What is the perennial part of potato onions?

This is my first year getting potato onions to grow.  I can't seem to find how they are perennials.  Most of what I have read, and watched shows removing all the onions, curing them and replanting them.  Maybe I'm wrong, but when I think perennial I think plant once and it continues to grow.  Can you remove all but one onion and leave one to reproduce?  I don't mind replanting them, I just don't understand how that is perennial.  Thanks

Kim said Potato onions are a type of multiplier onion that makes multiple bulbs, rarely sets seed, and is not a topsetting onion like a walking onion

https://permies.com/t/138977/perennial-vegetables/Potato-onions-easy-grow-perennial

I have not grown this variety as I have the walking kind.  As Kim explained, "they Multiply".  Plant once and you don't have to plant again as long as you leave some in the ground as I do with walking onion.

To me, that is what makes them perennial.

Potato onions and shallots are multipliers, like walking or bunching onions. When you harvest these clumps, you dig them up and put one back to multiply and make another clump for next year. The potato onions and shallots do better with the added step of removing all of them, doing the cure and replanting later. Here in Minnesota we don't replant until spring as they aren't fully winter hardy. Harvesting thins out the patches so that they will be able to keep producing year after year. Potato onions and shallots work well in regular annual garden rotations instead of the perennial beds. I think of them as annual clones. By the way, the shallots we have (probably a potato onion) keep for over a year and a half.

Jen - I'm with you. If I have to pull and cure them all at one time, I don't see the advantage. I had hoped that I would be able to pull them as I needed onions, nope, doesn't work like that. I have the walking kind, not the potato ones, but it seems like the same issue.

I grow shallots and I'm okay with doing this for them, because they are expensive, and that's just how shallots are.

I'm moving to relying on shallots and leeks more, because I really like them better and they are easier for me to grow.

My biggest general onion use is for caramelized onions, often I just buy a really large bag and do a huge batch, like 20 lbs.

I've always thought of them as perpetual, rather than perennial.

I'm so glad you all are giving me great advice.  Sounds like I should remove them cure them and replant.  I live in Northern California zone 9 b.  We have mild winters. We may get slightly below freezing a handful of times.  Last winter if I remember right I think it got down to 30 3 time.  I may leave a couple in just to see what happens.  I only got a small amount of bulbs. The cost isn't to bad, but after shipping, it adds up.  I think this year I will keep most of them to replant.  
Off subject, but it's often in the back of my mind if I can grow things like potato onions, and okinawa spinach, longevity spinach, tree collards comfrey, stuff you just can't find in my area, that someday I can make cuttings and supplement my income so I can work less hours at the job I hate, and have more hours to do what I love.  My sister in law has already started the ball rolling. I try to give her eggs, we have way to many. She has been buying them at a hole foods store for 7.00 a dozen. See gives me 6.00 a dozen, and wants 3 dozen a week (vegetarian) that's 73.00 a month. I spend about 42.00 a month on chicken feed. She spends less, probably getting better, fresher eggs, and we get free eggs, I buy organic food for my girls, and there's money left over.  The only downside is I feel guilty because I give the rest of the family eggs for free.  I have told her this, but she insists.  I have never needed fancy things, new cars, or ton of shoes, you know what I mean, so maybe someday I will make it work.
Thanks everyone.

One of my potato onions is good to seed. Should I let it mature and try to harvest the seeds? Or should I cut it off?

Jen Fulkerson wrote:One of my potato onions is good to seed. Should I let it mature and try to harvest the seeds? Or should I cut it off?

I think many folks cut them off, but you can let them do that! I have. It will make bulbils (baby bulbs) and they can be planted.

After the winter we had this year with temps at -5 degrees for several days, my walking onions did just fine.

I would vote for trying to leave a couple of potato onions to see if they will survive.

I don't know if potato onions are the same as walking onion in the fact that mine only have a two-year lifespan but just keep multiplying.

Minnesota cold doesn't kill walking onions. One year I had harvested all of the top set bulbils to keep them from walking around the garden. I usually give them away to people to start new patches but that year I fed them to our sheep, who loved them. I had a couple of handfuls left sitting in a bucket in an open-sided shed, where I forgot about them. In the spring I discovered the leftovers that were sprouting new growth. It had been down below -20* F that year with no negative impact on their viability. BTW, we were given the walking onions by a friend over 38 years ago.

I like the term perpetual to describe potato onions/shallots. Another advantage to lifting the entire harvest is that at that point you can inspect and select which bulbs you want to replant. Not exactly plant breeding but does help with the selection of genetic material to maintain.

This is my first year growing potato onions, but I do have an accidental perennial garlic patch. Long story about how it got started, but the basic rule is, any bulbs left in the ground will simply keep growing and multiplying on their own, no matter how crowded they get. As long as I harvest from the edges, the patch stays dense enough to smother out any weeds. This means the bulbs themselves are fairly small, but that's offset by the fact that there's no work needed to grow them.

If I want bigger bulbs, I can transplant some to a different patch so the bulbs have room to develop.


I would think potato onions could be grown the same way.

I have a sort of perennial patch of garlic as well.  I've found the bulbs aren't worth harvesting because they end up being so small, though like Ellendra suggested I probably could separate off some and plant them out separate.  I've been replanting separate bulbs from some garlic I got at the farmers market for years now.  It was a variety that seems to form only a few cloves each, but they are big cloves.  Anyway, what I have done with my "perennial" garlic spot is to sometime snip and use the fresh greens.

My thinking is that you might well be able to do this perennial potato onions too.  I do have some onions I've planted in the past than never seem to really produce a good bulb so I leave them and they keep growing back.  I've snipped green onion leaves from them from time to time and more or less harvest them this way.  At the right time I bet you could snip the whole top part off leaving the live roots in the ground which would continue to live and grow on producing a new green onion at some point.  

I started some walking onions last year which didn't seem to do that well so I never harvested anything.  This year they have come back looking much better.  I'm hoping this means they are getting better established and happier.  I too have wondered just what was perennial about them?

"Perennial" alliums are like all perennials that are clump forming in that eventually they will crowd themselves out. Even perennial ornamental plants benefit from occasional dividing, otherwise they succumb to the "donut" effect where the center of the clump dies out and the outermost parts continue on. Perennial shouldn't be taken to mean an entirely hands-off planting. You'll get more out of it with a little bit of effort, and the plants will stay healthier for your intervention.

Larisa Walk wrote:Here in Minnesota we don't replant until spring as they aren't fully winter hardy.

Interesting! I'm new to potato onions, growing them for just my second year, but I failed to get all of them up from my first patch when I was moving them to their new bed last September and they survived our -36F winter (about 200 miles north of you) and are producing where they did last year. They seem perennialish to my limited observations.

I don't have perennial onions or shallots (though I want some!), but I do have elephant garlic, chives, and some sort of perennial leek.

The leeks and elephant garlic (which is actually a leek) make little baby bulbs off of their mama-bulb. What I usually do in the spring-- when all the new growth is coming up and I can see where there's too many plants in one spot--is dig up the place where there's bunches of them, and replant (or I could eat) the extras. My son LOVES eating leek leaves, and I use them in cooking a lot. So, I never dig up the plants other than to replant the thinning to get even more leeks. We've yet to reach the point where we have too many.

Long story short: I never eat my bulbs, I just eat the leaves. And I never cure my bulbs--I just replant them in the spring once they pop up and I see too many in one area.

I've now probably reached the state where I could start digging up the bulbs and eating them. But, honestly, I get lots of nearly-year-round oniony/garlicy flavor from the leaves, that I don't really see the point in all the extra work of digging, washing, curing, etc the bulbs.

THOUGH! It could be that shallots are more picky. I don't think any of my walking onions came up this year, and I treated them the same as my leeks. I had a small patch of walking onions for about 5 years, and it just never really multiplied enough for me to spread them out all over the garden like I have with my leeks and elephant garlic.

That's one of the interesting things about gardening.  There is no absolute.  It's about what works in our own garden.  It's fun ( at least I think it's fun) to learn new things, and find out how and what others do, but ultimately we have to figure out what, and how in our own gardens. No two are exactly alike. It's one of the things that make gardening a challenge in a good way.  Even in our own gardens we have to adapt season after season. What worked last year might be a fail this year.

I can't speak for the perennial onions mentioned here, but I have had a clump of chives for years. They did well for a while, but got weaker and weaker over time. Last year I divided them, and replanted them on a spacing of a couple of inches per plant. Each planted chive has popped up with about a dozen new baby stems around it already, really filling the patch in nicely.

I hadn't realised this - the self supressing effect of not dividing them. Lesson learned. I'll be dividing these regularly from here on.

We don't each much from the allium family here, because I'm mildly intolerant to them, so no large patches of onions. Just enough for some greens to eat from time to time  in salads and the like.

Potato onions will indeed continue to grow perennially if not harvested completely. They will be more productive if pulled, separated, and replanted, but even if ignored and left in the ground, they will keep spreading.

This is also true of Syboes or spring onions, walking onions, I'itoi, and so forth. They are true perennials!

I am thinking of creating a second onion bed on the edge of the woods, far from the main garden, and deliberately neglecting it to see how it does when left on its own.

Michael Cox wrote:I can't speak for the perennial onions mentioned here, but I have had a clump of chives for years. They did well for a while, but got weaker and weaker over time.

I'm not surprised. I think most self-propagating alliums would behave that way.

That is, they will multiply from one to many, spread and become a larger, dense patch, but gradually struggle because they are choking themselves out.

However, I don't believe it's critical to divide and replant. Simply thinning them by harvesting should have a similar effect. Be sure to harvest a little here, a little there to get the thinning effect, rather than leave one area bare ground and another one thickly choked.

It seems like breeding in rhizomatous traits back into perennial onions could be a very good thing to help them spread rather than set dense clumps that required division.

One year my potato onions didn’t keep at all because it was too wet when I dug them. I gave up on them because it’s often rainy when they are ready here in midwestern Missouri.  A year or two later, I found a tiny clump in my strawberries. I believe a missed a small one at harvest. I don’t think they had made seed. I let them grow another year and they made a pretty big clump, so I dug them. I bought more from different sources and planted at least  three different strains.   They produced well last year. I may have dug some a little early to beat a rain.  In October a lot of them had a black layer (mold?) under the first onion layer. I replanted quite a few. I tried not to replant the moldy ones but probably missed a few and planted them. Does anyone know if this is a disease they will always have or maybe the soil will always have? They are actually storing fairly well.

Anyway I learned that they can sometimes grow better as a perennial and that my original strain and probably the others are winter hardy in zone 6b, at least most years.  It was the yellow variety from the Maine Potato Lady, purchased about ten years. They get pretty big too. They have good products but charge a lot for shipping, a lot more than flat rate boxes.

Ken W Wilson wrote:One year my potato onions didn’t keep at all because it was too wet when I dug them.

My potato onions/shallots haven't kept as well this year as the previous year, though the potato onions appear to keep better than the shallots. I've lost maybe 10 - 20% of my multiplier onions, which is in line with what Steve Edenholm reports at skillcult. Since they are essentially free after the first season, that is still a very good deal.

I have had good success with fall planting them in zone 4, which lets them get established before starting to rot or mold in a drawer somewhere. I will probably keep doing fall planting for most or all of my multiplier onions.

I was able to buy some Green Mountain Multiplier potato onions this fall, so we'll see how they do compared with other types.