One of my favourite perennial vegetables has to be toon, sometimes called Chinese mahogany or “beef and onion plant” which refers to the flavorful leaves that taste almost umami, a bit like french onion soup. It the only temperate species I know from the Mahogany family. Young shoots and leaves have a long tradition of use in Chinese kitchens and are today grown industrial scale as “tree vegetable” in greenhouses all year round. Eric Toensmeier did a review of nutritious vegetables and Toona sinensis came in the very top five of all known edible plants - a so-called “super abundant” species that is high in many minerals and vitamins and comes into the very top in both vitamin A and vitamin E.
Growing-wise it seems to love lots of heat and a sheltered space (veeeery long leaves). My plants grow best in the city garden compared to the colder nursery space.
Here you see the shoots at the perfect stage for harvesting in early May (peak perennial shoots season)
My goal is to get reliably hardy Toona sinensis for my climate. As always with woody plants that are on the edge climate-wise, the challenge is not so much our winters (mild) but that our summers are not hot and warm enough to mature the wood before the onset of winter.
Consider the two 1-year seedlings below. Both about the same height. The one on the right has around 50% green wood on the stem. When frost comes, that wood will almost certainly die back, leaving only half the height for next year. The one of the left has almost fully matured, which gives a good chance it might not die back and thus will continue to grow from the top shoot.
Amazingly, not even the top shoot died back, which meant it continued to grow straight up instead of getting two competing shoots from below as trees often do when they die back. Here the same individual in July 2024 (now in November it continued to grow a meter more or so). I probably reached 4-5 meters.
Grow seedlings first year in large containers in greenhouse (100 seedlings in one box). Next year I want to increase that number to hopefully 400-500.
Select among seedlings at the end of season for early maturing wood. This year I picked out 5 individuals with stronger growth and fully mature stems from those 100 seedlings.
Overwinter first winter
Plant out in spring
Allow the best individuals to grow tall (doesn’t die back in winter) with the hope on getting tall enough trees to eventually get seed
Grow on less-good individuals as pollards (die-back in winter as a form of self-pruning) which makes it easy to pick new shoots. I probably won’t get any seed from them, so the breeding effectively stops there, but I still love to eat the leaves.
I have a single tree that is about 3 years old. Each year the frost kills back the main stem and it regrows from slightly further up. I wonder how that will affect it later on. I planted it in quite an exposed area, with hindsight, a mistake.
How do you germinate the seeds? Where do you get seeds from?
Most of the trees I have planted out behave in this way. Some of them are starting to look like multi-stemmed trees or bushes. I only started grading seedlings this year and expect I will have less of the newer plants behave like that because I’ve selected for early maturing wood.
I ordered seed from Vreeken’s Zaden in Netherlands. You can buy seed in bulk. They use it for micro-greens. Quite crazy. I know one restaurant in Netherlands that feature this plant on their menu, and there might be more there now, but otherwise I don’t know anyone in Europe that grows this plant for market. I think it has huge potential obviously. The seed germinate really well. I think the seed source might be local since they sell it by the kilo if you want.
The seed quickly loses viability. First year I have just sowed them in a warm place (green house) late in season and got good germination. Now I cold stratify the seed 2-3 months after having stored them for a few years to help germination. I soak them for 24 hours in warm water before sowing. Warm temperatures help germination and 25C seems optimal.
I consider getting fresh seed again because this season I had less germination than previous year.
I don’t understand what knotting into a bush mean.
I’m very interested in this species, but I keep on reading that the flavor tastes like onions. Occasionally, though, I hear people saying it tastes like garlic instead. Does it really taste like onions, or does it just have an umami-ish flavor?
I intensely dislike onions, but I love garlic. To me, they taste nothing alike. I think the difference is probably sulfur, because durian and jackfruit also taste like onions to me, and they’re apparently high in sulfur. So if toon has a sulfury taste, I would probably not like it, and if it doesn’t, I would probably like it.
I would describe it as sulphuric. I’m surprised you don’t register a sulphuric taste in garlic though as it contains a lot of allicin - one among several sulphuric compound responsible for that characteristic smell and taste.
Describing flavor has some challenges. For me, the taste of toon reminds me of meaty stock, plants in the Alliaceae, browned onions and maybe fried butter. Deep flavors. It probably doesn’t contain any glutamates (signalling true umami) but flavor compounds that remind us umami, which psychologically gives you some of that experience. I would recommend you to try it and judge better yourself whether you like it or not.
A question I’m looking for an answer to: When does Toon typically come into bearing, ie. how old or tall does the tree typically grow before it will set seed?
