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NZLA Blockade (250ml) Herbicide (Barricade Herbicide)

$115.00 ea

Purchase this item and earn 12 NZLA Points


Blockade is a selective pre-emergent herbicide that provides residual control of weeds in established turf. This is commonly known as Barricade in New Zealand. NZLA is the only supplier of this product in smaller pack sizes in New Zealand.

Blockade Herbicide controls susceptible weeds by interfering with cell division in the root tips of newly germinated weeds.

Blockade contains 480 g/L Prodiamine in the form of a suspension concentrate (SC).

What established turf can Blockade Herbicide be used in listed;

  • Bahia Grass (Paspalum notatum),
  • Buffalo Grass (Stenotaphrum secundatum),
  • Carpet Grass (Axonopus affinis, Axonopus compressus),
  • Couch, Common (Cynodon dactylon),
  • Couch, Hybrid (Cynodon dactylon x Cynodon transvaalensis),
  • Kikuyu (Pennisetum clandestinum),
  • Qld Blue Couch (Digitaria didactyla),
  • Seashore Paspalum (Paspalum vaginatun),
  • Zoysia (Zoysia japonica, Zoysia matrella)


What weeds is Blockade Herbicide registered to control;

  • Barnyard Grass (Echinochloa crus-gali),
  • Crab Grass (Digitaria sanguinalis),
  • Parramatta Grass (Sporobolus africana),
  • Rat’s Tail Fescue (Vulpia myuros),
  • Summer Grass / Crab Grass (Digitaria sanguinalis)
  • Crowsfoot Grass (Eleusine indica)
  • African Lovegrass (Eragrostis curvula),
  • Bahia Grass (Paspalum notatum),
  • Kentucky Blue Grass (Poa patensis)
  • Paspalum (Paspalum dilitatum)
  • Winter Grass (Poa annua)


Blockade Herbicide’s selectivity is primarily through soil profile placement.  Achieving this soil profile placement of Blockade Herbicide correctly is vital to obtain high efficacy.  Applicators should ensure an even matrix flow through the soil profile to achieve a consistent and even zone of herbicide activity.

After application, plants that have the majority of their root system in the herbicide profile zone cannot effectively absorb the water and nutrients required for root and plant development. Therefore, good even coverage and incorporation is required to ensure the weeds cannot recover by establishing roots outside the zone of herbicide activity.

Small seeded plants (i.e. annual grass weeds) are affected more by the herbicide than established grasses as they germinate in the soil profile zone of herbicide placement (i.e. 100% of their germinating root system is affected by the herbicide).

Warm-season grasses can be less prone to root inhibition due to the fact that they have multiple fibrous root systems with established roots beyond the depth of the zone of herbicide activity and are therefore are still able to obtain moisture and nutrients.

Weed control in turf is most effective when Blockade Herbicide is activated by at least 6 mm of rainfall or irrigation before weed seeds germinate and within 7 days after application.

Option to tank mix with Glyphosate to treat gravel pathways and fence lines offering knock-down and pre-emergent in one application for up to 6 months of weed control.

Light post-application irrigation ensures the product is washed off the foliage and moved into the top couple of centimetres of the media providing the opportunity to bind and establish the weed control band.

Pack Size: 250ml & 500ml – For commercial amounts see Barricade 

Application rate 40-80ml/100m²

Blockade FAQ’s

What is NZLA Blockade?

Blockade is an excellent and safe pre-emergent herbicide for control of broadleaf weeds and grasses in warm season turf and garden beds.

What pack sizes are available?

Blockade comes in a 500ml and 250ml pack sizes. We also sell Barricade which is exactly the same product in a 5L.

What is a pre-emergent?

A pre-emergent herbicide is applied to the soil before weeds germinate and emerge from the ground. Unlike post-emergent herbicides, which are applied to actively growing weeds, pre-emergent herbicides work by forming a barrier in the soil that inhibits the germination and growth of weeds.

How does Blockade work?

Blockade works by interfering with cell division in germinating weed seeds, preventing them from developing into mature plants.

How long does Blockade work for?

Blockade, at label rates, will provide control for 4-6 months.

Will Blockade control weeds already present in my lawn or garden?

No, Blockade on its own will not control weeds, however it will stop new ones from germinating. Blockade is an ideal tank mix partner for many post-emergence selective and non-selective herbicides.

Is Blockade safe for pets and children after application?

Once Blockade has dried on the turf, it is safe for pets and children to re-enter the treated area.

When is the best time to apply Blockade?

The best time to apply Blockade is in the spring before weeds germinate or in the autumn for annual winter weeds.

Can Blockade be applied during rainy weather?

It is best to avoid applying Blockade during rainy weather to prevent runoff and ensure proper activation of the product.

Will Blockade harm my plants in my garden?

With a couple of exceptions, no, Blockade is safe to use on its own around many plants, trees and shrubs in the garden. The main exceptions are bulbs and annual flowers. Blockade is a great option for reducing hand-weeding and spraying in your garden for up to 6 months.

How soon after application can I mow my lawn treated with Blockade?

You can mow your lawn treated with Blockade any time after the product has dried on the turf.

Can Blockade be used over mulches in my garden bed?

Yes, recent trial data has shown that Blockade is extremely effective in gardens that have been mulched.

How do I apply Blockade?

Blockade can be applied through your knapsack or boom sprayer, ideally with a large droplet nozzle.

Do I leave Blockade on the leaf or water in?

It is very important that Blockade is watered into the soil and off any mulch within 7 days. This allows the product to form the barrier in soil required to prevent weed germination and establishment.

Will Blockade move in the soil?

No, once watered into the target area, Blockade stays where you put it.

What lawn species can I spray Blockade on?

Blockade can safely be applied to established couch and kikuyu lawns to stop weed invasion for 6 months.

What about cool season grass like Rye, Fine Fescue and Tall Fescue?

Similar products in the USA can be used on cool season grasses, however Blockade in New Zealand is labelled only for warm season grasses.

Can I sow new seed to an area where Blockade has been applied?

No, unfortunately Blockade will stop new seed from establishing. The best option is to wait 6 months and then sow a small amount of seed in a small area to check if the lawn is ready.

Can Blockade be applied to newly seeded turfgrass?

Blockade should not be applied to newly seeded turfgrass until after the grass has been mowed at least twice. However, at NZLA we recommend waiting at least 4-6 months to ensure you do not need to patch or overseed any areas as this will not be possible for six months after using Blockade due to residue activity.

Does Blockade have any specific storage requirements?

Blockade should be stored in its original container in a cool, dry place away from direct sunlight and extreme temperatures.

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