartesz 2015)
- Native to Dane County: Yes, Adventive
- Natural Habitat: swamps (Dugal 1988), damp thickets (Roedner, et al 1978), thickets (Palmer 1974), secondary dunes and seasonal ponds (Lortie, et al 1991), and mesic woodland forest (Larimore, et al 2008)
- Height: 5 ft (1.5 m) to 15 ft (4.6 m)
- Flower Color: white or rarely pink (Roedner, et al 1978)
- Flowering Period: March to June
- USDA Hardiness Zone: 4-9
Gardening with Smooth Arrow-wood
In your Dane County, Pennsylvan butterfly garden, this viburnum needs full sun to part shade and moist to medium well-drained soils. This species can exist in a higher hardiness zone than is present in Dane County, making it a good long-term choice.
11. Rusty Blackhaw (Viburnum rufidulum), a Viburnum for Medium to Dry Soils
Rusty blackhaw is generally found in drier woodlands in the wild. Growing up to 20 feet tall, it has white flowers and blue-black drupes in the autumn. Companion plants that complement rusty blackhaw include butterfly weed (Asclepias tuberosa), black-eyed susan (Rudbeckia hirta), sweet Joe-Pye weed (Eutrochium purpureum), and purple coneflower (Echinacea purpurea).
Facts about Rusty Blackhaw
- Native to Wisconsin: No (Kartesz 2015)
- Native to Dane County: No
- Natural Habitat: rocky or dry woods (Steyermark 1940), limestone (Thompson, et al 2005), cedar barrens (Carr 1944), oak-hickory woodlands (Wofford, et al 1979), calcareous prairies (MacRoberts and MacRoberts 1996), and disturbed habitats (Clark and Bauer 2001)
- Height: 10 ft (3.0 m) to 20 ft (6.1 m)
- Flower Color: white to cream
- Flowering Period: April to May
- USDA Hardiness Zone: 5-9
Gardening with Rusty Blackhaw
In your Dane County, Wisconsin butterfly garden, this viburnum needs full sun to part shade and dry to medium well-drained soils. This plant can handle poor soils making it versatile for most garden situations. Rusty blackhaw is at the bottom limit of its cold hardiness in Dane County, so it may need to be protected during cold snaps.
When selecting your Dane County, WI viburnum, be sure to make sure that it grows in your zone and habitat.
Books where you can find out more about Butterfly Gardening in Dane County, WI
- Diekelmann, John. 2002. Natural Landscaping: Designed with Native Plant Communities. University of Wisconsin Press. 320 pp.
- Kavanagh, James. 2020. Wisconsin Butterflies & Pollinators: A Folding Pocket Guide to Familiar Species. Waterford Press. 12 pp.
- Krieg, Jean. 2018. My First Book of Common Wisconsin Butterflies. Createspace Independent Publishing Platform. 40 pp.
- Nowak, Mariette. 2012. Birdscaping in the Midwest: A Guide to Gardening with Native Plants to Attract Birds. University of Wisconsin Press. 352 pp.
- Smith, J. Robert and Beatrice S. Smith. 1980. The Prairie Garden: Seventy Native Plants You Can Grow in Town or Country. University of Wisconsin Press. 232 pp.
- Steiner, Lynn M. 2007. Landscaping with Native Plants of Wisconsin. Voyageur Press. 192 pp.
- Weber, Larry. 2006. Butterflies of the North Woods: Minnesota, Wisconsin & Michigan. Kollath-Stenaas Publishing. 288 pp.
Affiliate Disclosure: When you click on links to various merchants on this site and make a purchase, this site can earn a commission at no extra cost to you. Affiliate programs include, but are not limited to, the eBay Partner Network, Thriftbooks, and Blackwell’s Books.
References for Dane County, WI Viburnums
- Arnold Arboretum. 1919. Viburnum lentago. Bulletin of Popular Information. 5 (7): 28.
- Belden, Allen and Katherine L. Derge. 2003. The flora and fauna of Virginia Army National Guard OMS No. 1 and No. 2 near Sandston, Henrico County, Virginia. Banisteria 22: 22-42.
- Bird, Ralph Durham. 1961. Ecology of the aspen parkland of western Canada in relation to land use. (Ottawa: Canada Department of Agriculture).
- Bouchard, Andre’, Denis Barabe’, Madeliene Dumais, and Stuart Hay. 1983. The Rare Vascular Plants of Quebec. (Ottawa, ON: National Museum of Natural Sciences).
- Catling, Paul M. and Vivian R. Brownell. 1995. A review of the Great Lakes Region: Distribution, floristic comparison, biogeography, and protection. The Canadian Field-Naturalist 109 (2): 143-171.
- Carr, Lloyd G. 1944. A New Species of Houstonia from the Cedar Barrens of Lee County, Virginia. Rhodora 46: 306-310.
- Clark, Ross C. and Ryan M. Bauer. 2001. Woody Plants of Six Northern Kentucky Counties. Journal of the Kentucky Academy of Science 62(1): 39-51.
- Dugal, Albert W. 1988. Southern Arrow-wood, Viburnum recognitum, A Rare Ontario Species in the Ottawa District. Trail & Landscape 22 (4): 151-155.
- Fernald, Merritt Lyndon. 1942. The Seventh Century of additions to the flora of Virginia. Rhodora 44: 457-479.
- Fernald, Merritt Lyndon. 1936. Plants from the Outer Coastal Plain of Virginia (continued). Rhodora 38: 414-452.
- Gaddy, L.L. 2008. A New Sessile-Flowered Trillium (Liliaceae: Subgenus Phyllantherum) from South Carolina. Phytologia 90 (3): 382-390.
- Gillet, John M. 1954. A plant collection from the Mealy Mountains, Labrador, Canada. The Canadian Field-Naturalist 68 (3): 118-122.
- Hosie, R.C. 1938. Botanical Investigations in Batchawana Bay Region, Lake Superior. National Museum of Canada: Bulletin 88.
- Kartesz, J.T. The Biota of North America Program (BONAP). 2015. Taxonomic Data Center (BONAP). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].
- King, Wilbur. 1912. The Flora of Northampton County, Pennsylvania. Torreya 12: 208-215.
- Koller, Gary. 1981. Shrubs for Hillsides and Embankments. Arnoldia 41: 193.
- Larrimore, Richard L., Loy R. Phillippe, and John E. Ebinger. 2008. Vascular Flora of Middle Fork Woods Nature Preserve, Vermillion County, Illinois. Illinois Natural History Survey Bulletin 38, article 4.
- Lortie, J.P., Bruce A. Sorrie, D.W. Holt. 1991. Flora of the Montgomery Islands Chatham, Massachusetts. Rhodora 93: 361-389.
- Macdonald, Ian D. 2003. A rare plant survey of the Wainwright Dunes Ecological Reserve. (Edmonton, Alberta: Alberta Sustainable Resource Development).
- MacRoberts, Michael H., Barbara R. MacRoberts, and Lynn Stacey Johnson. 2004. Observations of Parnassia grandifolia DC. (Saxifragaceae) in the West Gulf Coast Plain. Phytologia 86: 98-103.
- MacRoberts, Barbara R. and Michael H. MacRoberts. 1996. The floristics of calcareous prairies on the Kisatchie National Forest, Louisiana. Phytologia 81: 35-43.
- Maycock, Paul F. and Dianne Eahselt. 1997. An inventory of ecologically significant natural vegetation in the province of Ontario: 1. Essex County. The Canadian Field-Naturalist 101: 474-486.
- McCormac, J.S. and G.J. Schneider. 1994. Floristic Diversity of a Disturbed Western Ohio Fen. Rhodora 96: 327-353.
- McVaugh, Rogers. 1958. Flora of the Columbia County area, New York. (Albany, NY: University of the State of New York).
- Mohlenbrock, R.H. 1954. Some notes on the flora of Southern Illinois. Rhodora 56: 227-228.
- Palmer, Ernest J. 1947. Second supplement to the spontaneous Flora of the Arnold Arboretum. Journal of the Arnold Arboretum 28: 410-418.
- Raup, Hugh M. 1947. Botany of Southwestern MacKenzie. Sargentia 6: 1-275.
- Raup, Hugh M. 1946. Phytogeographic Studies in the Athabaska-Great Slave Lake Region, II. Journal of the Arnold Arboretum 1: 1-85.
- Reaume, Tom. 2009. Biology of the Downy Arrow-wood (Viburnum rafinesquianum). Blue Jay 67 (2): 89-96.
- Roedner, Beverly J., David A. Hamilton, Keith E. Evans. 1978. Rare Plants of the Ozark Plateau: a field identification guide. USDA: North Central Forest Expriment Station.
- Rousseau, C. 1974. Ge’ographie floristique de Que’bec/Labrador. Distritbution des principales especes vascularies. Les Presses de of I’Unversitie Laval. Quebec 799 pp. in (Bouchard, et al 1983).
- Steyermark, Julian. 1940. Studies of the vegetation of Missouri – I. Natural Plant Associations and Succession in the Ozarks of Missouri. Botanical Series Field Museum of Natural History 9(5): Publication 485.
- Sundell, Eric, Thomas R. Dale, Carl Amason, Robert L. Stuckey, and John Logan. 1999. Noteworthy Vascular Plants from Arkansas. Sida 18: 877-887.
- Thieret, John W. 1964. Botanical Survey Along the Yellowknife Highway, Northwest Territories, Canada: II. Vegetation. Sida 1: 187-239.
- Thompson, Ralph L., J. Richard Abbott, Andrew E. Shupe. 2005. Vascular Flora from Five Plant Habitats of an Abandoned Limestone Quarry in Clark County, Kentucky. Journal of the Kentucky Academy of Science 66 (1): 24-34.
- Thomson, John W. 1944. A Survey of the Larger Aquatic Plants and Bank Flora of the Brule River. Transactions of the Wisconsin Academy of Science, Arts, and Letters. 36: 57-76.
- Wiegand, K.M. and Arthur J. Eames. 1926. The flora of Cayuga Lake Basin, New York Vascular Plants. (Ithaca, NY: The University Memoir 92).
- Wofford, Eugene B., Thomas S. Patrick, Loy R. Phillippe, David H. Webb. 1979. The Vascular Flora of Savage Gulf, Tennessee. Sida 8: 135-151.
