AusBonsai

Hi guys,

Not long had this acacia. Can't work out if it's over watered or under watered?? Any ideas? End of branch the leaves are yellowing and dying off... Water when topsoil is dry but nit sure what's happening deeper in the pot. Sydney south.

Cheers Mitchell

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Hi mitch_28
It very well could be over-watering.
I tried working with an Acacia cognata once and struggled with it for 18 months before it finally died.

The foliage would slowly die back from the tips and smaller branches would defoliate and die.
Everytime i watered the tree, it seemed to stress it.
I placed the tree in an out of the way spot and literally forgot about it.
When i remembered a couple of weeks later, i was supprised to find the tree had started to bush up nicely,the foliage looked good and its overall appearance had picked up.
Once established,these trees LOVE dryness!

Id let the top of the soil dry but there must have still been moisture in the bottom of the pot.
I believe this is what was causing my problems (its a real balancing act when an Acacia is grown in a bonsai pot).
Acacia are almost like cacti in that their soil needs to dry 100% between waterings.
Re-watering whilst there is still moisture in the pot can cause all sorts of problems.
I learnt the hard way!
It may be something else BUT the number 1 problem that is experienced by growers,that have an Acacia in a container/bonsai pot, is over-watering... not allowing the soil to dry out completely between waterings.
Treat your acacia like a cacti...they LOVE neglect (hard to do in the "caring" world of bonsai).

Whilst I would not over water them, regular and consistent watering is essential. If they miss the watering a few times they may suddenly yellow and die. However in this case a more likely problem is too much, or too little fertilizer.
Dennis Mc

A few questions how often do you water it. What soil type is it growing in. How large small is the container it is growing in. Where is it positioned in the garden shade full sun etc.. also you say you have not had it long is it a tube stock or established older plant from someone? I don’t see lack of fertiliser causing this. You haven’t mentioned if you have fertilised it? All of these questions answered will help.
A picture of some foliage doesn’t give enough information for a correct solution.
Mine is in a large cascade pot, well draining soil mix in full sun. During winter only gets watered once a week or once a fortnight pending on if we get rain or drizzle. In warmer weather gets watered twice a week unless temps hit high 30s then three to four times a week.

Cheers
Kirky

By now you'll see that diagnosis is far more than just what's happening to a few leaves. Often different causes can bring on similar symptoms so the background info is vital to get better results.
I note that you haven't had it long so probably don't know the state of soil and roots. You can usually gently turn the root ball out of most nursery pots without disturbing roots or soil and check what's going on down there.

While too much water can be an issue so can not enough and I find that's much more common through spring as the plants start to grow and demand for water is high. If the soil is getting full of roots there's less room for water in the pot and the tree gradually gets drier and drier despite regular watering so it is important to know how well the water is penetrating. Wood skewer or chopstick is good as a soil moisture monitor. Push deep into the root ball and leave it there. Pull out each day to get a far more accurate picture of what water is really doing below the surface.
If centre of root ball tends to stay dry you may need to water the pot by soaking overnight every week or 2 to ensure proper wetting. If that's the case also plan on repotting soon. It's probably already Ok to do natives in Sydney.
If the soil moisture meter shows the soil is still wet internal obviously water less often to compensate.

Let's hear about the other factors people have asked about but also try for a better measure of soil moisture please.

Thanks for the replies everyone. I'll post another photo I found from a few weeks back. I've probably owned it for about 6 weeks maybe after purchasing from Bonsai South in Sydney, tag says 2017. Ok so on top of any rain we've had I would say it's watered a couple of times a week. As mentioned, due to top soil being dry and having a nice big drainage hole on the bottom of the pot, I assume ( obviously not a good habit for bonsai survival ) the tree needs more water. I've not feed the tree since owning apart from liquid tonics ( seaweed etc ).
It's kept out in the open with sun from around before lunch to late arvo. Heaps of big trees around home so not full sun all day for any plants here. As for roots and soil I don't know. Not sure when it was repotted last and it would be in a commercial grade bonsai soil that could possibly have some extra grit mixed in but also don't really know.From Kirky above, it would seem to me maybe too much water and maybe lack of food coming into Spring.
As it's raining again, that's more moisture and that's on top of the soaking in a tub yesterday ...... Oh dear
I'll do the skewer test in future but maybe should let it dry out a bit and inspect under the soil line to get a better picture. Hope this clears a few questions up.
Thanks again all

Mitchell

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I see the pot is big so less likely lack of water is the problem. More likely stays too wet with that sized pot and a relatively small tree. Definitely check with a probe (skewer) to monitor real moisture levels.
Possible sunburn if the tree was kept in shade before (as is often the case in nurseries). Moving shade adapted leaves suddenly to sun can cause sunburn but as you have tree cover providing shade and it has been a few weeks leaves should have adjusted by now.
Fingers crossed it can recover from here.

Thanks for the info it helps. My money is on either needs a repot or too much water. When you skewer it to check for wetness just poke about with the skewer to see how solid the mix is. If its like concrete it could need a repot and that could also be a problem where water is not being absorbed due to being pot bound.
With all the rain it won’t need extra water, they are great trees mine is currently flowering.
Cheers
Kirky

Thanks for the replies.

Yeah I think that the consensus is that its a combination of too much water and possibly some sunburn as I did bring home and put it straight out in the open. Hopefully with some time all will come good. Will wait a touch longer ( bit warmer weather and dryer mix )before inspecting the roots. If I leave a skewer in the pot will it dry out at a similar rate to the mix??
Never owned natives so everyday is a school day!

Regards Mitchell

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I bought an angophora in a large nursery pot last year, watered it regularly, and it even grew fairly well, but this past week I decided to repot it and discovered that the majority of the root ball was dry, even after lots of rain. The mix this nursery used is very fine and has so little non-organic matter that it dried out internally and never got damp again, by the looks. The nursery has massive overhead sprinklers, so it probably got just enough to keep it alive.

There really is a lot to say about cleaning out fine sandy nursery mix asap in my opinion.

This may be totally different to your situation, but I thought I'd mention it in case.

another good way to check wether a large pot is drying out enough is to check how heavy it is. A large ceramic pot like that will have a fair bit of weight to it, but if you lift it and it feels extremely heavy, there is a good chance the soil is waterlogged and not drying out. If you lift it and it feels unexpectedly light, it may have become water repellant and not absorbing any water. As Mel mentioned with her angophora, nursery mixes with high organics and bark based mixes can get so dry water just runs around the side. Especially if full of roots.

I tend to find coming out of winter, or sometimes the middle of winter where I live as its usually fairly warm and sometimes windy, that I need to check that pots aren't hydrophobic. I grow lots of trees in nursery pots and bark based mixes and an occasional lifting of a few pots lets me know whether my watering is keeping up with plant needs, or I need to wind it back a bit.

Certainly Sydney had been dry (low humidity too) and windy lately.

Fairly typical spring weather.

I bought an angophora in a large nursery pot last year, watered it regularly, and it even grew fairly well, but this past week I decided to repot it and discovered that the majority of the root ball was dry, even after lots of rain. The mix this nursery used is very fine and has so little non-organic matter that it dried out internally and never got damp again, by the looks. The nursery has massive overhead sprinklers, so it probably got just enough to keep it alive.

This is exactly the scenario I mentioned above. I've seen it lots of times. Not only from fine mix either. Many natives grow lots of fine roots. Banksia is one of the worst offenders down here. All those fine roots eventually fill the spaces no matter what sort of mix they are in. By then there's no spaces for water to penetrate and the roots keep taking more every day so eventually the centre is dry and gets drier day by day because watering only wets the sides of the root ball. When weather gets hotter and plants need more water something must give and it is usually the plant. Banksias did so much better here water I started to repot each year to allow for more roots.

If I leave a skewer in the pot will it dry out at a similar rate to the mix??

Definitely leave the skewer in the pot. The soil is not a cake so the skewer needs time to absorb any moisture to give a good indication. Each day just pull it out and check the bit that was deep in the soil. It should be a similar moisture content to the soil - damp means don't water, dry means water now. Poke it back in after checking, ready for the next day.

another good way to check wether a large pot is drying out enough is to check how heavy it is.

You can certainly get a feel for the weight and I use that method too but for that to be accurate you really need to have a good idea of how heavy the individual pot is with and without water. Without that background knowledge weight can be meaningless.

So to update, I purchased a moisture meter from a reputable shed and stuck it in.....
Well the dial almost did a full 360° on a 5° scale so mix is very wet.

melbrackstone wrote:The mix this nursery used is very fine and has so little non-organic matter that it dried out internally and never got damp again, by the looks. The nursery has massive overhead sprinklers, so it probably got just enough to keep it alive.

There really is a lot to say about cleaning out fine sandy nursery mix asap in my opinion.

This may be totally different to your situation, but I thought I'd mention it in case.

The mix is also an organic mix with very little non organics and plenty of small sandy particles.

I've been trialling my own mix using the woolies cat litter, sifted into 3 grades and only using the medium size grade, mixed with a small amount of bonsai soil. Maybe I'll do a repot into similar and see what happens. Can also inspect roots at same time.

Should I just do it now even though mix is saturated or wait a few days for it to dry out ( which it may not anyway ), probably answering my own question....

Picture of another pot with my mix for effect.

Appreciate all the assistance

Mitch


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I've never repotted an acacia, so can't say how much to take off, but I'd certainly be trying to get it out of the pot soon to get a look at the condition of the roots. Have you spoken to the guy you bought it off? They might have some pointers to help a successful transition.