Perennial kale breeding

Some time ago, I wrote a post about the principles of perennial kale breeding. Since then, I’ve been aiming to produce a population of kales that are mid way between the near-sterile Daubenton’s perennial kale and the traditional biennial kale: that is to say, plants that flower enough to breed from but don’t flower themselves to death. I have been increasing the diversity by crossing all my favourite traditional kales with plants that have these traits.

Here is a round up of where I am at. Not all of the results are finished varieties that I’d want to propagate vegetatively, but all have at least one trait I want to keep in the population. The hands in the pictures are for scale and measure 22 cm. Seeds of all the ones above the 2021 and 2022 updates are available on my seed list. Please note that they are all open pollinated, so seedlings will show considerable variation – which is part of the fun!

Purple kale tree

This is perhaps my favourite that I have seed for. It is seven years old and still growing strong: the original stem grew to about 10 cm and eventually died, but others have taken its place and it roots itself by layering, Daubenton-style. The leaves are large, tender when young and, of course, purple. Flowering intensity: low. Flowers: white. Some of PKT’s offspring are similar but with even larger leaves and faster growth.

Here is one offspring of PKT that hasn’t flowered yet.

And one that has, imaginatively titled ‘Son of PKT’. It has the same tall growth habit but a leaf shape that might indicate a cross with ‘Cabbagey’ (see below).

Flowering Daubenton

This is the most similar to classic Daubenton’s with similar leaves and growth habit, but it flowers every year, with a medium flowering intensity. Not a great kale in itself, but good for breeding off, especially for its strong branching habit and short annual growth which give it a relatively neat, dome-like form.

Oak leaf bush

Large, lobed green leaves and a bushy habit. Flowering intensity: high. The parent plant died in the cold winter of 2021 but I still have seeds.


Not in fact a single variety, but one original plant and its nearby offspring, all of which I suspect have Brussels sprout somewhere in their ancestry, giving unexciting but mild, cabbagey leaves. With a very straggly growth habit and moderately high flowering intensity.

Nero di Toscana perenne

A group of plants (originally three) arising from a cross between Purple Kale Tree and Nero di Toscana. Need back-crossed a few times to form a true perennial Black Tuscan Kale. They are generally very tall, reaching over 2 m in 2 years (too tall in fact – need to breed in shorter internodes). Flowering intensity varies from zero to heavy, and obviously the seed I have is from the more heavily flowering ones, but it does show a potential for full perenniality in the group. I have had to give up the site where these were originally planted but I took lots of cuttings and have fortunately managed to preserve all the lines I had on the old site. The flavour is generally recognisably Tuscany-y.

Plant 1
Plant 2
Plant 3
Leaves of 1, 2 and 3 (L to R)

Silver Kale Tree

Leaves a bit bitter, but excellent form. Similar to Purple Kale Tree but with a bushier habit and silvered leaves. Grew in 2021, flowered moderately in the summer of 2022 and is showing strong regrowth.

Variegated Kalettes

Quite excited about this one. It appears to be a cross between Brussels sprout (my allotment neighbour let his flower a couple of years ago) and kale – a combination now being marketed at ‘kalette’. It looks quite ordinary until cold weather sets in, when it starts to become variegated, a feature that persists into the sprouts. Moderate-to-high flowering intensity but regrowing strongly.

Purple Rib

Grew in 2020 and has survived 2 flowerings, despite flowering intensity being much higher than ideal for a perennial kale. Attractive, tasty leaves. Form rather too sprawling.

2021 update

The winter of 2020/21 was a cold one in Aberdeen, with temperatures down to -15 degrees C: testing temperatures for a kale. This was great for plant breeding, in that it weeded out the less cold-tolerant varieties, but less good for individual lines.

A majority didn’t make it. My oldest plant of ‘Purple Kale Tree’ died, but another grown more recently from a cutting sailed through. This is often the case with perennial kales. Unfortunately the survivor plant barely flowered this year so I can’t offer seed for a while. The oldest individual plant to survive was ‘Flowering Daubenton’, adding to its list of impressive qualities. The Nero di Toscana crosses also did well, although this might owe more to them all having had to be regenerated from cuttings last year than inherent hardiness. Plant 2 didn’t flower at all, but 1 and 3 did so I have seed from this line for others to experiment with. This year’s to-do list includes sowing some actual NdT in the same bed to do some back-crosses. One purple-ribbed plant both made it through the winter and seeded. It wasn’t one of the ones that seeded last year, so it doesn’t have a name yet. Come to think of it, I might call it Purple Rib.

Another plant, with greener leaves, both came through the winter and is showing impressive mildew resistance at a time of year when many plants get badly affected – but unfortunately showed no inclination at all to flower. Some others which sprouted last year and survived the winter had the opposite problem: they flowered too much to be considered good perennials and were removed from the gene pool. I also decided to get tough with a tendency to straggliness in one group and removed all plants that were too floppy.

You can’t keep a good perennial kale down though, and everywhere where one has died several more have sprung up over the course of the year. I have thinned these to leave the more interesting and sturdy ones and now have nothing to do but wait to see how perennial they are. For interest, some of the lost plants are described below.

2022 update

A better year for kales, with no losses over winter and a few interesting new plants passing the tests of flowering and growing back. I have also acquired a range of perennial kales, such as Taunton Deane, that I didn’t have before and can now add to the gene pool.

Deep purple

With deep purple, lobed leaves and a rather straggly growth habit. A row of its offspring is growing happily but none of them have flowered so far (2022).

Big leaf Jack

The flattened winged stems of this variety reminded me of Ragged Jack and it had big leaves. Flowering intensity medium-high.

Tall savoy

Tall, upright ‘kale tree’ growth habit, with somewhat savoyed leaves. Medium flowering intensity.

Lobed purple

Another of the lobed-leaf group, this time looking like it has Ragged Jack in its ancestry. Strongly branching. Flowering intensity: low. No descendants have flowered so far (2022).

Big Green Lazy

I ended up evicting this plant from the gene pool. It had big leaves, but the ‘lazy’ in its name refers to its habit of growing very thick, sprawling stems which made it a hard plant to manage. I am now selecting for more compact, upright plants.

9 thoughts on “Perennial kale breeding

  1. Anni Kelsey

    PS I had some seeds from your Daubenton’s kale that flowered a few years back and sent some on to New Zealand (with all the appropriate customs and biosecurity checks and declarations) where they have been gracing the garden of a lady I had previously stayed with there, and she has also distributed them to her friends.

  2. Alan Carter Post author

    Glad to hear that they’re getting around 🙂 To give credit where it’s due, the original flowering of a Daubenton’s was in Graham Jenkins-Belohorska’s garden, not mine – and a lot of work to increase the diversity of the line was done by Chris Homanics.

  3. Hong Tan

    Marvellous and better still,it is perpetual. Could I get some of your purple Kale Tree seeds and or your Lobed purple seeds. Thanks,Alex Tan

  4. Graham D Jenkins (Formerly Jenkins- Belohorska)

    So interesting to see your work with this line. It’s been a few years since those first crosses to Daubenton, and so much work has been done by Chris developing the grex, and others like yourself who continue to grow this project. And it’s great to see how diverse its become. But it’s also nice to see the influence of those plants I grew all those years ago still in this material. I particularly like to see the variegated plants, as I lost the line that trait came from some years ago. It shows the importance of sharing material freely in protecting the diversity you are working to develop. If I’d kept those seeds to myself that beautiful trait would be gone. It came from a single plant of Variegated Collard I grew from seed from the US. It was a plain green, open hearted, cabbagey looking plant, much like the rest of its siblings until winter, when it developed white varigation with a slight pink blush on the new growth. I crossed it to Nero de Toscana, and the trait was dominant in its F1 offspring. I intended to develop a variegated Toscana but then Daubenton flowered at the same time as my F1 cross and it was crossed into the Daubenton project instead. The varigation is due to the loss of chlorophyll so shows as white in the green plants and red/purple in those plants that produce anthocyanin. It’s such a pretty trait and I’m really pleased it’s still around. It’s also great to see you building on the incredible work Chris has done, and to see you sharing this seed freely in the same spirit of cooperation that this material grew from. I really respect everything you’re doing here in sharing your work and look forward to future updates

  5. Tamara O'Hara

    My Nero di Toscana perenne is in its 3rd year and is flowering, hopefully the x will be with its neighbouring walking stick kale. It’s been so delicious but this year’s leaves are tiny whilst flowering so I think this is it’s last year. We’ll see but I’ll definitely save the seed and grow the babies next year. I have a photo oh it in flower but can’t add it, tell me if you want it for your own curiosity.


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