What does it look like?
Spartina is an estuarine grass that grows in clumps up 1.5 metres tall. S. alterniflora is the most common spartina species in Northland, and is the more robust of the two, with shoots up to 30mm in diameter. Spartina anglica is smaller, with shoots up to 8mm in diameter. S. townsendii is a rare hybrid plant, rarely found north of the Kaipara Harbour.
Spartina grows in soft sediment at wave-protected sites on the edges of estuaries and harbours. It grows in the inter-tidal zone, often with mangroves.
Why is it a problem?
Spartina is an aggressive and persistent invader of inter-tidal mudflats. It can take over inter-tidal areas, leading to a loss of habitat for shorebirds, recreational fisheries and seafood. The dense growth of spartina traps sediment, which can eventually raise the ground level to a point where the area is no longer inter-tidal. Extensive infestations can cause surface flooding on adjacent land.
Spartina alterniflora is not known to set seed in New Zealand and Spartina anglica produces only small amounts. Both species reproduce vegetatively, from spreading rhizomes (roots).