Sterile plants - grow from cuttings not seed

Some plants cannot be propagated from seed as the seeds they produce are sterile. They can only be grown from cuttings from the parent plant. 
The most well known is Bocking 14 Comfrey, the one we all want to grow as it won't self seed everywhere like the other comfreys.

African Blue basil is another one - as I've just found when I searched for seeds!

Are there are any other sterile plants that you know of, please?

Digitalis/Foxglove "Illumination" series sold by T&M (of course) is also sterile!

‘Impossible’ Foxglove named Plant of the Year at RHS Chelsea

Digitalis ‘Illumination Pink’ is a breeding phenomenon
Thompson & Morgan’s new, World Exclusive Foxglove, ‘Illumination Pink’ was chosen from an impressive shortlist of plants to win this prestigious accolade.

‘Illumination Pink’ is a unique and innovative hybrid that according to botanists, shouldn’t even exist! Upon winning the award, Paul Hansord, Managing Director of Thompson & Morgan, said “This plant does everything that everyday foxgloves don’t; it’s reliably perennial, flowers for months on end and has colourings comparable to any exotic flower. This is the only foxglove of its kind and it will shape the foxgloves of the future”. The growing habit of ‘Illumination Pink’ is also very distinct; multi-branching and compact, plants grow to a height of just 75cm (30in), making them perfect for containers as well as borders.

Foxglove ‘Illumination Pink’ is the result of breeding that was considered to be impossible. The UK native foxglove, Digitalis purpurea, has an exotic-looking relative named Isoplexis, normally found in the Canary Islands. This latter genus was classified by botanists as separate from Digitalis, and as such traditional wisdom stated that the two would not make a successful cross.
However Charles Valin, T&M;’s plant breeder, tried the cross in 2006 and was successful. The resulting intergeneric hybrid combines the purple shades of our native foxgloves with the warm orangey colours and jagged petals of Isoplexis.

Digitalis ‘Illumination Pink’ is sterile, so it doesn’t waste any energy in seed production and will continue blooming throughout the summer, often flowering from May through to November.

Isn’t french tarragon one as well?

A few more!

Geranium rozanne
Helenium ‘Sahins early flower’
Lavundula ‘Eidelweis’
Agastache ‘Blue boa’
Erysimum ‘Bowles mauve’

Source: https://www.rosybee.com/blog/2018/8/ster...s-for-bees

According to this research, the plants still produce nectar for the bees, and, because they're don[t realise they are sterile keep flowering, in order to produce some seeds - the fools!! So they have a longer flowering period than non-sterile plants if that is important?

Isn’t french tarragon one as well?

Yes, it is!! I knew there more - just can't remember them.

I would definitely recommend African Blue basil. Had it in dinner tonight and you could tell it was there. We don't bother with other basils now. I need to take some cuttings soon for next year.

Mark, is it easy to grow from cuttings. I'm searching the internet as we speak for suppliers and I can't decide whether to buy one plant or a couple of plug plants! Not much in stock at the moment.

Mark, is it easy to grow from cuttings. I'm searching the internet as we speak for suppliers and I can't decide whether to buy one plant or a couple of plug plants! Not much in stock at the moment.

Last year I put about 8 cuttings in 2 pots and most if not all took. But it didn't take too kindly to being split up and repotted singly. I think I took the cuttings about this time last year and when I potted 3 up separately, i gave 2 away and kept one. The one I kept died. The other 2 lived i was told. But to play safe, I just planted the other pot out without separating them and it (they) is growing well at the moment. So may be it doesn't like its roots being disturbed.

I took several cutting as the previous year, I potted up the plant I had to bring it in to the house and it died on me.

Thanks Mark
I ordered 2 plants but got a bit carried away and ordered another 13 plants from NorfolkHerbs because if you bought 15 plants the P&P was free. Bargain,

Banana has been bred to be sterile.