Purple/Reddish needles on Japanese Black Pines

[Stimpy]

Hi everybody,

I am pretty new to Bonsai and i have these JBP seedlings that i have for about 3-5 months, some of the needles are starting to become a little purple/red on some of the needles.
Not really sure what could be the cause of this, could this be a watering issue? They get about 6-8 hours of direct sunlight when the weather allows it. Do they recover from this?
Any help/feedback is greatly appreciated.

Thanks in advance!

Sam.L

 

[Paradox]

Could be, yes.
Looks like the soil is heavy and could be staying wet.

 

[Wires_Guy_wires]

Cold can help too in turning them purple. Combined with a little too much water they will probably continue to change color. They should go back green again in spring.

 

[Stimpy]

Could be, yes.
Looks like the soil is heavy and could be staying wet.

Yes i assume the soil is pretty dense, i was planning on repotting them with a better more aerated soil mix. But since autumn just started it might be better to wait for spring again.
Or do you think it's fine to repot them now aswell? I read it's better to wait until spring.

 

[Stimpy]

Cold can help too in turning them purple. Combined with a little too much water they will probably continue to change color. They should go back green again in spring.

I assume i should hold back on the watering then . Good to hear that they aren't doomed for now, hopefully they will do well during the winter.
Thanks for replying both of you, really appreciated!

 

[Wulfskaar]

Yes i assume the soil is pretty dense, i was planning on repotting them with a better more aerated soil mix. But since autumn just started it might be better to wait for spring again.
Or do you think it's fine to repot them now aswell? I read it's better to wait until spring.

I think they are fine either way. You can repot JBP in fall or spring. I think they will be fine in that soil until spring though. Just don't over water. They don't mind being on the dry side (not totally dried out).

I agree with Wires_guy_wires... the purple needles are normal in winter for these young JBP. They will be fine.

 

[NeedlesAndLeaves]

I had the same on a collected (Scots Pine) seedling. To much water, colder temperatures and a bit of stress probably. I made sure it stayed not to wet anymore. The needles turnt back to green next spring as if nothing happened. Pics are two years apart with the purple needles on the first one.

 

[damiano68]

E' semplicemente una questione di freddo, l'assenza di legno impedisce un flusso perfetto e gli zuccheri si ossidano.
In primavera torneranno verdi

 

[Paradox]

Yes i assume the soil is pretty dense, i was planning on repotting them with a better more aerated soil mix. But since autumn just started it might be better to wait for spring again.
Or do you think it's fine to repot them now aswell? I read it's better to wait until spring.

I would wait until spring and be careful about watering. Water when they need it, ( soil almost dry) not on a set schedule.
To tell when, get a wooden chopstick and stick it in the pot and leave it there. Take it out once a day and look at it and water water when it is almost dry.

 

[Shibui]

Have these seedlings been fertilised? Purple/red foliage can also be a symptom of potash deficiency.

 

[Stimpy]

I would wait until spring and be careful about watering. Water when they need it, ( soil almost dry) not on a set schedule.
To tell when, get a wooden chopstick and stick it in the pot and leave it there. Take it out once a day and look at it and water water when it is almost dry.

Awesome, great tip. Thanks for your help!

 

[Stimpy]

Have these seedlings been fertilised? Purple/red foliage can also be a symptom of potash deficiency.

No i haven't fertilized them yet since they sprouted, do you recommend giving them some fertilizer? I guess it won't do much good since winter is approaching

 

[Shibui]

Winter is probably a little warmer here but we've found that JBP are not fully dormant in our winters. Occasional winter fertilising gives much stronger spring growth so appears to be effective. JBP are very winter hardy and trees here have never responded to fertiliser with sudden, out of season growth so no risk of winter damage.
Seedlings are very responsive so I'd certainly be giving at least 1 application of soluble fertiliser immediately. The worst you can get is no response and wasted fertiliser but I suspect you'll see a very quick improvement in colour before the cold.

Seedlings grow fast so they do need nutrients to fuel that growth. The peat based seed mix has virtually no available nutrients so your pines have been relying on the nutrients from their seeds and whatever they can pick up from your water. 3-5 months is a long time on bread and water. I suspect you would have seen much better growth with better soil mix and regular fertiliser. Some things to consider for next year - and your next seed growing attempt.

 

[Stimpy]

Winter is probably a little warmer here but we've found that JBP are not fully dormant in our winters. Occasional winter fertilising gives much stronger spring growth so appears to be effective. JBP are very winter hardy and trees here have never responded to fertiliser with sudden, out of season growth so no risk of winter damage.
Seedlings are very responsive so I'd certainly be giving at least 1 application of soluble fertiliser immediately. The worst you can get is no response and wasted fertiliser but I suspect you'll see a very quick improvement in colour before the cold.

Seedlings grow fast so they do need nutrients to fuel that growth. The peat based seed mix has virtually no available nutrients so your pines have been relying on the nutrients from their seeds and whatever they can pick up from your water. 3-5 months is a long time on bread and water. I suspect you would have seen much better growth with better soil mix and regular fertiliser. Some things to consider for next year - and your next seed growing attempt.

Alright i see, very informative! I've ordered some liquid fertilizer and will add it with the next watering session. Many thanks for taking the time to reply!