I had a friend who wanted to grow them. I came across a garden book that said that the trees will survive here in the north, but the summer is too short for the fruit to ripen. After she read that, she decided not to bother trying to plant any. You are a little farther south, so maybe you might more successful there. Northwoodswis

I found a company called Miller Nurseries who is selling a pawpaw they claim to be hardy to -20 (zone 4). That should be good for you. Good luck. Also, I know this is a little off topic, but I've heard that zebra swallowtails lay their eggs on this plant. Maybe you'll see some caterpillars!

A solid Zone 5 climate shouldn't be an issue. A Zone 4 will be iffy. Genetics and provenance of the plant would probably make a big difference in marginal areas.

-20 isn't zone 4, I wouldn't go by what nursery catalogs are saying. They tend to stretch things obviously for saleability.
I have a pawpaw that's been here for awhile and its taken temps down to -26F. I haven't heard if pawpaw is able to take temps down in the -30s though. Maybe somebody on here has been trying.

Paw paws have been fruiting in Madison, WI that last 2 years i've been down there... The trees are pretty big.

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Both were named varities. I think one was "sunflower" ...i'd have to dig through my pics to find out exactly.

We have 15 acres of wild Paw Paws in Kansas on the zone 5-6 border. Our best producers have been trees grown from choice seed - low seed count and heavy weighted fruit. My family has Illinois farms and Paw Paws grow just as well there. I would agree that zone 4 would be iffy at best. I bought a huge bag of seeds from Lawyer Nursery years ago just for fun and the trees grew very much like our native stand. It might be a inexpensive way to go for testing the zone 4 possibility. Make sure to hang a dead fish somewhere to make sure your flowers get pollinated (they're fly - not bee pollinated). In my blog archives (Sept 2009) there's several mentions of paw paws and a few links to news articles/videos etc - Rick Godsil, Wagon Wheel Orchard

Here is a link that might be useful: Wagon Wheel Orchard paw paw article

Wow Franktank, that's a beautiful little pawpaw tree, thanks for posting that picture.

NYgardener, it sounds like others have given you some great advice on trying pawpaw...

Rather than add my guess as to success in zone 4, I'll put it more technically:

Pawpaws require a frost free growing season of around 160 days and at least 2600 GDD (growing degree days) to ripen. If you've got this, I don't think you're exact zone really matters all that much (few true zone 4 climates would meet this criteria I think, and the newest zone maps show very little zone 4 climates left in the continental US).

Hope this helps...
Oh, I found this info at: http://www.hort.purdue.edu/ext/ho-220.pdf

Thanks for the good advice, all! I think I'll try a few seedlings as well as named strains in both locations and see how they perform.

KansasApple-

Good advice regarding the dead fish! I have several of these paw paw trees and had difficulty in getting them pollinated until I hung some chicken around one tree. Do you hang decaying matter on each tree? My trees are exaclly very close together.

Michigan State University did trials here and found that NC-1 and Davis produced the best fruit there. Michigan State is in Lansing Michigan which is a little north of me. We are in the middle of zone 5.
NC-1 was developed in Ontario. I think that is your best bet.

Pawpaws are native up through Ontario. Give them a try. And yes, I tie road kill in the trees.

Good to know. I think I'll look for varieties that are known to do well in cold areas, so that the trees aren't damaged by the occasional harsh winter.

I don't believe any of the varieties will be damaged by your colder weather. The only problem with colder zones is ripening time. In other words late ripening varieties might never ripen in a shorter season.
Like I said, NC-1 and I think Davis were both developed in Ontario

I know someone in WI zone 4 who is growing and fruiting PA Golden paw paw. Hope thats helpful.

Thanks! I'll look for those -- I'll need to plant a few different varieties for pollination, from what I understand. They'll be planted near a cattle farm, so hopefully there will be enough flies about.

There was a study done in 1999 in upstate NY in an area that was zone 5b.

http://www.pawpaw.kysu.edu/PDF/merwin03.pdf

NC-1 and Taytwo did well and are fairly easy to find. Of note, they did not have any Peterson Pawpaws tested, I think because they were not available then.

Ordered an NC-1 and Allegheny (Peterson) for the spring of 2014, wish me luck! Zone 5a here.

OIKOS Tree Crops claim their pawpaws are hardy down to -30F: http://www.oikostreecrops.com/Pawpaw--ECOS/p--305/

My Sunflower pawpaw bit the dust after two years of good growth just south of the Twin Cities, MN. It appears the bark took so much of a freeze-thaw beating that it killed the poor thing. I think the coldest it saw was a night or two of -25F?

When I try pawpaws again, I think I'll go with OIKOS simply for the fact that they're seed-grown; if they ever get frozen back at least I don't have to worry about a bud union.

Oikos is notorious for sending out extremely small plants. FYI

The trees at the garden in Madison, WI aren't Sunflower, they're not commonly available varieties. I want to say one is Watson, something that begins with a W, anyway.

I have PC Golden and NC-1, but they're young and haven't fruited. In fact, they're still short enough to be covered by snow during that cold snap last week.

A relative in northern WI, zone 4, remembers eating wild pawpaw from the woods around his house about 70 years ago. He said they were tiny, the size of your little finger.

If you try some grafted, known early-ripening varieties, it's worth a shot.

fruitmaven - Peterson had a cultivar called "wabash." There is also an Indiana cultivar called "wilson."

Wilson, that is the name of one of them, at least. I'll look at the tag for the other when I go there again. (The garden has a tropical conservatory as well, so it is a nice winter destination.)

Of the Peterson Pawpaws, Allegheny appears to be the best bet if you are in a zone 4 or 5. The fruit is smaller and seedier than his other varieties, though still much better than wild ones. The smaller fruit ripens faster, so you are much more likely to get a harvest before winter sets in. Keep in mind, I will be getting my first Pawpaws this spring (2014) so I am not speaking from direct experience, just what I have been able to find with persistent searching on the internet.

Pawpaws are extremely tough to get established as new young plants, let alone in a z4 location where the ground freezes deeply. Pawpaws and any borderline plants takes at least 3 full growing seasons to get established. The roots have to be able to get deep, and the top wood must develop sufficient girth to become fully hardy. While not in z4, Colorado is a tough climate to get them to take because of our dry air, high altitude extreme sun, and nearly daily freeze thaw cycles in winter. In the process of losing many plants (pawpaws and others) and experimenting, I have learned a few ways to get them through the first 2-3 years which is when failure is most likely. I have established and grow several plants which are not considered hardy in my climate such as southern magnolia, figs, hardy palm and others. Setting young plants out in the spring after frost, use a wall-o-water around the plant, and locate plants on an east exposure next to a house. Use bamboo sticks to hold the wall -o-water as open as possible when the weather gets hot, and keep it well watered. Leave the wall-o-water on all year, and remove all but one of the bamboo poles in the fall. Bury the whole works in dry leaves at least 6"+ thick, and 3 feet wide after the little plant drops its leaves. To keep the leaves in place use burlap or similar material to cover the mounded leaf pile. Plastic may be okay in wet climates. In spring, gradually remove the cover and leaves, but keep the wall of water in place to protect the plant from late freezes. In summer, the plant may outgrow the top of the wall of water, and may be removed. In fall replace the wall-o-water and repeat the process from the year before. The next spring after danger of frost remove the wall-o-water. In fall just mulch deeply in leaves. Seedling plants of early ripening cultivars on own roots in pots seem to be the hardiest. Use foam pipe insulation tubes to wrap as much trunk as possible each fall, and deep mulch. Remove in spring. I hope this is helpful. Once well established, they should be able to take severe winter cold that wipes out young plants. It seems to me that it may be possible to grow pawpaws in those z4 locations that have sufficient summer warmth.

The two pawpaws growing and fruiting in Madison, WI (zone 5a) are Wilson and an unnamed seedling.

Ivywild142,

Great advice! Just wondering what palm and what figs you have managed to grow with this method.

Responding to a prior inquiry, I have a sabal palm called McCurtain, and Chicago hardy fig.
The method above has worked for me to establish many plants rated 1-2 zones warmer. The winter 2013-14 will be a real test winter for the Midwest. Pawpaws that are well established will probably make it. Those newly planted, or a few years old, may not survive in more northerly locations. Perhaps those buried in deep snow will be okay. Even well protected marginal plants may fail to survive in such severe conditions. It will be interesting to find out what survives and what fails come spring.

There are native pawpaws in NY. Pretty cool huh? A tropical that got stranded when the glaciers moved south and survived to the point where now it won't grow in my area.

Here is a link that might be useful: PawPaws (Cornell Univ.)

One more comment regarding a pollinator insect. Try growing voodoo lilies around your trees. Voodoo lilies are perfectly hardy and smell like a rotting carcass. I assure you there will be plenty of pollinators around your paw paw trees!

If Apple trees survive, probably even Asimina survives too

I don't know how these ones compare to where you are, but there's also these: https://www.greenbarnnursery.ca/products/paw-paw-taylor