A Successful Weeding Solution for Bonsai
I hate weeds, plain and simple. I particularly hate weeding with a passion, I find it to be a waste of time that I could have spent styling or working on my bonsai. I am however a big advocate of regular feeding of bonsai, to the extent that over the last twelve months I have been feeding my bonsai weekly with impressive results (more on that soon).
With a high feeding program come weeds, and lots of them. They are tenacious and I have tried unsuccessfully for years to find a solution that works and is sustainable without harming the bonsai. That is until Alex Bennett put me onto Organix Weed Blitz by Amgrow (thanks mate, I owe you big time for this one!)
About Organix Weed Blitz
Amgrow describe Organix as “a new generation, wholly plant derived, knockdown and pre-emergent herbicide.” Organix Weed Blitz is BFA (Biological Farmers of Australia Ltd) certified as organic, is made entirely from plant source, is PH neutral, does not harm soil microbes, leaves no residual in soil and has no harmful impact on insects (including bees), birds and earthworms. AMAZING!
Organix Weed Blitz is a new generation organic herbicide that is made from pine oil extracted from Australian and New Zealand pine (136g/L Pine Oil). It works by stripping the coating from leaves, stems and even seeds that it comes in contact with, causing cells to collapse.
Organix Weed Blitz is a non-systemic herbicide, so it will not have an effective on woody plants or plants with runners, rhizomes (underground runners) or tap roots because the natural plant oils do not penetrate woody stems or roots. AKA, bonsai friendly when used correctly. Warning: DO NOT SPRAY ORGANIX ON BONSAI LEAVES (sorry for stating the obvious). 
Testing Organix Weed Blitz
I’ve been testing Organix Weed Blitz for the last month and I would go as far as saying that I am ecstatic with the results. Finally someone has come up with an effective weed killer that is safe to use around bonsai nebari.
During the testing process I have used Organix around the bases of a wide variety of trees including Conifers (Black Pine, Shimpaku, Prostrata, Procumbens, etc.), Ficus, Maples and Elms. None of the bonsai have shown negative effects from the correct use of Organix spray. Even those who have had some contact on their leaves have shown only localized effects (see images below).
Organix is really easy to use. The only real consideration is not to use it two hours before rain. It comes in an easy to use 750ml spray pack that retails for around $11 (AUD). It has a soapy type smell that is obvious but not offensive. The smell starts dissipating after about 24 hours and lasts for a few days.
I’ve found the effect of Organix seems to amplify when in sunlight. Weeds sprayed in the evening will show moderate impact overnight then a dramatic result once they are in the sun for only a very short time. Interestingly the packaging does say that it works best in warm sunny conditions. Below are the results of the tests I have run over the last month.
Test one: Corky Bark Elm
Pre Organix Weed Blitz spray. I have left this Bonsai way too long for weeding so it was the perfect test case.
Only 4hours after spraying Organix Weed Blitz there are some amazing results. I was really surprised how fast the weeds started dying back.
One week later every weed is dead!
One month later we are still weed free!
Test two: Satsuki azalea
This small Satsuki azalea bonsai was persistently covered with weeds
After spraying with Organix Weed Blitz 
Still no weeds one month after Organix
Evidence of the dead weeds
Test three: Ficus
I have found leaves that come into contact with Organix have a localized effect. You can see the burns on the fig leaves, however, the damage is localized to only the area contacted. The demarcation line is quite impressive.
Taken a few hours after spraying (8:22am). Interesting to see the fig leaves are affected very quickly. You can see the weeds and moss on this mame bonsai are still unaffected
Six hours later you can see the weeds are dead. (2:40 pm) 
Two weeks later the overall health of this small, mame size fig, is unaffected by the weed killer, all leaves from the spray are relatively unchanged.
Test four: Moss
I do not consider moss to be a weed, however, I did want to assess the impact the weed killer would have on the moss. These images show how significant the localisation of this product is. A test on the moss shows very clearly defined lines where the spray has landed and absolutely no creep beyond that point of impact.
It’s reassuring to know the effect of the spray does not spread beyond where it lands and something as delicate as moss is not effected beyond the spray line. 
Test Five: Seedling
This is a stray seedling from an Angophora tree that sits behind my bonsai. I deliberately used it to test the effect of the spray. After complete saturation you can see that only the very youngest part of the seedling was effected. For all intents and purposes the woodier parts of the seedling were unaffected.
Test Six: Difficult root system
This is one bonsai that has been extremely difficult to keep the weeds out of. The nooks and crannies of the roots around the rock make it almost impossible to get all the weed roots out. Even working really hard on weeding this tree has seen disappointing results in the past.
You can see that after months of solid work, when left for a few weeks this is the result I would normally get.
This is the same tree four weeks after Organix. No weeds at all.
Another bonsai with difficult roots to weed and another Organix success. 
Completely weed free for the first time in 20 years!
Another example of decimated weeds
Weed free bonsai! Woohoo!! 
Weed identification
I’m no horticulturalist (not even close) but after some research I think I’ve come up with some names of the weed I commonly see on my bonsai. I must say finding some of these was really difficult and I’ve come to the conclusion there are probably many genetic variants of these weeds.
Procumbent Pearlwort
I literally hate this stuff. Of all the weeds in my bonsai this is the most tenacious and my number one most annoying bonsai weed. It took me a while to work out exactly what it is. At first I had incorrectly identified it as Irish Moss (Sagina subulata) but I’m sure it is actually Pearlwort.
Gone! The good thing is Organix Weed Blitz smashes pearlwort weed
Unidentified annoying weed sent to us from the devil
This weed has been the hardest to formally identify and I’m still not sure exactly what it is. Possible identification includes a variant of Anagallis minima (Chaffweed), Primulaceae (Scarlet Pimpernel), Chamaesyce maculata (Spotted Spurge), or Stellaria media (Chickweed). If you’re reading this and you have any other suggestions please let me know because I have literally scoured the internet for this one.
Regardless of what it is, it’s tenacious and annoying. It is another one that came to my collection on a bonsai I was looking after for someone.
I think this weed most closely resembles a variant of Chaffweed (Anagallis minima).
Creeping Oxalis (Oxalis corniculata) / Creeping woodsorrel
This weed resembles a small clover. It can be green or a deep purple colour with small yellow flowers. It sends out runners and roots that snap easily so it’s very hard to completely remove.
Cudweed (Aamochaeta galviceps)
This is one of the flat weeds I sometimes get. Again, it’s not too hard to control by hand but it will be nice to see it gone for good.
Spotted spurge – (Chamaesyce maculate)
This is another weed that I have had problems with in the past, however, it was not too hard to control by hand. That said, even when you think its gone it will show its head when you’re not watching.
The great thing is all these weeds have been absolutely smashed by the Organix Weed Blitz. This is possibly the most satisfying result I have had from any product. I hope this article has been helpful for those struggling with the battle of the bonsai weeds.
Matt
Disclaimer
Disclaimer: The content contained within Matt’s Bonsai Blog has been provided in good faith and should be considered a general source of information only. This is not a commercial website, Matt’s Bonsai Blog has no paid advertising and there is no commercial relationship with any of the companies, products or people mentioned. Positive recommendations for businesses and/or products are based on personal opinion and a genuine belief in the products or services offered by those mentioned. The information provided does not express the opinion of others or any manufacturers mentioned. All due care is taken when compiling this information, however, Matt’s Bonsai Blog does not warrant that this information is accurate, free from omissions or up-to-date including any recent changes. The content does not take into consideration your personal circumstances. You should make your own independent assessment of the information provided and you should not rely solely on this information when making decisions.
References and good sites for weed identification
Amgrow
General weed identification
Australian Government – Identifying Weeds
Australian National Herbarium – CANBR and ANBG databases
Procumbent Pearlwort
Google Images – Procumbent Pearlwort
Discover Life – Procumbent Pearlwort
Anagallis minima (Chaffweed)
SEINet – Anagallis minima (L.) Krause – Family: Primulaceae – Chaffweed
Go Botany – Lysimachia minima (L.) U. Manns & A. Anderb. – chaffweed pimpernel
Chamaesyce maculata (Spotted Spurge)
Google Images – Spotted Spurge
Brisbane City Council Weed identification tool – Spotted Spurge – Chamaesyce maculata
Primulaceae; Scarlet Pimpernel (Anagallis arvensis)
Anagallis arvensis – Primulaceae (Primrose Family)
Wikipedia – Anagallis arvensis – Scarlet pimpernel
Stellaria media (Chickweed)
Wikipedia – Stellaria media – Chickweed
Oxalis corniculata (Creeping Oxalis) / Creeping Woodsorrel
Lawn Solutions Australia – Creeping Oxalis – Oxalis corniculata
Creeping Woodsorrel – CABI – Invasive Species Compendium
Wikipedia – Oxalis corniculata – Creeping Woodsorrel
Matt's Bonsai Blog 