Asian jumpseed – Persicaria filiformis | May 14, 2022 | Maryland Invasive Species Council
Contacts: Judy Fulton, EcoPlant Consulting, judy@ecoplantconsulting.com | Sara Tangren, National Capital PRISM
Asian jumpseed cultivars are often sold or traded as plants native to Maryland. Plant enthusiasts frequently mistake this foreign interloper for a native due to a history of taxonomic confusion in the genus generally, but with our native Virginia knotweed specifically. It also doesn’t help that the two species look a lot alike. As a result, gardeners who think they are buying a native and being ecologically responsible can actually be spreading a highly invasive plant. To make matters worse, gardeners often share this prolific grower with their friends. Asian jumpseed has only recently started to escape into natural areas; so, now is the time to practice “early detection and rapid response” (EDRR). Because May is the month when both the native and non-native species are starting to leaf-out fully, the Maryland Invasive Species Council has selected Asian jumpseed as the May Invader of the Month.
Asian jumpseed (Persicaria filiformis) was once incorrectly considered a variety of Virginia knotweed (Persicaria virginiana) and named Persicaria virginiana var. filiformis or Polygonum virginianum var. filiforme. It is a perennial forb that grows up to 2½’ tall earlier in the summer before flowering. Alternate, simple leaves include a sharply pointed, dark maroon to pink or dark green chevron—an upside-down V. The chevron usually persists but can start fading towards fall. Besides the “V”, plants can have leaves that are either plain green or variegated. When the leaves include whitish-cream coloring, they are offspring of the popular ‘Painter’s Palette’, but more often this cultivar’s descendants have the non-variegated form. Plants with green leaves may also be offspring of the non-variegated ‘Lance Corporal’ or ‘Batwings’. From mid-summer through early fall, very small, crimson to pink flowers bloom, spaced along thin, arching terminal spikes that extend up to a foot above the foliage. Seeds are contained in small, hooked fruits. A single plant can drop many seeds to the ground nearby, or they can “jump” 10’ from the stalk when touched. The hooked fruits can also hitchhike to more distant locations on animal fur or get carried still farther away by water to invade fresh territory.
Virginia knotweed or jumpseed (Persicaria virginiana a.k.a. Polygonum virginianum or Tovara virginiana) is similar to Asian jumpseed in growth habit, height, and seed dispersal mechanisms. However, the native’s chevron has less distinct edges than the well-defined V of Asian jumpseed. Besides, this dark mark appears only on the younger leaves of Virginia knotweed, and then soon fades away as they mature. The chevron is especially noticeable on the first foliage of the year, but also shows in a lighter version on new growth throughout the summer. As the days of spring give way to summer, a subtle difference in leaf shape becomes apparent: leaves of Virginia jumpseed appear narrower with a more rounded base and elongate tip. Leaves of Asian jumpseed have a more wedge-shaped base and appear broadest closer to the tip. You can see the seasonal progression in the shapes and chevrons from the spring leaves below to the mature leaves above. Virginia jumpseed almost always has greenish-white flowers compared to the Asian’s reddish-pink flowers.
Asian jumpseed, also called Japanese jumpseed, originally came from East Asia (i.e., China, India, Japan, Korea, Myanmar, the Philippines, Vietnam, and the Kuril Islands). Like its native cousin, the foreigner prefers to grow in part shade in very moist to medium-dry soil. You can find the invader massing in forested uplands and floodplains. In the DC-Baltimore Metro area, invasive populations are spreading in Baltimore County, Maryland, and Arlington County, Virginia (Simmons et al. 2020). The invasive is increasingly escaping throughout the mid-Atlantic region, out to Ohio and up to Massachusetts, as well as other locations in the U.S. and Canada (iNaturalist, Weakley’s 2022 Flora).
Wherever this vigorous invasive finds itself, it forms large, dense monocultures that shade out native plants. Because Persicaria species are rarely eaten by wildlife, the invasive easily outcompetes natives more palatable to deer and other herbivores. Due to Persicaria species’ tendency to hybridize, it is also possible that Asian jumpseed could be interbreeding with Virginia knotweed and so altering the native’s genetics. In natural areas, you might find tons of non-variegated plants mixed with a few variegated invasives and even a handful of the Virginia jumpseed.
To keep Asian jumpseed from becoming widely established, resist the temptation to plant it. Instead, the deer-resistant Virginia jumpseed can serve as an attractive, wild addition to your landscaping. If you already have the invasive in your garden, pull or dig up every one of the plants, preferably before they go to seed. And try to convince your friends likewise. You will not be able to keep Asian jumpseed from escaping from your yard because animals will carry it to other locations. In natural areas, practice Early Detection and Rapid Response by learning how to recognize the invasive, reporting it via EDDMapS, and removing the interlopers you find. Although individual specimens are relatively easy to remove, roots and all, it is amazing how quickly the plants become unmanageable. The infestations that form in just a few years might require too much time and effort to control by hand. For these, a systemic herbicide might be the only option.
References:
A.S Weakley and the Southeastern Flora Team. Ed. April 24, 2022. Flora of the Southeastern United States. Produced by M.T. Lee from FloraManager database system. University of North Carolina at Chapel Hill Herbarium, North Carolina Botanical Garden, University of North Carolina at Chapel Hill. ncbg.unc.edu/research/unc-herbarium/flora-request.
iNaturalist. iNaturalist, LLC. Accessed on 5/14/2022. inaturalist.org.
R H. Simmons, W.C. Taylor, M.E. Farrah, J.S. Graham, and J.P. Fulton. 2020. Noteworthy Collections: Maryland and Virginia. Castanea 85(2): 277–284. https://bioone.org/journals/castanea/volume-85/issue-2/0008-7475.85.2.279/Noteworthy-Collections-Maryland-and-Virginia/10.2179/0008-7475.85.2.279.short.
Early Detection and Distribution Mapping System (EDDMapS). University of Georgia, Center for Invasive Species and Ecosystem Health. eddmaps.org.