Ruminations on Rakkyo
Rakkyo (A. chinense) is a Japanese multiplier that produces small bulbs, on average about 3/4" tall and thick. Many of the canned and bottled commercial "pearl onions" actually are Rakkyo---the Japanese export hundred of barrels of them every year.
It's a perennial allium that is normally planted in mid- to late August. It then blooms in October (pretty pink flowers which do not produce seed), winters over in the ground, then forms bulbs in the spring/summer. It's lifted in July, when the leaves start to die back, and the process starts over. Or it can be left in the ground for a short hot weather dormancy, then allowed to grow again.
I've been going through a number of "what ifs?" with it, that may or may not have ramifications for other multipliers.
For starters, I wondered what if I didn't plant until the fall, treating it like garlic. Low and behold, other than missing the floral display, it bulbed at the regular time, with normal divisions and bulb sizes. I regularly see 3-13 bulbs, with 4-5 on average.
So, I started skipping the August plantings, because I hate being out there in the heat and humidity if I can avoid it.
This year, due to the monsoons of last year, I didn't get to plant until January. If anything, the crop is better than ever. I lifted the crop today, and found each bulb had divided into from 3 to 14 new bulbs, with an average of 7 in each bunch. Overall sizes were within the normal range, but there were proportionately fewer undersized bulbs.
Unanswered question: Would this be normal? Or was there something about this years moisture/nutrient/sunlight mix that caused the better harvest. So that's another what-if that needs to be addressed.
Another one, which I'll save for next season: what-if I don't lift them in July? Each bunch will grow, I'm sure. They are, after all, perennials. But will they still form bulbs? And, if so, what will happen to the sizes? I've never left them in the ground for the summer dormancy, so haven't a clue. Someone once said that leaving them to grow a second year produces larger bulbs. It will be nice to find out.
But all this has me wondering about other bulbing multipliers. I didn't get my potato onions planted, this year, until March. When I lifted them last week they were, on average, smaller than usual. The sets were tinier, and the full bulbs nowhere's near the 2 plus inches I've come to expect.
Part of this may have been sunlight; the POs were in partial shade. Part of it may have been how late in the year they were planted, as compared to my usual practice of fall planting. I suspect it was the shade, more than anything else, but don't really know the answer. Yet.
But I'm wondering what will happen if I plant them in January? So that's another what-if. And, because multipliers are essentially perenials themselves, what would happen if they weren't lifted. What if I let them just die-back for a summer dormancy, and regrow again when they're ready? Will I wind up with an alliums perpetual motion machine? Or will they degrade to bulbless bunching onions?
Another what if: We know that the best production for shallots is to plants the smallest bulbs. And shallots are nothing more nor less than specialized multipliers. What if we do the same with Rakkyo and Potato Onions? Will the tiniest "sets" produce the largest full-sized bulbs? That's certainly what happens with sets from common onions. Or will they act like garlic, in which the larger cloves produce the larger heads? Or doesn't it matter at all?
All of this is one of the reasons I love multipliers so much. There is tons to be discovered. And there is, basically, no body of literature on the subject. Most of what we know is from sharing personal experiences here at the Alliums Forum, and at similar sites.