Carrot Weed (Parsley Dropwort)
Oenanthe pimpinelloides
DESCRIPTION
Parsley dropwort is very often known as ‘carrot weed’ although it is not closely related to the wild carrot species.
It is common in Northland and South Auckland, but also exists in other North Island locations. It grows in pastures as well as waste areas, roadsides, disturbed ground, sports fields and lawns.
Parsley dropwort or carrot weed is a perennial weed, and can be highly invasive when growing in its preferred conditions. It grows very aggressively in pasture, where it is a serious problem because stock will not eat it due to its unpalatable taste. This lack of palatability is especially the case when the plant forms upright flower stalks in late spring.
In appearance, it is a parsley-like plant, spreading from a central stem, and reaching a height of 30-90 cm. The leaves grow on stalks in a rosette arrangement, with opposite leaflet segments, appearing much like the herb parsley (hence the name). The flowers appear in spring at the top of the taller flower stalks, in small clusters (umbels) of individual white blooms about 4mm diameter. The flowers appear from October to April.
The roots of parsley dropwort (carrot weed) have small black tubers towards the ends. These tubers can enable regrowth of the plant following control attempts.
Inclusion of parsley dropwort (carrot weed) in hay will lower the quality of the hay, and is also responsible for the spread of the weed to further locations if the affected hay is sold and transported.
The sometimes-confused wild carrot is not similar at all, and is distinguishable by its leaves, which are almost identical to those of the common vegetable garden carrot.
It might also be confused with the hemlock, which has similar white flowers on umbels. However, the hemlock has leaves that are distinctly fern-like in shape.
HERBICIDES TO CONTROL CARROT WEED
The only effective method of control of parsley dropwort or carrot weed is with herbicide. Boom and spot spraying are commonly used, but there is very good potential to use wipers after late spring, when the carrot weed (parsley dropwort) is taller than the pasture.
Herbicide to Kill Carrot Weed - Spraying
- Rainbow & Brown 2,4-D 720 Amine sprayed by boom at 2.5-3L/Ha Will kill younger plants, applied in autumn, early winter or early spring. Note that in Northland, from 1st September until end May, you cannot apply the ester version of 2,4-D but our less volatile amine version is fine.
- MCPA750 - If you have a paddock with lots of buttercup as well as parsley dropwort (carrot weed), then MCPA750 seems to kill carrotweed nearly as well as Rainbow & Brown 2,4-D 720 Amine and both are quite good for thistle control, especially when younger. MCPA750 will knock your clover around a bit more though.
- MSF600 sprayed by handgun at 30g/100L water, plus 100ml SuperWetter penetrant, is effective in waste areas where pasture grass damage is not an issue.
- Glyphosate360 sprayed at 4-5L/Ha by boom for cleaning out prior to pasture renewal or cropping, will also take out the parsley dropwort present. If using Glyphosate 540 then the rate is 2.7L-3.5L/Ha.
- Clopyralid 300g/L sprayed at 100ml/100L water is an effective spot spray treatment and can be sprayed over pasture and ornamental grasses, although it will damage clover. It also requires a certified handlers certificate to purchase.
Herbicides for Weed Wiper Control or Carrot Weed
We are great fans of using weed wipers as often this is the most cost effective way or removing hard-to-kill erect weeds, so if terrain permits wiper operation then use:
- MSF600 at 2g/L water and Glyphosate360 at 1L per 2L water or Glyphosate 540 at 660ml/2L water or Granny granular glyphosate at 450g/2L water
Note: The small tubers on the roots of parsley dropwort (carrot weed) can enable it to regrow after control attempts, and it is therefore not realistic to expect permanent eradication from a single treatment. Follow-up treatment of regrowth will be necessary.
