Cordyline species

[RobSta]

I've developed a bit of a soft spot for Cordylines recently. Since moving to West Cornwall I'm saddened to see the state of the Cordyline australis that are in varying degrees of stress and dieback.

I think it must have been around this time last year, that Chad said that C.australis might grow better in garden situations where they are given plenty of fertilizer and tlc.

My Cordyline 'Kari Kiri' which I brought with me from my old Surrey garden have remained potted and under cover for this past year. I also have a few Cordyline 'Emerald Star' (aka 'Broadsword') which are still looking good. I wonder if they will survive long term in my next garden.

My question here, is that if I were to select some Cordyline australis from a nursery, and the leaves have yellow spotting, dare I risk buying and planting them out?

More questions. What future is there for Cordyline species in the wet SW of the UK? Do we collect seed from resistant plants?

[charlie]

? mine all seem fine, just random seedlings, I wasnt aware there is a problem, I do sometimes wish I had cut cold damaged stems down straight away as they never look as good going forward

[MartinNicklin]

I have to say the last time I was in Cornwall I was amazed at the splendour of the cordylines. I also have to say that even here in the very cold (by comparison) county of Shropshire, I see enormous numbers of Cordylines looking really magnificent in both stature and health. I have one in my garden which was a tiny 9cm potted plant 4 years ago but which is now taller than myself and has the lushest of leaves probably 10cm in width. I’m seeing more and more locally at house roof height and so, like Charlie, I was also oblivious to the fact that there is a possible health issue with this species.

[Dominic B]

Hi Rob, as far as I am aware (and happy to be corrected!) the demise of the Cordyline australis here in West Cornwall is due to a virus carried by aphid. It has been around for at least 10 and possibly 15 years and all the really magnificent Cordylines and many less spectacular have slowly diminished and died over that time. There were a handful in the Penzance area that had even survived the brutal winter of 87 and they were spectacular and venerable specimens. We have reached the point now where they struggle to establish here and I’m always struck when I go up to the home counties how much healthier they are there. Very sad as they are a beautiful plant and very much part of our landscape down here.

Of interest, in my experience it is only the Cordyline australis that are affected all other Cordyline species seem to be ok.

[Dominic B]

Reading around a little last night it certainly appears to be more likely a fungal infection rather than virus (or bacterial). Certainly prevalent in West Cornwall nonetheless.

[MartinNicklin]

That’s very sad to read and it must be longer ago than I thought since I was last in Cornwall because one of my abiding memories of Falmouth was a street where there was a magnificent Cordy outside almost every front garden. I think it was the street where Fox Rosehill Gardens are to be found.

[Chad]

Dominic, are you referring to 'Cordyline Sudden Decline' which has ravaged native C.australis in New Zealand?

It is diagnosed by finding its DNA, so far the causative organism hasn't been cultured, so it gets a three part formal name; Candidatus Phytoplasma australiense, with the first word warning it is a 'candidate' species.

I can find no reference to it having been found in The UK.

As far as I know, the consensus for the loss of some venerable plants in Cornwall was assumed to be a combination of a cohort effect [several old plants of similar age just died of old age] and a series of inclement, to Cordylines, weather events. The row outside Tesco in Penzance suffered from salt winds in the winter of gales. Several were weakened if not killed outright in the year with a long dry summer, The Beast From the East and then a long wet year rotted some roots.

I agree there has been a significant loss, but I think it may be part of the general turnover. Certainly there are still lots of healthy clumps about.

I don't know enough about the other species, but C.indivisa likes Cornwall and is a signature plant in some Cornish gardens. Mine rocked out in a gale though.

Chad

[Dominic B]

Hi Chad. I am not sure what is causing the demise of the Cordyline down here but I believe it is more than a just series of unfortunate events (eg old age, salt spray, cold winter, etc). The Cordyline’s near to Tesco in Penzance are a case in point. They grew initially very strongly, looked great and then diminished over a series of years. There seem to be very few fine specimens left around Penzance. They start by getting the chlorotic yellow spots and then drop growth points to leave blind stems and often don’t survive (although sometimes they do but never in glory). Something is affecting the vascular tissue it seems. I am sure Steve at Lower Kenneggy Nurseries has more to say on the subject, it would be good to get a clear answer!

[charlie]

When we moved here there was one already here, its only claim to fame is it is sterile and never sets seed, later I grew some from seed I collected on Madeira from a bronze leafed plant we had seen at Quinta Magnolia only one seedling had bronze leaves! I planted it and three others (much to Liz's annoyance as she doesnt like them!) the Bronze one grew for about 4 years but succumbed to a cold winter spell, the other 3 are getting a good size now and flower each year and set seed which I think stops them looking quite as tatty as my original plant, but the downside is baby cordylines all over the garden.

My personal preference is not to let the trunks get too tall, I am not a fan of the "Washington Palm" look with Cordylines so tend to cut out tall stems at about 12' and I do agree with son Chris who thinks they should be kept well away from any grass areas that have to be mown! He does some gardening work and is always complaining how the dead leaves wrap around the mower blades, his dad telling him maybe it would be an idea to pick them up first doesn't seem to go down well!!

[Paul S]

Cordyline australis over this side of the archipelago are generally OK although it seems an increasing number do get spotty leaves and tend towards scruffiness. No idea why.

Whilst we are here, though, it is timely to post this I think as I find it interesting/perplexing. Excuse me using pics nicked off the net, I don't have any of my own. Cordyline australis inflorescences should look like this, yes? It is what they have always looked like - droopy, open panicles.



There seems to have been a period starting maybe 10 years ago when more recent plantings of ostensibly Cordyline australis started flowering and they look like this. Leaves are generally shorter and wider, although not by much.



Stiff, upright, compact things. Totally different. What are they? Cordyline obtecta? It isn't one or two, there are loads - outnumbering the usual form in recent years, I'd say from casual observation.