T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Hydrocotyle Information

Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
(Unranked): Asterids
Order: Apiales
Family: Araliaceae
Subfamily: Hydrocotyloideae
Genus: Hydrocotyle
Species: There are ten species listed for this genus in the "Flora of New Zealand Vol 4".
Common names: Waxweed, Hydrocotyle, water pennywort, Marsh penny,

Hydrocotyle is a troublesome weed in turf because it tolerates many of the herbicides used selectively in grass turf. It is typically found in damp, shady environments. All of the hydrocotyle species are perennials with a stolon system (i. e. creeping, rooting stems). Hydrocotyle can also sometimes cause problems in overgrazed pastures in damp parts of the country, creating low-growing dense mats that exclude most other vegetation.

The leaves of the hydrocotyle species are typically about 1 cm in diameter, but can get much smaller than this in very tightly mown bowling greens or golf greens, and can also get considerably larger than this if the plants are left unmown or ungrazed for several weeks or months.

Hydrocotyle is the common name given for most species from the Hydrocotyle genus. There are ten species listed for this genus in the "Flora of New Zealand Vol 4".

Few people can actually differentiate between all 10 of them, there are three native to New Zealand common ones found in turf. To tell the above mentioned hydrocotyle species apart, it's probably best to look at the side-by-side leaf photos.

1 There is a hairy one called Hydrocotyle moschata.
2 The one with very shiny leaves is called Hydrocotyle heteromeria (waxweed).
3 The other common one appears to be Hydrocotyle novae-zeelandiae, which is quite a variable species.
4 The fourth species (not native) growing in NZ is Hydrocotyle tripartite (Australian hydrocotyle). Its leaf breaks up into three separate leaflets like a buttercup.

Thanks to  Dr Kerry Harrington, Senior Lecturer Institute of Natural Resources Massey University for the above information.