Last updated: November 30, 2023
Article
Six Invasive Viburnums in the Greater Washington Area
Adapted from a Weed Alert by Yvonne Ng, Community Volunteer Ambassador for the National Capital Region Invasive Plant Management Team
There are a plenty of invasive viburnums to lookout for, but six merit special attention because they’re commonly found in the DC, Maryland, and Virginia region:
- Linden arrowwood (V. dilatatum)
- Doublefile viburnum (V. plicatum f. plicatum)
- Snowball viburnum (V. plicatum f. tomentosa)
- Siebold viburnum (V. sieboldii)
- Tea viburnum (V. setigerum)
- Lantanaphyllum viburnum (V. x rhytidophylloides)
These viburnums are all native to East Asia, primarily China and Japan, brought in for ornamental use and are still sold commercially. They outcompete native flora, including our own native viburnums, due to dense growth and vigorous fruit production.
Common Traits
Viburnums range from woody shrubs to small trees. They’re deciduous and lose their leaves each fall. All five focal species have opposite leaves (that mirroring each other on each branch). Viburnums flower April through August and fruits will start to appear between late August through September. Their flowerheads are flat-topped with clusters of creamy, white, star-shaped florets with 5 long stamens that later form clusters of droopy fruits. Of course, there will be some exceptions to these characteristics. Viburnums fruit in fall and that’s a great time of to identify them. Follow the descriptions below to ID a viburnum. You can also check out Cornell University’s Guide to Identifying Viburnums and their express key, but note that there will be some variation when using an identification key.
Flowers, Emilio Concari (CC BY-NC 4.0); entire plant, msperr (CC BY-NC 4.0); fruit, Gary Smith (CC0 1.0); fruits in frost, Matt Schultz (CC0 1.0); bark, Katja Schulz (CC BY 2.0); bud, Emily Summerbell (CC BY 4.0); leaves, Tom Pollard (CC BY 4.0)
Linden arrowwood Viburnum (V. dilatatum)
Linden arrowwood (Viburnum dilatatum) can grow up to 8-13 feet tall. They have a habit of forming dense thickets and suckers that take extra nutrients from the parent tree. Of all the viburnums, the leaves on V. dilatatum are mostly egg-shaped and are soft to the touch from hairs on both sides of the leaf. The leaves have a silverish underside and trap dust, which can make them appear dirty. It is worth mentioning that V. dilatatum has the most variation in leaf shapes, even along the same stem. When identifying V. dilatatum, check the back of the leaf and see if there are two to four little indentations or glands at the base of the leaf. Young stems are fuzzy with small orange lenticels that will mature to smooth gray-brown stems with prominent orange lenticels.
The flowerheads on V. dilatatum are flat topped and may have an unpleasant smell. When looking at the tubular, star-shaped flowers, the petals are rounded. In autumn, the leaves will turn dull red before falling and yellow 5-8 mm fruits start to appear. Soon, they will mature to a red color and persist through winter. The fruits of this species are often oblong and may be shaped like the flame of a candle. Most other viburnum species have round fruit.
entire plant, Patty Haynes (CC BY-NC 4.0); snowball flowers, Charlie H (CC BY-NC 4.0); snowball flowers, Henggang Cui (CC0 1.0); bark, Andrew Block (CC BY-NC 4.0), iNaturalist; and fruits, Lynn Harper (CC0 1.0).
Japanese Snowball Viburnum (V. plicatum f. plicatum)
Japanese snowball (Viburnum plicatum f. plicatum) is a cultivar of the naturally occurring non-native doublefile viburnum (Viburnum plicatum f. tomentosa). The two are often grouped together when talking about Viburnum plicatum. I present them separately here since they have some different characteristics. Japanese snowball can be considered a small tree as it can group up to 15 feet tall. As the common name suggests, the flowers are bright white and round. You’ll see these snowball flowers in opposite arrangement growing from the nodes. Japanese snowball is sterile and cannot cross-pollinate or produce fruit; they don’t have any fragrance to them as well.
Leaves are dark green with a pleated surface, hairy underside, ovate shape, and can turn burgundy to purple in autumn. The bark of the trunk is dark gray-brown, hairless, and can have a smooth or ridged texture.
Doublefile Viburnum (V. plicatum f. tomentosa)
Doublefile viburnum (Viburnum plicatum f. tomentosum) is the fertile version of Japanese snowball. Like many older-younger sibling dynamic, this older sibling can reach only up to 10 feet. As far as I could find, they share the same leaf characteristics, with the ovate shape, dark green color, pleated surface, hairy underside, and autumn colors. In both varieties, the leaves will have many pairs of veins, typically no less than 11 pairs and often up to 16 on each leaf.
The bark for doublefile is also gray-brown with orange spots throughout the trunk. While the trunk is smooth and hairless, the younger stems are densely hairy. The flowers are not as showy as snowball viburnums, but are sweet-smelling. These flowers are a creamy yellow compared to the typically creamy white color of the rest of the viburnums listed here, and are surrounded by bright white bracts (sterile flowers) that each have 4 to 5 petals. The fruits on both forms of this species first appear red and mature to black.
flowers, Edward J. Norton (CC BY-NC 4.0); entire plant, Chris Grove (CC BY-NC 4.0); fruits, Mattthew R. Halley (CC BY-NC 4.0); bark, tkr421 (CC BY 4.0); and leaves, Yann Kemper (CC0 1.0), iNaturalist.
Siebold Viburnum (V. sieboldii)
Siebold viburnum (Viburnum sieboldii) is the tallest amongst its brethren, a 15-20 foot tall giant. The leaves on Siebold are lanceolate to oblong shape, dark green with a pale underside, and have no hairs on either side. When crushed, they smell like burnt rubber.
Siebold flowers are similar to Viburnum dilatatum but less rounded at the top of the petal. In August to September, red fruits occur on red stems. When ripe, the fruit will turn black.
fruits, Bill Fuchs (CC BY-NC 4.0); entire plant; Josh Rudder (CC BY-NC 4.0); underside leaf veins, Jim Keesling (CC BY-NC 4.0); bark, Steve Markle (CC BY-NC 4.0); leaves changing color, Jim Keesling (CC BY-NC 4.0), flowers, annamauramc (CC BY-NC 4.0)
Tea Viburnum (V. setigerum)
Tea viburnum (Viburnum setigerum) grows between 8-12 feet tall and forms a vase shape. The leaves are lanceolate to oblong, green-blue-silver to dark green in color, have hairs along the back side of the veins, and slight teeth along the leaf margins. During mid-summer, the foliage becomes a unique muted red in between the veins. The flower is most similar to Viburnum dilatatum with similarly shaped petals though with a pleasant smell instead. The flower head appears in much smaller clusters: 1 to 2 inches in diameter compared to the other viburnum inflorescences here being 2 to 6 inches in diameter. In September, the fruit will emerge as yellow-orange and mature to red.
leaves, Susan Strine (CC BY 2.0), North Carolina State University Extension; plant, derwinmcg (CC BY-NC 4.0); fruits, Jared Del Russo (CC BY-NC 4.0), iNaturalist; bark, Kathleen Moore (CC BY 2.0); flowers, Susan Strine (CC BY 2.0); NCU Extension
Lantanaphyllum viburnum (V. x rhytidophylloides)
Viburnum x rhytidophylloides is probably the most unique of the viburnums described here. It is a hybrid between Viburnum lantana (wayfaring-tree) and Viburnum rhytidophyllum (leatherleaf viburnum), both of which are non-native to the US.
Viburnum x rhytidphylloides is a semi-evergreen shrub, meaning that some leaves can be entirely evergreen or just partially fallen if the winter is mild enough. As the plant matures, it begins to mound and grow suckers at the base of the trunk. The foliage is dark green on the front and pale on the underside with entire or sparsely toothed margins. The leaves can be lanceolate to oblong with a crinkled appearance and become wind-burned, especially in the winter. They also have hairy stems that emerge as a fuzzy green-white and become brown-orange as they mature. The inflorescence is more rounded at the top and is clustered tightly together with an unpleasant smell.
This hybrid is able to clone and produce red to black fruit, but its best fruit production takes place when one or both parents are present. While V. x rhytidophylloides is not common in the wild within the region, iNaturalist observations of one of the parents, V. rhytidophyllum, have increased over the past 3 years. This could present an issue in the future.
Tips for making a good observation record of species
Take photographs that show:
- the landscape around the plant—this shows the context and offers a clue to the scale of the infestation
- if they are flowering, get a close-up photo of the flowers
- if they aren’t flowering yet, photograph a whole plant since some of these have different growing habits, as well as the leaves and stems
Add comments that:
- are explicit about the issue of intentional plant vs weed vs escaped
- give a rough estimate of the number of patches and the area covered
- any other comments you think might be helpful
More on Invasive Plant Management
The National Capital Region’s Invasive Plant Management Team (NCR IPMT) supports 12 parks across four states and the District of Columbia, providing expertise and assistance to restore native ecosystems through management of invasive vegetation.
NCR IPMT partners with the National Capital Partnership for Regional Invasive Species Management (NatCap PRISM) in and surrounding areas outside of the 12 national parks supported by IPMT. NatCap PRISM provides citizen science engagement, outreach and forums, and volunteer opportunities to help combat species designated as early detection and rapid response species, before they can become invasive across greater DC Metropolitan area. Members of the NatCap PRISM work together to protect biodiversity by minimizing the adverse impacts of invasive species on ecosystems throughout the NCR.