Is pawpaw dormancy for winter based on light or soil temperature? My triloba lost all its leaves in November and didn’t bud break till March. It was so early I thought it died or the leaves got burnt off, because it is still firmly 70s here in November.
In contrast, my slim leaf pawpaw didn’t leaf drop till January when we had temps below 40. At any rate, it looks really healthy now, and I’m really happy with it.
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I’ve noticed mine tend to turn on and off when my 6” soil temp gets around 55°F.
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I would imagine it’s length of day, when the days shorten they know. I say that because my peaches go dormant around that time and we don’t have a frost until usually January. I didn’t plant my pawpaws until March but they immediately broke bud, I’ll let you know when they drop leaves
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I think typically dormancy in trees that go dormant is mostly triggered by soil temperature, but there are some with a photoperiod trigger. It wouldn’t matter when your first frost is, since dormancy is probably triggered by soil temperatures much warmer than that.
It should be relatively easy to test, stick a waterproof 24/7 grow light above one pawpaw (high enough to not heat the soil much), and see if that one fails to go dormant when the others do. I suspect soil temperature is a much bigger role than photoperiod, but don’t know for sure.
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Well the reason why I asked is that November is way before our soil temperature has dropped to below even 65. Air temperatures are still 70s unless its a cold front, and even if a cold front comes through, the ground is exposed to relentless sun since fronts push all the clouds away. And the fact that leafdrop was in November and bud break was in March, which are similar light exposure times.
Basically I was asking if I should be expecting to go dormant in November, like it did last time, consistently, or if this year was just a fluke due to being the transplanting year. Nothing else I had went dormant nearly as early, and it was later then most on leafing out as well.
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The reason why I said light length or angle of the sun is like what @sharq said. Soil temps here are well above 60 deep into December. Plenty of 70 degree days most decembers. But then again I haven’t measured it.
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I went down a rabbit hole on Google Scholar, and as far as I can tell no one has systematically attempted to discern what triggers dormancy in pawpaw. I did find this interesting (unrelated) summary of a test grove that confirms that Susquehanna seems prone to random death, they only had 13% survival, the worst of 28 tested varieties/selections:
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Ahhh the famous “RVT” Regional Variety Trials.
Those guys and gals are among the experts 
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I would also imagine pawpaws will struggle in general for you in the pnw, due to lack of heat units.
I think they grow less per year due to the short growing season, but there are some mature, healthy pawpaws around Seattle. In warm spots, though. Mine are in a cold spot in my yard, since I gave the warm spots to other things.
Here’s a thread with some photos of local trees:
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My pawpaws grow about 1-2 feet each year. Maybe not the fastest but still not shabby. They accelerate as they get older.
They definitely want warm weather which is in short supply in the PNW.
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That is a fact. The first couple years in the ground you don’t get much at all. At about four foot the growth really starts to increase each year.
pawpaw peduncle borer
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Only 54% survivability overall after 7 years and change is disappointing although that Susq number certainly weighs it down. Hopefully on of my Susq seedlings survive, but those 3 are low vigor. My overleese in the field (OGW tree) has been pathetic from day 1 and only puts on 1-2”/yr with a lot of bark splitting and cankering (not SW injury) so it’s interesting to me to see they struggled with that one as well.
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Correction - these aren’t the RVT results as that was done across varied locations (hence “regional”)
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I’m reduced to 3 trees now, the Wabash was the smallest and a squirrel uprooted it. the others are fully leafed out now, I’m feeding fish fertilizer every other week for now plus urea/N from household sources, and will see how they go.
bummer to lose one I grew from seed though
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The fact that they only had a single Susquehanna survive out of 8 trees is definitely not encouraging. Even removing those 8 trees from the calculation, though, they did seem to lose a lot of trees. It would be interesting to see the breakdown of which ones died from drought, disease, or just failed to wake in spring (like Susquehanna seems to do).
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Thank you!
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Susquehanna is supposed to be vigorous and fast growing. My Susquehanna seedlings definitely have that trait compared with other pawpaws.
Mine certainly was until this year when it died back to just above the graft. It was easily twice the size of my next-largest pawpaw (Shenandoah), purchased at the same time as 1 gal from Raintree.
I wonder if those traits are related, where it grows so vigorously because it’s not storing away as much energy for winter, and is instead using the energy for growth. Then, after a long winter it sometimes self-prunes most of the trunk if it lacks sufficient stored carbohydrates to support new growth on all the branches that have been dormant.
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