JWP yellowing

[Rgw66]

JWP starting to look a tiny bit sad. It's not bad at all but I want to make sure I am making changes to appropriately address the tree's health.

Older growth is getting some general yellowing across the whole tree and some browning on the tips here and there. This year's growth still is looking mostly green/healthy except maybe 1-2 branch tips.

We had 2ish weeks of strong thunderstorms every day and I was worried it was getting overwatered, but the tree looked very string and healthy. It has since been raining a lot less for the past 2 weeks and we are now watering it every 1-2 days.

I am torn on if it is yellowing because it was getting over watered a few weeks ago, or if it is because it is now getting under watered.

The weather was also a lot cooler when it was raining every day. It has since been consistently in the 90°s and very humid. So wondering if it also could just be from the heat.

Soil is 2:2:1 mix of lava rock, pumice, and akadama, so I imagine it would be hard to over water, but I know JWPs are sensitive to overwatering so I am trying to be mindful of that.

 

[Wires_Guy_wires]

When in the year do your pines lose their needles from the last year?

 

[Rgw66]

When in the year do your pines lose their needles from the last year?

Only got the tree in October, so I do not know. Is this a typical time for it to lose last year's growth?

 

[Nybonsai12]

Japanese white pine typically drop old needles in the fall. They will yellow and then fall off. Has the tree been heat stressed? I've had one of mine drop needles very very early that i suspect was due to heat stress but have no way of knowing. Tree never skipped a beat with new growth though.

 

[Wires_Guy_wires]

Only got the tree in October, so I do not know. Is this a typical time for it to lose last year's growth?

No it's not, usually it should be around the end of september, october to early november. But if you haven't seen it before, this one might be early. Add a little stress on top of that and it might be extra early.
The yellowing seems to be compartimentalized to only the old stuff from what I can tell, which is good news.

A week of rain should not be an issue. A day of drought can be problematic depending on the temperature. Best you can do now is to keep the conditions stable, don't worry about the rain and it getting wet - temperatures drop together with rain and plants know how to handle that. High heat and dry conditions can be more problematic, but with our watering schedules it's usually easy to prevent large amounts of damage.
I'd keep an eye out, see if it progresses into the new foliage. If that is the case, there's reason to worry. But then again, it's a pine, there's not much you can do at that point. One of my oldest JRP was cooked this year and it was horrible to watch the decline, but yeah.. I couldn't do anything but watch my watering and hope that it wasn't too late, but it was.

 

[Rgw66]

Japanese white pine typically drop old needles in the fall. They will yellow and then fall off. Has the tree been heat stressed? I've had one of mine drop needles very very early that i suspect was due to heat stress but have no way of knowing. Tree never skipped a beat with new growth though.

Definitely could be heat stress. We have had a handful of very hot days here and it has consistently been in the mid to high 90°s a lot of days.

 

[Rgw66]

No it's not, usually it should be around the end of september, october to early november. But if you haven't seen it before, this one might be early. Add a little stress on top of that and it might be extra early.
The yellowing seems to be compartimentalized to only the old stuff from what I can tell, which is good news.

A week of rain should not be an issue. A day of drought can be problematic depending on the temperature. Best you can do now is to keep the conditions stable, don't worry about the rain and it getting wet - temperatures drop together with rain and plants know how to handle that. High heat and dry conditions can be more problematic, but with our watering schedules it's usually easy to prevent large amounts of damage.
I'd keep an eye out, see if it progresses into the new foliage. If that is the case, there's reason to worry. But then again, it's a pine, there's not much you can do at that point. One of my oldest JRP was cooked this year and it was horrible to watch the decline, but yeah.. I couldn't do anything but watch my watering and hope that it wasn't too late, but it was.

Thanks for the thorough response. So it seems like you think it may be a heat issue vs a over or under watering issue? Is there any other ways to help mitigate that? And what steps, if any, should I take if I start to see the yellowing spread/get worse?

 

[Shibui]

It appears the yellowing is confined to the older needles. New needles at the tips of the shoots look healthy and good colour. I'd certainly be checking soil moisture more closely but, given only older needles are affected at this stage, I'd be siding with @Wires_Guy_wires - natural shedding of old foliage.

Yellowing can also indicate nutrient deficiency. What's your current fertiliser program?

 

[Brian Van Fleet]

This year’s growth looks fine, last year’s needles are looking tired, so if it was mine, I wouldn’t be too concerned. I am watching my JWP closely this year as I think the roots got too hot last summer and it resulted in some burning of needles; which looks similar to yours. I’m keeping it in less sun during the hottest months and it seems to help.

 

[Rgw66]

It appears the yellowing is confined to the older needles. New needles at the tips of the shoots look healthy and good colour. I'd certainly be checking soil moisture more closely but, given only older needles are affected at this stage, I'd be siding with @Wires_Guy_wires - natural shedding of old foliage.

Yellowing can also indicate nutrient deficiency. What's your current fertiliser program?

All great news. Thanks. I will keep a close eye on it and might movie it to a slightly shadier spot as @Brian Van Fleet suggested.

I did a few rounds of fertilizing after it was repotted in the spring, but it has been a while so I will definitely give it some and see if that helps.

 

[rockm]

It has been extremely hot and extremely humid for more than month. Humidity has been historic in the last two months with dew point temps in the mid 70 to even mid 80s in the region. White pine is a cooler climate species -zones 5-7 and doesn’t like a lot of humidity and evening heat. I’d be surprised if there weren’t any heat stress involved.

D.C.’s soupy weather marks one of the most humid summers ever recorded - WTOP News

The D.C. area will get a bit of a break over the next few days from the hot and muggy weather. But this is already one of the most humid summers on record.

wtop.com

 

[emrylle]

This year’s growth looks fine, last year’s needles are looking tired, so if it was mine, I wouldn’t be too concerned. I am watching my JWP closely this year as I think the roots got too hot last summer and it resulted in some burning of needles; which looks similar to yours. I’m keeping it in less sun during the hottest months and it seems to help.

out of curiosity, how long have you had your JWP? I want to buy one, but im afraid that it won't survive in my climate (Dallas - 8B). i keep most of my trees in deep shade in the hot months.

 

[Rgw66]

out of curiosity, how long have you had your JWP? I want to buy one, but im afraid that it won't survive in my climate (Dallas - 8B). i keep most of my trees in deep shade in the hot months.

Haven't even had it a year yet. I do know a few people in the area who have kept white pines for a long time with little issue. I think Dallas might be a little too far south though. They will have a hard time thriving without a a winter season of consistent cold temps.