Perennial kale breeding

I notice it’s been five years since my last post on perennial kale breeding. Enough time for some progress surely? Happily, yes, and I now have an abundance of seed to share with anyone who wants to join in. 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.

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. Some of my favourites haven’t flowered yet: these are the ones that I have been able to collect seed from this year. The hands in the pictures are for scale and measure 22 cm. Seeds of all these and a few more 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’s

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.

Deep purple

With deep purple, lobed leaves and a rather straggly growth habit. Hand for scale.

Oak leaf bush

Large, lobed green leaves and a bushy habit. Flowering intensity: high.

Lobed purple

Another of the lobed-leaf group, this time looking like it has Ragged Jack in its ancestry. Strongly branching. Flowering intensity: low.


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

Tall savoy

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

Big leaf Jack

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

Big green lazy

Not an awful lot to recommend this one, apart from its large leaves. It’s quite susceptible to mildew at this time of year, although the younger leaves that I pick are unaffected. Long, floppy stems that mean that it forms a thicket. Medium flowering intensity.

Nero di Toscana perenne

Three plants 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. All three are very tall, reaching over 2 m in 2 years (too tall in fact – need to breed in shorter internodes). The first flowered strongly this year and, for obvious reasons, this is the one I have seed for. The second flowered very lightly, which would be perfect but unfortunately I only managed to collect a tiny amount of seed. The third (the most NdT-like) has not flowered at all. I have had to give up the site where these were planted but I have taken lots of cuttings, so fingers crossed.

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

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.

6 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


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