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Technical Note #24 from Watershed Protection Techniques. 1(2): 83 Broad-Leaf Arrowhead: A Workhorse of the Wetland

he broad-leaf arrowhead (Sagittaria 3. Heavy metal uptake. In surveys in South Caro- latifolia) is a native North American lina and Michigan, broad-leaf arrowhead was Twetland plant found in southern Canada found to have the highest leaf dry weight con- and much of the United States. Many practitio- centrations of several metals. ners have found it especially useful for wetland 4. Ease of plant propagation. Wetland plant enhancement, restoration, and cre- vendors can supply achnenes, tubers, and ation projects because of several container-grown plants. Tubers are desirable characteristics. However, generally preferred because they Marburger (1993) points out there is require less site preparation. Plants still much to be learned about its are more costly, but survive a ecology and physiology before rou- wider range of initial conditions. tinely investing in large scale planting and management schemes. 5. Resistance to disease and dam- age. There are few reports of The plant is identified by its ro- population reductions due to settes of arrowhead-shaped leaves. Flow- pathogens, insect pests, and animal ers are white with three petals and arranged feeding. In some limited situation it may be in whorls around a long stalk. Its most dis- necessary to enclose areas with protective tinctive feature is the starchy tuber produced fencing to keep out muskrats and waterfowl. from the rhizomes. This phenomenon gives rise to its common name of duck potato. This In spite of many apparent field successes, “potato” portion of the plant is consumed Marburger points out there exists only a by muskrats, porcupines, geese, and other limited database on the installation and animals. Native Americans and European management of the broad-leaf arrow- settlers also used the tuber as a food Adapted from Fassett, 1960 head, especially for large-scale source. applications. Before incorporating the arrowhead in a wetland design the practitioner While its days as human food have long since past, needs to work with plant vendor to identify the other beneficial characteristics of broad-leaf arrowhead following: have propelled it into the field of wetland restoration. Special characteristics include the following. • If the environmental factors at the site are more favorable for germinating/growing achenes, tu- 1. Adaptation to a wide range of conditions. The bers, or seedlings plant persists under stabilized water levels of less than 50 cm and few drawdowns and survives in • If environmental factors are right for sustaining pHs from 5.9 to 8.8. It has been found in highly a mature population of arrowheads calcareous water and in a variety of soil types • If pathogens, animal herbivory, and/or other including sandy loams and silty clays. While it can plant species are likely to impact the plant withstand turbid conditions, it does not tolerate severe sediment deposition. References —JS Boyd, C.E. 1970. "Chemical Analyses of Some Vascu- 2. Nutrient uptake. Arrowhead rapidly takes up lar Aquatic Plants." Archiven für Hydrobiologie phosphorus from the sediments and retains it in its 67:78-85. tissue. In one South Carolina study it had the highest leaf tissue composition of phosphorus of Fassett, N.C. 1960. A Manual of Aquatic Plants. The 17 wetland plants analyzed (Boyd, 1970). For this U. of Wisconsin Press, 405 pp. reason arrowhead is often selected for use in Marburger, J.E., 1993. "Biology and Management of municipal and domestic wastewater treatment sys- Sagittaria latifolia Willd. (Broad-leaf Arrow- tems, constructed wetlands, and for stormwater head) for Wetland Restoration and Creation." runoff treatment. Restoration Ecology 1(4) 248-257.

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