How Quick is Quick?

I don't know if it's a problem, but these plants behave as their cousins the elders (e.g. elderberry).
With mine, every year I cut out some stems right at the ground, this makes it produce fresh new shoots from ground level.
The shoots grow fast, so I prune them back in summer, but leaving enough growth so they will carry flowers the following year.
Over the course of 3-4 years I aim to replace all stems, so that none are more than 3-4 yes old.

Which is a long way of saying - if it were mine, I'd cut out the dodgy stem completely.
It's fine to do it now.

 

Thank you,@Pete8 for your helpful advice. I've only ever pruned back a few inches to remove all the leaves and weaker branches in Autumn. Maybe it's time for a very ruthless prune and I will start with the affected branch today.
Thanks again.

 

I don't know about the fungus @pattie, but just in case if you have some non-flowering shoots you could take cuttings. I took fairly big ones, put them round the edge of a pot of compost (maybe a 5 or 6" pot) and put the whole lot in a plastic bag on my windowsill for a while. This was probably 10 or so years ago but if I remember rightly, they rooted quite quickly.

 

Ooo, thank you @JennyJB. It may well be worth doing that- something I've never tried before so it will be a fun thing to do.

 

According to Mr. Google they also root in water so just for fun I might try snipping off a couple of bits and popping them in a jam jar or small vase.

 

I used to prune back hard years ago like everyone else but now I prune it similar / slightly different to how pete prunes his sambucas , I've been doing it for a number of years now and find it much better keep the flowers and to help keep it relatively compact for the vigour of the plant .

How I prune mine after flowering i nip the top off down to an height just a bit lower than i want - thin some branches back down to the stump/where it branches which the top of the fence for me - nip some the branches back on the sides and leave it until next summer .

This is mine now which is nearly a year since last pruned, flower are on the way

 

I don't know if it is but the fungus sounds like jelly ear Auricularia auricula-judae - Wikipedia
It is found on elders and is a very common fungus that I see almost daily on dog walks bit admittedly never noticed it on live wood.

I take cuttings of my elders and I have noticed that in the summer the easiest way to do it is to put them in water and wait for the little white rooting nodules to form before I pot them up in a cutting mix and pop in a propagator. I noticed that if you leave them to develop roots that are to long in water then they don't transition to soil as well and by starting them in water it's easier to prevent them from drying out, so the combo styles works well.
In winter you can just take a long hardwood cutting and bury it two thirds in soil and it will likely root, they are as easy as willows that way.

 

Hello @Butterfly6, I wondered whether you've now got your Sambucus and which variety you chose. I'm planning on changing one of my borders and think I need one for contrasting foliage and colour!

 

I’m still pondering @Plantminded. If I do get a Sambucus, I’ll probably go for Black Lace. I can’t quite decide which way to go for the overall look in this bed. I think I’m still getting used to the space and change in light, it’s made such a. Huge difference losing our old laurel tree

 

Thank you @Butterfly6, these decisions need to be fully considered . I’m going to wait too!

 

It so happens that the Sambucus nigra I planted 2 years ago was in replacement of a Portuguese laurel specimen which had grown to become un-manageable. I don't regret taking that action.