Mark Vette – Internationally renowned Animal Behaviourist, Educator, Author and TV personality

Handling the Deadly Karaka Berry Season


Training techniques to help protect your dog from deadly karaka berries

Karaka trees fruit from January to April, and the ripe berries are highly toxic to dogs, and can easily be fatal.

This is especially important information for new dog owners, who may not be aware. I’ve heard too many tragic stories of people losing their much-loved dogs, so please share this article with the dog owners in your life.

What are karaka trees?

Karaka trees are an evergreen native tree found all over New Zealand. They are common in nature reserves, parks and urban areas.

During the months of January to April, karaka berries will ripen, turn from green to orange and fall off the tree. These berries are sweet-smelling and can be very appealing to dogs, but the kernels are highly toxic and can be fatal if eaten.

The fruit will still be toxic even when it has fallen off the tree and dried up, so you need to be vigilant about shrivelled dry fruit on the ground as much as the fresh berries.

Here are some photos to help you identify Karaka trees in your area or on your regular dog walk.

How to recognise Karaka berry poisoning 

Symptoms of karaka berry poisoning can include:

  • Weakness
  • Vomiting
  • Confusion
  • Back leg paralysis
  • Convulsions

Symptoms can be delayed 24-48 hours.

If you see your dog eating karaka berries, or even think there’s a possibility they might have – go to the vet immediately or ring them for advice.

If your dog shows any of these symptoms, go to the vet immediately. 

How to prevent karaka berry poisoning 

By far the safest option is to keep your dog well clear of karaka trees during the fruiting season. Take note of any karaka trees in your local area, I suggest doing a loop around your normal dog walking routes taking special care to look out for karaka trees that could drop fruit in a place where your dog could access them.

Then you can either avoid those areas, or make sure youre watching your dog VERY carefully when nearby.

If your dog is one to scoff anything they find without too much warning (labs, I’m looking at you!), then you may want to consider a muzzle to be safe.

I have also listed some training techniques you can use to put your dog off eating these berries. Though please keep in mind these techniques are not 100% reliable, you will still need to be very vigilant.

Discrimination Training

You can use a technique called Discrimination Training to put your dog off going near karaka berries. This is a technique that teaches your dog what they are allowed to chew or touch (dog toys) and what they aren’t (e.g. shoes, house plants, karaka berries). 

The way we do this training is designed to teach your dog to steer clear of banned items, even when you’re not around.

Please note you need to use utmost caution when doing this training with karaka berries. Do not risk your dog eating the berry.

How to do it

We do this with contrast training, there is both a reward for steering clear of the berry and a consequence for going too close to it. The contrast helps your dog learn more quickly.

Have your dog on a long lead and slip collar, and arm yourself with a clicker and high value treats (like small pieces of cooked chicken, cheese, dog roll etc).

Lay out some dog toys and a karaka berry or two. Consider putting them in a sealed container with holes in it (e.g. a strawberry punnet taped shut) so that your dog can’t actually eat the berry but can clearly smell it.

If your dog goes for the dog toys, you can praise him and click and reward with a high value treat.

If he goes for the karaka berry, just as he gets close to touching it you give a snappy effective check using the lead and slip collar (description of this at the bottom of the article).  You don’t give any commands, as you want it to appear as if the berry itself delivered the correction, not you. In this way we replicate the way a dog would naturally learn (apparent natural consequence) what to chew and what to avoid in the wild: “This berry “nips” me, steer clear”.

As soon as your dog comes back to you for safety, you click and reward.

By doing this, you teach your dog to avoid karaka berries even when you’re not looking.

If doing this training, it is extremely important that:
– You are unassociated to the correction. Your dog must believe that the karaka berry gave the correction, not you. Stay silent and act totally uninvolved.
– The effective check is firm enough to work. You need to be pretty snappy with it. Keep in mind that putting your dog off touching these berries could save their life. Do it firm enough first time around to be successful.
– Do not allow your dog to eat the berry

You may need to do a few sessions. We want to see your dog avoiding the berry altogether after doing this training.

Please note this is NOT FAIL PROOF. You will still need to carefully monitor your dog when karaka berries are around, it is not worth taking a risk. But it helps reduce the odds.

For those more risky dogs we have more sophisticated tools to achieve this in our Behaviour Clinic, so if you’re anxious about this then flick us an email on 

Teaching the Leave It command 

Discrimination Training is the primary technique to use to put your dog off touching karaka berries. But having a good Leave It command is also very worthwhile. This way if you’re out and about and you spot your dog taking an interest in a karaka berry, you can give a firm Leave It command. However, teach the discrimination training first before the Leave It and NO, so the association of the check is being made with the berry.

It is easier to teach the Leave It command in conjunction with the NO command using the technique below – two very important commands to have working properly. 

The Leave It command is taught by teaching our dog that they can do what we allow them to do, but must leave alone what we tell them to leave alone. This is incredibly important if you imagine a situation in which you see your dog about to eat something dangerous or poisonous – and you can command Leave It.

The No command is taught by using an effective check in conjunction with a firm NO when your dog is doing something you dont want them to do. This quickly shows the dog that NO means stop immediatelyotherwise a negative consequence follows. Use the discrimination training technique first before the Leave It command. 


To teach Leave It & No command 

First set your dog up on their slip collar with a long lead attached. Using a long lead for this training enables you to give a remote correction, that is, an effective check (description below) to tell your dog that the behaviour is not acceptable from a distance. Note for this training session, we are not using real karaka berries, we are using something else to teach what “Leave it” means. 

  • Start with some Joining Up, then mentally divide the room into two halves, with one half of the room for ‘good treats’ and the other half for ‘bad treats’ (the same food treat, but your dog isn’t allowed them). Lets say the left half is for good treats, and the right half is for bad treats. Your dog is allowed the good treats, but not allowed the bad treats.
  • Throw a treat into the left side of the room, and tell your dog to Get It in an up-tone of voice. Click and reward your dog for getting the good treat.
  • After about five or so repetitions of Get It, next throw a treat into the right side of the room, and tell your dog to Leave It in a more firm tone of voice. If they leave it / look up at you, click and reward. 
  • If your dog doesnt immediately respond to Leave It by leaving the treat alone, give them an effective check at the same time as a firm No command. 
  • Continue as above, doing good treats (Get It) and bad treats (Leave It) as above. 
  • Only do it as long as the dog isnt getting confused. 3 – 4 repetitions is often enough for the first session.

By doing this, you are teaching both the Leave It and No commands simultaneously. The real point of the exercise is to get  an opportunity to reinforce that No command as it’s so important, and by doing so you also teach the Leave It at the same time.

If your dog is too responsive and leaves the bad treats every time just by the way you’re using your voice, increase the value of the treat you’re using (and do this training with them hungry) to make it really hard for them to leave it alone. You do have to set them up to fail a bit, so that you get an opportunity to reinforce that No command. 

If youve got your dog performing consistently while in a distraction free room, test your training in a different space with different items (such as toys) to proof your dog for other circumstances. 

Effective Check Description

An effective check is a technique used for deliver a correction to a dog for inappropriate behaviours. This will always be followed by a click and reward when the dog stops the undesirable behaviour or avoids the banned item.This is used when you need to tell your dog not to do something. To give an “effective check” you fit your dog with a safety slip collar attached to a lead. See below for images of a slip collar. When they act inappropriately, quickly snap the lead in a firm and swift upwards or sideways motion to briefly tighten the collar around the dog’s neck, then release. Do not continue pulling on the lead and tightening the collar. We are not trying to harm the dog, but we are trying to create enough discomfort to interrupt the undesirable behaviour so that it stops. A check has been effective if it stops the dog’s behaviour; if you are delivering a check and it’s having no effect, you need to be firmer (or you are not using the right technique). Big strong dogs will need a much firmer check for it to be “effective” than smaller or sensitive dogs. A check is ideally applied remotely (at a distance) in most situations, by using a long-lead or retractable lead, so that the correction is not associated with you.

We always contrast a correction like an effective check with positive reinforcement for the RIGHT behaviour (a click with a clicker, followed by a high value food reward) when they move away from the check and the apparent cause of it. Dogs learn best by contrast.

Want more guidance?

If you’d like more guidance with this training, join one of our Virtual Schools. We cover these techniques with videos showing you exactly how to do it, so you can be sure you’re getting it right. We also have Live Coaching Sessions each week where you can ask questions, and my trainers are on hand to help out any time you need. Check out our courses here.

Hope this helps!

I hope this helps you to feel confident about protecting your dog during karaka berry season.
Please share with all the dog owners in your life, especially new dog owners who may not have heard of this!

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