Euphorbia problem - flower heads unexpectedly die

I grow a lot of these and it often happens to plants that are just getting old and woody. I then find that the whole plant withers and dies in a year or so. Very easy to replace with one of the many self sown seedlings that must be nearby.
TimB

Thanks for the ideas, folks.

Goringfolly - it is getting quite big now, maybe it is just age. Alas, there are no seedlings. I don't know why, as this plant was a seedling that I dug up and potted on from underneath the parent plant and there were loads of them. Maybe I deadhead them a bit too enthusiastically. I tried to collect some seed last year, but they have yet to germinate. Maybe it is sterile? Do you know how I might propagate it vegitively?

Buzzbee - thanks for the thought, but I think if frost was to blame, then the effect would cover all the flower heads and not just the odd one or two. It also seems to happen over a period of time, rather than the whole lot going at once. I have a sneaking suspicion it's something fungal, but I don't know. It seems to recover each time, so I'll just wait and see i guess!

Thanks both!

Sid.

Thanks for that, Buzzbee. I'll have a go at basal cuttings then.

I think there is another possible cause to individual stems of woody perennials doing this 'die back' thing. I have noticed not only with Euphorbias but also Penstemons, Echinaceaes, Eryngiums and similar woody basal perennials - basal ground level stems and main root joints - the presence of slugs making a 'nest' for egg laying in late winter early spring. Because only individual spikes or stems are affected this suggests the damage is being caused 'locally'. If you can tease away the soil around the affected stem you may well find the culprit. Cut out infected material carefully and your plants should recover. Dare I also suggest a treatment with a suitable slug pellet to ensure eradication, then an application of a more environmentally friendly control - 25 to 40mm depth of coarse horticultural grit spread around the base of each plant given a radius of 250mm (10").