Yucca Rescue ?

After its spectacular flowering display last autumn, our largest yucca gloriosa went into a serious decline over the winter.

It was suffering from a fungal infection which shows itself as brown spots on the leaves.  It's happened several times before to a lesser degree and, although there's no cure, the infected leaves can be simply cut off leaving the unaffected ones on the plant.  

However, this time around, every single leaf was discoloured.   Previously, these infections had also started during the winter months, particularly in prolonged wet periods, but last winter and early spring had been remarkably dry.

I first thought perhaps that yucca were monocarpic, i.e. they flower only once and then die, but then I remembered I'd seen very much larger specimens in flower in the Canary Islands, and in that climate it seemed unlikely they'd reached such a size without flowering several times before.

So what to do with the plant ?  A bit of research on the internet seemed to suggest that the top of the plant could be cut off and, with a bit of luck, it may respond by producing new shoots from the side of the trunk.

So in late April, during a spell of warmer weather, this is exactly what I did, cutting the whole head off the plant and leaving a bare stump of 300 mm height.

the freshly cut stump ...

and the infected leaves on the cut head ...

As an afterthought, I also cut a 75 mm slice from the base of the removed top, and put this into a pot of compost, topped off with gravel to anchor it.  Maybe this 'cutting' would take root and also produce new top growth.

the fresh cutting in a pot ...

Our other large yucca, currently residing in a big pot, also showed symptoms of the same affliction, but on this one only the outer leaves were affected and they were all removed, leaving an array of healthy leaves at the centre. 

So then it was just a question of waiting.  The top of the cut stump dried out very quickly, and blackened and shrivelled for several inches down from the cut - I really thought it was dead.

But, just a few days ago and over ten weeks since the chop, I noticed several new shoots bursting out just above ground level - there are five in all, with four very close together.

the shrunken top, but with new shoots at the base ...

four of the shoots ...

I'm very pleased with this result.  It'll be interesting to see how much growth these shoots can put on before the winter.  It might be better to cut a few of them off, so the plant can focus all its energy on those remaining, but I'll wait until they've all put on some more growth and then decide.

And the cutting ?  Well, it also blackened and dried out quickly.  It appears to be totally dead, but if I pull it upwards very gently there seems to be some resistance and so maybe it's started to take root, or maybe it's just held down by the gravel ...  

the cutting today ...

Anyway, we'll keep watering it until at least the end of the summer in the hope that there's still life.


Update 26-Aug-19

Another couple of fresh shoots have appeared around the stump in the ground, in addition to those emerging from the stump itself.

new shoots from underground ...

One of these new shoots has grown away very quickly, the larger one on the right.  I'm currently working away and so I didn't notice this at all until last Friday, when I came home for a whistle-stop visit.

And, the 'cutting' in the pot now has three shoots coming up at its sides.

three new shoots emerging ...

All in all, it seems to have been a successful rescue of a plant I'd thought I'd lost ...