Silver Birch dying from seaweed fertiliser?

Chad Smith

Hi,

we have a healthy (or HAD a healthy) 2.5-3m Silver birch in a new oak 1/2 wine barrel (tub 150L capacity) in front of our south-facing house, about 500m from the seaside south of Adelaide. It was growing well and looked normal, with a little yellowing.

The 3 year old birch had been in this tub for about 5 months, planted during winter, and I thought the slight yellowing of older leaves was due to the soil running out of goodies, so I applied a dose of Maxicrop seaweed fertiliser at the recommended rate for fruit trees, 50ml/9L. I applied it to the soil on an overcast, 22 degree, not very windy day, late afternoon.

Two days after the application, the oldest leaves started to turn brown very quickly. I tried to 'flush' the soil by doubling the watering when the browning began, but nothing slowed the browning. Four days after, almost all leaves had turned brown but a flush of new green shoots had continued along the branches. Six days after application, the new shoots have now also turned brown and it looks like, the tree might be on the way out. The browning does not look like a fertiliser 'burn'.

Could you please tell me is there a way to possible save this previously healthy silver birch? The tree is sentimental, and was only in a tub as we are waiting to decide on a new property where we would have planted it. I chose seaweed fertiliser specifically for this tree because I thought it would be more gentle on a birch in Adelaide's harsh climate! I bought the birch for my wife when she relocated from Finland, a bit of a reminder of home.

Also, if not, was it the seaweed fertiliser that did it? I have actually never used seaweed fertiliser before, but used this same bottle on other parts of the garden on the same day without any 'burn' or devastating results. I usually apply pelletised organics like neutrog, and periodic aquasol at lower rates to all plants. There are 3 young flowering plants in the same tub... and they are fine.

Thanks for any input! I hope it pulls through!

chad

FYI Maxicrop has:
Nitrogen as urea 4.6%
Phosphorous 1.2%
Potassium 3.1%
Sulphur .06%
Iron .05%... plus trace elements.

Eric Frei

I doubt very much it was the seaweed fert.

When the first browning occured that was a bad, but the second flush of growth all over the place is often what I call the final flush.

As the tree loses photsynthesic capacity it fires life into dormant buds along stems hoping that enough leaf is grown to make sugars ... but sometimes the tree expends all it's stored energy in doing such and cannot sustain the foliage grown due to the fact that too many roots have died already.

You'll also see the same phenomena after fires with eucs, or like we had here extremely strong winds that rip all the leaves off trees. Difference is with the winds and fire is the root system is still OK and the tree can "kick start" itself.

This picture shows what the trees looked like 6months after the storm with all the growth along limbs and even up trunks.



And a close look, see how the "fluff" is growing.



There could be many factors at play with your tree, it could be drowning in water, the soil could be hydrophobic or out of pH range, could be saline too. The problem was pre-existing and without thorough checks who knows what really happened, but I really doubt the seaweed stuff hurt it, unless of course you mixed it all up in the watering can that did the weed and feed on the lawn etc.

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Chad Smith

Thanks Ekka... it is still strange to me as there has never been a sign that the tree was unwell, as the first symptoms appeared two days after the seaweed... I made the obvious connection although I did think it was unusual.

(BTW definitely no poisons used in that watering can! and some of the same batch went on other plants)

Is there anything I might be able to do to help it survive? Get it out of the pot ASAP into new soil? Get the soil tested? As the branches are now the source of energy I suppose any pruning is a bad idea?

There is very good drainage in the tub and no signs of sub-surface problems like bugs, root rot, etc. It also holds the moisture quite well without being waterlogged.

Thanks,

chad

Eric Frei

Yep, I'd lie it down and carefully pull it out of the barrel, see what's going on.

Also, smell the soil, sweet is good and if it stinks that is bad.

Try grow something that grows fast in that soil ... wheat seeds etc.

Take some pics too, lets see them.

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kieren

I've seen a lot of silver birch in poor health and not long for this world. I don't think they can handle the adelaide environment the UV index has gone through the roof this year meaning every thing that cant take the extreme weather is in decline sad truth is they will most likely die and along with most exotics.

but as well as that i have noticed that the (N)nitrogen, (p)phosphorus (K)potassium analysis of seaweed ferts are not well balanced and appears to be mostly made for australian natives. I'm not saying this is the cause of the decline of the birch just noting my observations