Typha latifolia
(broadleaf cattail)

T. latifolia is a cosmopolitan plant, occurring in wetlands through most temperature zones in North America, Europe and Asia, and many subtropical areas. It has also begun to invade the few regions where it is not native, e.g., Oceania, South-East Asia and the Hawaiian islands. It forms dense populations under suitable conditions, often as monocultures excluding other species of vegetation. Holm et al. (1997) designated it as one of the “World’s Worst Weeds”. T. latifolia can reduce rice production, impact wildlife populations and can alter nutrient cycles negatively. In New Zealand it is classed as an “unwanted organism” as part of the National Plant Pest Accord (Champion et al., 2007). Potential for rapid clonal growth and long persistence of T. latifolia in areas where it is native presents a warning against establishment of this species in areas where it is not native and would impact native biodiversity.

T. latifolia is a cosmopolitan species, with its native range encompassing large regions on all continents, except Antarctica, Africa and Oceania. T. latifolia is known to occur in at least seven African countries (USDA-ARS, 2010). It is recorded as having been established as a non-native species in six countries (Australia, Indonesia, Malaysia, New Zealand, Papua New Guinea, the Philippines) and the USA state of Hawaii (Global Invasive Species Database, 2006). In New Zealand, it is not presently established but it has been found within the nursery/aquarium trade (Champion et al., 2007). T. latifolia is currently recorded as naturalized in low-lying wet areas on three of the Hawaiian islands: Kauai, Hawaii (the big island), Maui and Oahu (Wagner et al., 1999; HISP, 2008; PIER, 2009). Given the ability of T. latifolia to thrive in a broad array of temperature or semi-tropical habitats from the Arctic circle to 30°S latitude (Sculthorpe, 1967), T. latifolia may also be established on other oceanic islands with suitable wetland habitats (but not recorded). It is also increasingly seen as taking on invasive characteristics in some countries where it is native (Shih and Finkelstein, 2008; Olson et al., 2009). Furthermore, the hybrid product of T. latifolia and T. angustifolia, T. x glauca tends to be more invasive than T. latifolia (Olson et al., 2009).

A risk assessment was carried out for T. latifolia according to the Australian/New Zealand Weed Risk Assessment adapted for Hawaii (PIER, 2008). This identified T. latifolia having a high risk of invasion for the Pacific Islands, based on information from throughout the world on invasive features of T. latifolia such as high levels of seed production, persistence of seeds and rhizomes, and ability to form monocultures in wetland areas. There are few temperate or subtropical regions in the world where T. latifolia is not found, and therefore it would appear that this highly adaptable species is a threat to invade areas where it does not exist, especially if transported anthropogenically, either intentionally or accidentally.

T. latifolia grows in a wide variety of wetland habitats. Niches include marshes, wet meadows, lakeshores, roadside ditches, seacoast estuaries, pond margins, bogs or fens as well as rice paddies (Grace and Harrison, 1986). Salt tolerance is limited, but it does grow in marine wetlands with moderate salinity, and likewise can tolerate acidity (Hotchkiss and Dozier, 1949; Smith, 1967a,b; Hootsmans and Weigman, 1998). Communities occupied by T. latifolia range from early to late successional stages. Although it is a dominant species in many wetlands forming high densities, in other wetlands it occurs as scattered individuals or clumps. It also may occupy somewhat drier sites, such as along the edge of marshy woodlands or among woody shrubs (Grace and Wetzel, 1981a). It tends to prefer shallower water zones than T. angustifolia (Grace and Wetzel, 1981b). The only type of agricultural habitat where T. latifolia regularly occurs is in rice paddies (Mitich, 2001).

Flooding and water depth are key determinants of the establishment and persistence of T. latifolia populations. Tolerance of fluctuating water levels depends on a variety of factors, including the maturity of plants, rhizome production, associated vegetation and other disturbances (Grace, 1989; Gucker, 2008). As an emergent plant, optimal water levels tend to be high enough to keep lower parts of the plants submerged, but low enough to prevent interference with photosynthesis and respiration. Controlled experiments showed decreased rhizome production at water levels above 30 cm (Weller, 1975). T. latifolia died in water depths over 95 cm and density was greatest at 22 cm depths in experimental ponds in Arkansas (Grace, 1989). Oxygen is transported from aerial portions to rhizomes to allow survival and growth so long as enough of the plant is above water (Sale and Wetzel, 1983). T. latifolia has been found to tolerate drying of wetlands over several months (Fickbohm and Zhu, 2006), but perish if water was drained for a period of 2 years (Nelson and Dietz, 1966).

Various ungulates have been found to graze on T. latifolia including livestock (e.g. cattle) as well as wild ungulates, e.g. deer, elk or moose (Boggs et al., 1990; USDA-ARS, 2010).

Animal feed, fodder, forage

• Forage

Environmental

• Amenity
• Landscape improvement
• Revegetation
• Wildlife habitat

Fuels

• Biofuels

General

• Botanical garden/zoo
• Pet/aquarium trade
• Research model
• Sociocultural value

Human food and beverage

• Flour/starch
• Vegetable

Materials

• Alcohol
• Chemicals
• Essential oils
• Mulches
• Poisonous to mammals

Medicinal, pharmaceutical

• Traditional/folklore

Ornamental

• Propagation material

A survey was conducted among people in the aquatic plant trade in New Zealand (Champion and Clayton, 2001), and in the process provided information on identification so that T. latifolia could be distinguished from the native Typha species, T. orientalis (Champion et al., 2007). In particular,characteristics used to distinguish T. latifolia were: leaf sheaths tapering to lamina, female flower lacking scales, female spike dark brown, male and female spikes of similar lengths, and the grouping of pollen grains in tetrads. The identification utilized literature resources such as Fassett and Calhoun (1952), Aston (1973), Tutin et al. (1980), and Smith (1967a,b). The two species as well as T. laxmannii, another potential invader of New Zealand, are illustrated in Champion et al. (2007).

By comparison to T. orientalis (raupo) (native to New Zealand and Australia), the leaves of T. latifolia are broader, flatter and paler, and the flower spark is black-brown in colour compared with the chestnut brown of T. orientalis (Champion et al., 2007).

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

T. latifolia has frequently been planted and/or managed to provide ecosystem services in wetlands to promote wildlife habitat, stabilize shorelines or reduce contaminants or even salinity (Marsh, 1962; Gopal and Sharma, 1980; Bonham, 1983).

There is a need for further research on management, particularly in areas where it is not-native. Almost no work has been done to examine the potential for biological control. There is also a great need for more work to look at specific impacts T. latifolia has on biodiversity on all levels.

23/04/10 Original text by:

David Clements, Biology and Environmental Studies, Trinity Western University, 7600 Glover Road, Langley, British Columbia, V2Y 1Y1, Canada