Hairy Bittercress (Cardamine hirsuta).
Hairy Bittercress is also called Bittercress, Swinecress and Flick Weed. Bittercress is a Winter annual broadleaf weed and is a member of the mustard family. For more information, please check out our weed ID chart.
Bittercress is a good indicator weed of poorly drained, wet soils, and often is found in disturbed areas.
After you finish reading this, you will be able to:
- Identify Bittercress, Swinecress and Flick Weed.
- Know the habitat of Bittercress, Swinecress and Flick Weed.
- Know the best cultural and chemical options to control Bittercress, and Flick Weed.
Why is Bittercress a Weed?
- Produces a large number of seeds.
- The seeds germinate immediately or stay dormant for several years.
- The seeds are sticky so disperse easily.
- In a moist environment like the Southern Hihlnads of NSW, this weed germinates, and grows at any time of the year.
- Bittercress is a host for aphids.
Hairy Bittercress is typically one of the first weeds to appear in the Spring, but it can grow all year-round when suitable conditions exist.
The distribution map is courtesy of The Living Atlas of Australia.
Bittercress Identification.
Flick Weed is a weed in the ACT, NSW, NT, QLD, SA, TAS, VIC, and WA.
Category: Bittercress is a broadleaf (Dicot) weed.
Photosynthetic Pathway: C3 Weed.
Flower: The white flowers are tiny with four white petals, and are around 3 mm long.
Height: Bittercress is a Slender annual herb that grows to a height of 35 cm.
Leaves: Flick Weed has thin, sparsely hairy leaves that form a rosette at the base. These leaves have 1 – 7 leaflets, and the side leaflets are circular with the terminal leaflet being kidney shaped. On both sides of the leaves are numerous tiny hairs.
Reproduction: Bittercress forms lime green seed pods up to 25 mm long, that flick the seeds out when ripe. These seeds travel 1-2 metres from the plant. Each plant produces up to 5000 seeds that can germinate immediately. However, if conditions do not favour germination they can survive for several years
Comments: The seeds of Bittercress tend to germinate in the Autumn or Winter, and are mainly dormant in cold weather. They resume their growth in the Spring when they then produce more seeds. It has a 12-week lifecycle.
Habitat: Bittercress is widespread weed inhabiting most gardens and thin lawns. It is common in damp, sunny or disturbed soils.
How to Remove Bittercress from your Lawn.
Cultural Control of Bittercress.
- Prevention is the best way to manage Bittercress.
- Hand weeding is very effective to manage small populations but you must repeat this regularly. It is also important that you do this before it flowers, because the seeds can still disperse when you handle the plants. Once you pull Bittercress up, remove it from the area and dispose of it.
- Bittercress seed tends to not germinate in the presence of competitive or shading vegetation such as dense turfgrass. This means that selecting the correct turf grass and turf seed for you site is important.
- Proper fertilizing, mowing, and watering will encourage turf growth and reduce the chances of weed establishment.
- If you frequently mow in the Spring, this removes Bittercress flowers before seeds develop. However, be aware that as this weed grows from a rosette it can tolerate mowing over a wide height range.
Chemical Control of Bittercress.
Several post-emergents are available to control Bittercress with treatment being best over the entire area rather than spot treating.
Pre-emergents for Bittercress.
Currently only BASF Freehand and Pendimethalin (ProForce Battalia 435 Herbicide) are registered for Bittercress or Swinecress use in Australia.
In the US pre-emergent options include: Dimethenamid-P + Pendimethalin, Indaziflam, Oxadiazon, and Dithiopyr.
Post Emergents for Bittercress.
Post emergent options include:
- 2,4-D.
- Warhead Trio. Safe on Buffalo grass.
- Contra M herbicide. Do not use Contra M on Buffalo grass.
- MCPA.
- Weed Blast MA. Safe on Buffalo grass.
- Dicamba. Don’t use Dicamba on Buffalo grass..
- Quali-Pro Negate.
Rate Table for Post Emergent Bittercress Herbicides.
Product | Active | Chemical Group | Rate/Ha | Comments | ||||
2,4-D | 2,4-D | 4 | 1.8-3.2 | Wet foliage thoroughly. DO NOT mow lawn for 1 week before and at least 1 weed after application. DO NOT use on Buffalo grass (WA only). | ||||
MCPA | MCPA | 4 | 930ml -1.8L | Apply in high volume to actively growing weeds. DO NOT mow for 2 days before application. Some transitory damage may occur to fine turf grasses | ||||
Dicamba | Dicamba | 4 | 1.2L + 3.2L of 2,4-D Amine 625g/L | Use a minimum of 1000L/Ha water. Do not spray on Buffalo or Bent Grass. | ||||
Negate. | Rimsulfuron + Metsulfuron-methyl | 2 | 110g | Apply to growing weeds and not to stressed weeds. | ||||
Weed Blast MA. | Bromoxynil + MCPA | 6 + 4 | 3-6 L | Apply in a minimum of 500L/Ha water. DO NOT mow for 2 days after treatment. | ||||
Warhead | MCPA + Clopyralid + Diflufenican | 4 + 12 | 5 L | You may see discolouration on kikuyu, carpet grass and Queensland blue. Avoid overlapping. Use an NIS. | ||||
Contra M. | Dicamba + MCPA | 4 | 6.5 L | Apply in 250-400L water. DO NOT use on Buffalo grass. After use do not mow for 2 days before or after application or fertilize within two weeks. | ||||
Non Selective Control of Bittercress.
- Glufosinate-ammonium provides control for 4 to 6 weeks, but Bittercress or Flick Weed but it regrows due to the limited movement of glufosinate.
- Glyphosate. You can use Glyphosate but if water quality is an issue then use ProForce Manta Ray.
The following are non-selective but also have a long term residual and stop re-growth of Bittercress.
- Renegade. Renegade stops seed germination for up to 12 months, and reduces the need for multiple herbicide applications.
- Numchuk Quad. This gives effective post and pre emergent Flick Weed control for up to 12 months.
- Cortex Duo. Cortex Duo gives a rapid knockdown of Bittercress, and residual control for up to 3 months. It is also safe to use around trees.
