Any Losses from Heavy Rain?

[Grant Bowie]

Hi all, Sounds like Brisbane has had a bad season for growing this year. Anyone had any losses likely from excessive rain and humidity?

All my trees are fine as the soil drains very efficiently.

Please leave your stories and what you have learned so that others can learn.

Grant Bowie

[tgward]

here in the riverland of sa my dust gauge hasn't turned into a rain gauge yet

[Rory]

My drainage with the mix I use isn’t normally a problem either.
What I did have deaths from was that I heavily cut back on many of them. Now, it takes about 2-4 weeks for the new shoots to finally appear, and when some of them finally had new growth, there was no sun for almost 2 months. This was enough to kill a few of my banksia, being Paludosa and ericifolia ‘little eric’.

It also seriously weakened a lot of Mels, my Euc nicholis, a Kunzea and some others. I now also noticed that I think it’s called the 3 Callathamnus that I was growing. No sun, or basically almost none of it is what has killed the majority of them. Also, for those on the mid to east coast, we have to contend with Myrtle Rust when there is no sun and constant rain. It doesn’t add up to a very pleasant experience.

Interestingly, with Banksia marginata in particular I have noticed that when the new growth appears, it needs sun within about 4 weeks otherwise it can easily die off with the new growth.
And it’s not just a trait of B marginata that has this happen. There are many varieties that I grow that also will die-off with new growth if it doesn’t get sun sometime soonish after appearing.
And if you’ve just heavily cutback the tree, then it is even worse for the tree if all the new growth deteriorates.

The other marginatas that I didn’t cut back prior to the long period of rain and no sun, are doing okay, a little sickly, but have come good now that the sun is back.

On an observational note, the varieties that experienced absolutely no problems at all during the long period of torrential rain, absence of sun and Myrtle Rust were:
Casuarina, Breynia, Phebalium.Thryptomene and Baeckea.

[dansai]

I also lost a young Banksia ericifolia.

I use a locally made potting mix that is bark based and very gritty for all my growing on trees. Every thing other than the Banksia has held up fine. I have a few red pines that didn't seem to like being too wet when I first got them so I placed them so they didn't get much from the automatic system and monitored them more closely than my blacks. They are in a slightly heavier mix than I use, and it looks a little old so will definitely come out of that in winter/spring. They have however not been at all fussed by the rain.

Some JBP that I decandled in summer have been very slow to mature the new growth, which is very short with tiny needles. I think this more a sun issue, or lack there of.

All my natives have been totally loving the rain and not minding the lack of sun. Although we just had 3 days of full sun in a row, and are expecting at least one more (which is more than we have had all year so far - or so it seems), so see if they grow any faster now.

[Redsonic]

I lost a number of Callitris seedlings to damping off. I had them under the patio, and didn't realise quite how much rain was getting to them.
I also lost one small Casuarina that I had chopped heavily before the rain. Rest of my plants sailed through, and my vege garden was very happy.

[Grant Bowie]

Yes, It’s been a year of mixed blessings.

The growth on the pines was so minimal I didn’t decandle this year and will trim back this spring/early summer.

Minimal sun has meant less colouring on some trees(Golden cedar is green) but growth has been patchy. European beech were a bit weak this year but everything else has done OK.

Grant

[Phil Rabl]

I have developed the view that (as a general rule) it is difficult to kill a bonsai by over watering because: (1) the potting mix can only hold a certain amount of water against gravity and if you use a free draining mix there should always be sufficient air in the soil even when it is holding water at pot capacity; and (2) if the tree is getting to the stage of being pot bound, it can be difficult to keep the potting mix / root ball wet.

Obviously, some species may need a freer draining mix than others.

Does this make sense?

[Grant Bowie]

Sure does Phil, But not everyone uses free draining mixes and so this may be a lesson for them, the hard way.

Grant

[Rory]

I have developed the view that (as a general rule) it is difficult to kill a bonsai by over watering because: (1) the potting mix can only hold a certain amount of water against gravity and if you use a free draining mix there should always be sufficient air in the soil even when it is holding water at pot capacity; and (2) if the tree is getting to the stage of being pot bound, it can be difficult to keep the potting mix / root ball wet.

Obviously, some species may need a freer draining mix than others.

Does this make sense?

Its not the draining mix.

Its the lack of sun, and unforunate timing of cutting back hard prior to the long period of cloud and rain. And together with myrtle rust that is the big killer. A lot of varieties need sun once their new growth comes out, otherwise it dies off after a long period of no-sun. Nothing to do with the draining mix.
From my experience, when all the new growth on certain Banksia dies off, its 50/50 whether the tree will have the energy to produce another flush.
Or you can suffer severe die-back, as is often the case with marginata and others.

[isitangus3]

I’m in Sydney and whilst none of my bonsai have suffered thankfully, have lost quite a lot of garden plants due to the rain and humidity.

I think they key difference is my bonsai are on on hard surfaces with good drainage and airflow underneath.


Sent from my iPhone using Tapatalk

[legoman_iac]

No losses here yet, though the rains broke my daily ritual of getting out to my trees, enjoying a coffee with them. Some of the smaller ones have been drying out more than I'd usually let them.

[melbrackstone]

The only thing I lost was a lovely casy in a small pot that was in a rain shadow. I didn't water much, obviously, and this particular tree missed out on both rain and watering for a week, so it turned up its toes. I have put it in a tray in the hope it'll recover, but after three weeks it's just looking deader.

[John(JP)]

With the exception of a Glenda Quirk Juniper Feomina(I think) that I obtained from Phil Rabl that's been a bit antsy of late less than normal growth is all I have noticed and I would think a lack of normal warmth is more to blame and all of mine are in good draining medium

John(JP)
CBS

[Phil Rabl]

I have already posted a comment that a lot of water is unlikely to cause a tree to die if you have a sufficiently free-draining potting mix.

Now I'd like to suggest that a lot of cloud cover is unlikely to cause a tree to die: trees will still photosynthesise on overcast days. Photosynthesis is driven by three key factors: 1. CO2 concentration; 2. light intensity; and 3. temperature.

CO2 concentration CO2 concntrations in the atmosphere are for most practical purposes unchanging (unless you want to focus on the increase due to climate change, i which case photosynthesis is aided by the increased CO2).

Light intensity Zero light equals zero photosynthesis. But the rate of photosynthesis increases rapidly as light intensity increases, and then it plateaus out. This is why trees under shade cloth get plenty of light for photosynthesis. Cloud cover certainly reduces the light intensity, but not to the level where trees will die.

Temperature As with light intensity, the rate of photosynthesis increases fairly quickly as temperature rises, but it drops off as if the temperature increases beyond a critical level. And if the temperature is very hot, the rate of photosynthesis can drop back to zero. So, the cloud cover may be a positive from the temperature perspective is if stops pots from heating in direct sun.

The above information is drawn partly from the BBC Bitesize website which can be accessed at: http://www.bbc.co.uk/schools/gcsebitesi ... nts2.shtml.