Controlling Weeds in Gravel
Controlling weeds in gravel drives, pathways, garden beds, power sub-stations and railway tracks can be extremely challenging. Once weeds take root, they can difficult to keep away in the long term.
That’s because the types of weeds that grow best in gravel environments tend to have root systems that are the hardest to get rid of e.g. deep tap roots, bulbs, corms, rhizomes or other energy storage organs. The gravel also provides a place for seeds to get trapped and stored ready to sprout when the environmental conditions are just right.
Possible reasons why your weed control is failing
- Metal (stones) used on sites should be 150 mm deep. In many areas this is not the case due to natural soil build-up, maintenance work, vehicle ruts etc.
- Organic matter like leaves and fine material from dust tends build up promoting the growth of weeds.
Terbuthylazine and other pre-emergent herbicide sprays are largely root active. Herbicide applications may only wet upper surface of metalling, meaning that the residual/pre-emergent part of the herbicide is not getting to the soil where seed germination is occurring. Weed shoots that then emerge through the gravel/metalling are not affected by contact with terbuthylazine on stones and so can grow easily.
- Difficulties in getting even application of spray due to site complexity.
Insufficient product being applied.
- Some weeds may be burnt off by spray application but then recover. This could suggest: Antagonism of herbicides; orHerbicide not translocating due to slow growth/metabolism of weeds, or interference of other herbicide; or Not enough herbicide has been applied; or Tolerance to the key active in the herbicide; or Resistance to the key active in the herbicide.
How to Succeed in Long Term Weed Control in Gravel/Stones
- Apply Weed Weapon Preventer at min 200 g per 10 m2. This creates a barrier for up to 3 months that stops new weeds breaking through. It is best applied before rain or before step 2 (i.e. treatment with Weed Weapon Long Term)
- Apply Weed Weapon Long Term at 12.5 ml/L or 125 ml per 10 L (compared to the normal dilution rate of 25 ml/L) and apply to entire site ensuring liquid reaches soil by applying at 2 L of spray per 10 m2 (which is double the normal liquid application rate). This results in the ‘correct’ level of terbuthylazine pre-emergent herbicide per m2. Weed Weapon Long Term both kills existing weeds, and acts as a pre-emergent the prevents new weeds from sprouting for up to 365 days. The application of the diluted Weed Weapon Long Term also activates the Preventer granules which will have fallen through the gravel/stones to the soil below.
Spot treatment of weeds could be also carried out with Weed Weapon Rapid Action or Weed Weapon Invade Gel. Invade Gel would be particularly helpful where weeds are hand weeded and root systems unable to be removed.
Our Weed Weapon Preventer and Weed Weapon Long Term products are both available at all good hardware stores. If you are a commercial operator, farmer, local council or Government Agency Kiwicare can supply large scale commercial quantities. Simply send through an enquiry via our Contact Us form and you'll be connected with our Commercial Sales Team.
Apply Weed Weapon Preventer at min 200 g per 10 m2. This creates a barrier for up to 3 months that stops new weeds breaking through. It is best applied before rain or before step 2 (i.e. treatment with Weed Weapon Long Term)