casaurina yellowing

[pad56]

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[Rory]

Are the needles yellow and brittle? It may have been allowed to dry out too long.

Or are the needles yellow and droopy? It may not be getting enough sun and/or overwatering.

Is it only the needles that are on the upper part of the tree yellow and brittle (crunchy)? This most likely will point to being allowed to dry out, as they very often can die-back to lower areas to allow for survival and now can only support a smaller portion of the tree.

How often are you watering it? Specifically, what was watering like over summer and autumn? If the medium is staying wet for too long, it can be that the mix isn't drying out sufficiently between waterings.
Sometimes what can happen with older stock that isn't regularly repotted, or worked appropriately, is that the inner root ball isn't penetrated by the water and dries out and can slowly die. When you repot older stock, (depending on the species and how often it has been repotted), it helps to remove all the old soil from the inner root ball. This way you allow the root system to easily allow water inside the main root ball. When I first repot old Casuarina stock, I don't remove much of the roots, but more importantly I remove the old soil. Sometimes you have to remove a few roots to pry apart the ball though.

How much sun is it getting? Casys like a lot of sun, at least 2 to 3 hours of strong sun to be in reasonable health.

Is the trunk loose in the pot? You might have worms, ants or the bad guys: curl grubs

[pad56]

thank you Rorry had tree 3 years repoted 6mounths never removed all the soil from roots tree is in grity soil mix is very stable needles are not sagging and dont appear to be dry recently submerged in seasol l water every day always kept same spot gets half sun do you think i should let it dry some or shorten main branches smaller branches further back seem ok

[Rory]

My gut instincts think it may be being overwatered, but in this case its hard to say without really feeling and seeing the mix.

When you say you water it every day, is the soil still wet before you water it?
To test this, over the next few weeks when you would normally water it (you said every day), before you do this can you stick your finger in a good length deep into the pot and if its still wet or damp when you would normally water it, if so then it might be a contributor to the problem.

If in fact it is a combination of problems, just allowing it to dry out more between watering isn't the final solution. If the roots are rotten and/or the mix isn't draining properly then you can repot sooner than later. But I wouldn't take that path yet until you trial that test. Also, when you say its getting half sun, do you know how many hours its getting, as the sun changes direction as the seasons change and whether full sun / part / dappled etc.

Other people might have differing opinions and obviously its hard over the net, but I'm interested whether its still damp if you are watering every day.

[TimS]

Without actually seeing how wet your soil is i would be saying over watering. My black sheoak stays very dry and it is full of energy, they prefer to be on the drier side than the wetter for sure.

[Raging Bull]

I don't think you can make a generalized statement about how much water casuarinas will tolerate. I've seen them in semi-desert conditions in South Oz, and here in Qld they grow on flood plains in semi-swampy conditions. It depends on which variety of Cas. you're talking about. Along the lower reaches of the Tweed River, which is quite salty in the tidal zone, they grow almost to the water's edge in very sandy soil. They seem to be very adaptable with different varieties growing in the different conditions that suit that particular variety.
Just my
Cheers, Frank.

[Rory]

I don't think you can make a generalized statement about how much water casuarinas will tolerate. I've seen them in semi-desert conditions in South Oz, and here in Qld they grow on flood plains in semi-swampy conditions. It depends on which variety of Cas. you're talking about. Along the lower reaches of the Tweed River, which is quite salty in the tidal zone, they grow almost to the water's edge in very sandy soil. They seem to be very adaptable with different varieties growing in the different conditions that suit that particular variety.
Just my
Cheers, Frank.

Yes, both Casuarina and Melaleuca can grow in just about any area In Australia.

However, the question was not posed about why a casuarina growing near the beach, or on a rock face was having problems.
THe question was about this casuarina in the picture above, grown in a pot, and watered daily... in a pot.
I grow cunninghamiana, glauca, littoralis, torulosa, nana and have grown others including distyla, palludosa, verticillata, stricta, and I’ve forgotten the names of others.
I don’t recall any of them exhibiting good health after being over-watered for extended periods of time, particularly if they are also over potted in a POT or have nowhere else for the roots to extend to.

Those that are GROUND grown fair a lot better than potted trees that are over watered because if they are over watered the radial roots sometimes can rot, but the long deep tap roots do not stay permanently wet and often you’ll find the tree is in great health because it doesn’t have to rely on roots that are suffocating.

As Treeman pointed out in a recent post, when we grow trees in a pot, as a Bonsai we often trunk chop, defoliate, cut back heavily and this greatly reduces the water intake it requires. This isn’t the case in a tree growing in the wild.

Allocasuarina littoralis and torulosa are two of the worst species to suffer from over watering.
It mainly depends on the duration of the over-watering.
Allocasuarina glauca is one of the hardiest from overwatering, but if it doesn’t get a lot of sun it will start to decline.

That’s my

[wigarus]

Hi guys,

I am not an expert but I know I'm a panicky over waterer, so to give myself an idea of what the tree needs, I would put the pot in a kitty litter tray, give the tree 1L of water, wait 10 minutes and measure what is in the tray. Then try watering less in mls for a few days. Then I felt a bit more confident to leave them a couple of days between waterings.

[Waltron]

All very odd. I over potted some littoralis' and sat them in water for months during the growing season over a few years and achieved an exceptional amount of growth. I now have only 1 in a bonsai pot and it will take as much water as I can throw at it, all with quite an open mix of course.

The first thing I would usually do is pull it out of the pot and have a look at the soil/roots. Is the water penetrating the root ball? Is it saturated/not draining properly?

[pad56]

days are cooling of up here is this the right time to repot the tree is very old i would hate to loose it she has always liked her water but temperature is getting lower about 12/24

[shibui]

You are correct about this being a very nice looking casuarina trunk. I do hope it survives this problem.

Not sure about in your climate but down south we repot and root prune most natives - including casuarina - in summer when it is warm. They all seem to do far better after root pruning when they are actively growing. Many natives that I have root pruned in the cooler months have done poorly or even died but my 'cooler months' have most nights below 0C.
It may be possible to re-pot natives all year round up there where it is warm all the time.

When I have an urgent (root related) issue I will repot any plant even if it out of normal season. If it is likely to die anyway there is little point just leaving it and watching it die. If repotting even gives a tree a slim chance to survive that's better than no chance.