White pine seasonal needle loss

I have a JWP that I have been taking care of for about 5 years

. In the fall some of the needles, usually only on sections of the tree, get yellow and then over the winter drop off completely. In the spring needles grow out of the bare branches and seem to do well all season until the next fall, when it happens again. The tree seem to be getting weaker with time, however. I sent needles to the state department of agriculture. They said no pathogens present. The tree pictured was repotted in 5mm Aoki blend conifer mix last year and the roots seemed healthy. It gets lots of sun. My water pH is 7-8. Any advice is appreciated.


My White Pines do lose needles in autumn, but that is a lot. I notice that you have it in a room of some description. Mine are outside all winter, although I keep the rain off them.

@Joe55 , you give no indication of where you are , or how you summer / winter the tree. Looks like a winter cold room above. Do i see other healthy pines behind the Jwp? Organic fertilizer?
JUST FYI…Pines need some time out in the cold to rest during winter… several days close / below zero F.
Without, they tend to slowly decline and die… mine do OK at <20F for several weeks in a protected shelter. Only covered below 25F. Dicideous trees get mulched below 35, covered below 20F.
Might be as simple as a repot in spring, remember to only do about 1/3 of roots at a time… Watch Mirai videos. See the Mirai forum winter blogs.
Summers they get mostly full sun… unless the temp gets above 90F, then more water and shade to survive. Shallow roots in pots fry easily. I lost my Jwp to this.
January, 15 F, cold here. Do not move a warm tree straight to freezing. Needs to slowly transition. Week or two… protect it from wind
I dought it is a deciduous J W pine…:roll_eyes:
Good luck.

Thanks for commenting. I live in central PA. Up until this year I had kept all of my bonsai outside in a protected corner against the house, on the ground in a wood and plastic cold frame with a retractable roof. We get more cold rain than snow, and only rarely get temps below 15 degrees. But whenever possible I let the snow cover them. They get full sun over the summer, although I move them into partial shade when it gets hot. I repotted the tree in question this past spring, so thought some winter protection might be needed this year.

This winter the trees are in a shed with LED grow lights (Lux equal to a cloudy day) and a heater to keep the trees just above 34 degrees, assuming that the cold wet winters were the cause of the decline. The other JBP in the background of the photo is healthy, although I have a third JWP that has the same complete regional needle loss problem. My JBP are all healthy, cared for in the same way.

BTW, I re-measured my water pH with an actual meter instead of a dipstick, and it is actually 6.7, if that means anything.

So I can’t get zero temps, but will allow the pines to slowly acclimate and freeze. Thanks again for your suggestions.


Sounds like you know what you are doing… your pH is great… good for bonsai.
Not much different than I do/have done. Are you using organic fertilizer? I use organic (Dr Earth with fungal myccelium, or Biogold…Ryan suggested it.), and supplement with some good quality inorganic. I really like seaweed emulsion.
Several of the JWPs in local club here have had limb loss in recent years. Mine just lost health in the fall, was repotted in spring (almost no rootwork), buds were good, and was dead by the mid summer. Nothing out of regular…I assumed it got too hot the previous summer. It may have been an infection, fungal?
Made me very sad. Was happy and healthy for 20 years…

Two comments Ryan made recently that have stuck with me that may or may not apply to your Japanese white pine. They are: people often over water their JWPs and if there is a problem in the foliage throughout the tree, there is probably a problem in the roots.

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Here is what happens in the spring. Wierd, right?

As long there is green, you are still in the game. BUT with that foliage loss you have to be super careful with watering if the tree makes it til spring. If it rains a lot, protect the tree under a carport. You know - balance of water and oxygen. Consider a heat pad to stimulate root growth. Avoid stressing tree in windy, hot conditions. Watch the colour of the shoots. Green is ok. Browning is dangerous and some afternoon shade may be called for. Light organic fertilizer if any at all. Misting the foliage and not the soil could help.

There is still the cause of this in the first place. l would avoid messing with the roots when it is so weak. But that could be where the problem lies. If things deteriorate further, what do you have to loose by checking the roots?

I was ready to ask the same thing for the next Q&A Live 6. My White pine seems to be turning yellow more so at the end of the needles. I can’t say I’ve lost any. I live in Northern VA and it’s been pretty cold lately (20’s to a

single digit). I have two other types of pines and they seem to be holding their green color just fine which is why I’m concerned. Any help would be appreciated. Victor

that seems to be too much water… be sure that the tree needs water before watering again.
JWP don’t like water!

It’s all been snow and rain.

Today I noticed a number of my strobus needles in Toronto are off color. Partly due to the dulling a lot of conifers in the winter do. Some is a waxing foliage protection, some could be too much water if the roots stay wet in conditions above freezing and some could be needles drying with less water flow in very cold conditions. The container growing restricts the roots from the soil mass below and thus more subject to temperature changes for the worst results. Strobus needles are very fine and fragile. Winter is tough on our bonsai. Putting the trees in a cold frame out of the wind and mulching the pots may not be enough. Perhaps digging them into the earth is necessary. One grower takes his trees out of the pot and heals the root ball in the ground. That is a lot of work.

Has anyone figured this out?
I’m having similar issues with my JWP this year, last year it grew superbly, come spring it started yellowing at the tips now as candles are growing, it started dropping needles.
My best guess is root issues.