Hydrocotyle (Hydrocotyle spp)

Hydrocotyle is also known as Pennywort, Dollar Weed and Kurnells Curse. It is a perennial, is a problem in lawns and turf, and it is often present in sandy soils on coastal areas. It has this name because of the shape of its leaves. These resemble a dollar, or a lily pad being 25-50mm in diameter.

Dollar Weed is a prostrate, aggressive ground-creeping plant. If you do not control this it tends to form a dense mat of growth which outcompete exsting vegetation. The leaves of all species are close to circular in shape, and up to about 10mm in diameter.

When you lower the height of cut by mowing on golf and bowling greens, the leaves tend to be smaller. In unmown areas are be larger, being up to up to 20mm in diameter.

Hydrocotyl has lots of horizontal creeping stems, and it roots at each node. When you crush it, it gives off a strong odour.

 After you finish reading this, you will be able to:

• Identify Hydrocotyle.
• Know the habitat of Hydrocotyle.
• Know the best cultural and chemical options to control Pennywort.

For more information, please check out our weed ID chart. Hydrocotyle is a good indicator weed of wet soils.

Hydrocotyle Identification.

Pennywort is has a large taproot and many smaller taproots. These develop at each node in contact with the ground.

Category: broadleaf (Dicot).

Flower: The flower is yellow or white and present all year, but mainly from October to February.

Height: Pennywort is prostrate.

Leaf Length:

Leaf Width: The blade is circular to elliptical, 1.2 to 12 cm in diameter

Reproduction: It spreads by seeds, rhizomes, and tubers.

Comments: The margin of Dollar Weed is roughly crenated. The leaf has a dull green colour, and divides into distinct segments.

Dollar Weed is often confused with Kidney Weed. A good way to tell them apart is to look at the leaf stem placement. The stem of Kidney Weed is in the centre of the leaf, while Dichondra’s stem is at the edge.

Habitat: It favours moist soil conditions. Dollar Weed thrives in weak, thin turf in wet soil.

Although cultural or mechanical means of removal are generally unsuccessful, if you want to go down this path the following may help.

The key to cultural managment is to not to over water and fix any drainage issues. Low areas that don’t drain very well are ideal for Dollar Weed so if you have low spots deal with them. If you see it in your lawn, it’s likley you are over watering or its thriving in areas of poor drainage. University of Florida research has demonstrated a reduction in Dollar Weed just by reducing irrigation frequency.

So if you cut back on irrigation and mow at the right height for your turf grass it goes a major way towards the control of this weed.

Removing this weed mechanically does not work well, and usually in most cases the weak leaf stem is snapped off leaving the underground stem in the ground.

On a sandy well drained bowling green or golf green over watering is normally the problem.

In bowling greens the growth of Hydrocotyle is most aggressive in damp patches, so removal of even very slight hollows and not overwatering discourages Hydrocotyle.

In lawns the same is also true. Shade also comes into play as these areas tend to remain damp for longer.

To get a good level of control, you in the beginning you will need to spray the Hydrocotyle as well as carrying out the above.

You can control Kurnell Curse by using non-selective herbicides like Roundup (or generically known as glyphosate).

Choose the right herbicide for your turf type and use these in the late spring and autumn when weeds are small and the weed is growing. Herbicide effectiveness is reduced as weeds mature.

Indaziflam (Specticle), and Isoxaben (Gallery) are pre-emergent herbicides that provide some control of Dollar Weed in warm-season turfgrasses, but are not currently registered for this in Australia..

You will need several herbicide applications, as one application will not deal with this weed.