Not sure what is the problem, but we keep our version of this pruned back like that every year, else it takes over its allotted space. Seems to be ok on it.

Mine is still fairly small.....about 18 inches tall....and we grow it in a pot. Looks fine so far. It flowered beautifully this spring.

Thanks for your replies Owdboggy and Johnp58. My Prunus is currently about 4ft x 4ft and has been established for about 7 years now. It's only the last 2 years I've had this problem. I think the jelly blobs are probably sap and suspect that it's some kind of infection - one where either the plant succumbs or it learns to live with it. I hope to take a few cuttings from the healthy parts next month, just in case I lose the main plant.

We used to get the jelly blobs/sap every year on our prunus and it didn't seem to cause a problem. Then it got clobbered by a really bad winter… As to the leaves dying back - wind burn?

Thanks Moon growe - that's encouraging! Sorry to hear yours got clobbered. So far (fingers crossed!) over 7 years, mine has made it through 2 bad winters. I think it can be more of a problem with too much rain in Devon!

It's growing in a fairly sheltered position and has a huge Clematis growing around the back of the plant, so I'd say it's protected. Also the crispy leaves last year were towards the crown of the plant and this year they are all at the bottom and in the middle, so don't think it can be windburn. If only they could talk!

Two problems to consider, to which your knm is susceptible:

Blossom wilt, is a fungal infection which causes the crispy leaves starting at the tips of the twigs and progressing towards the trunk. Spores are in the air every year, annoying but just prune back to a healthy node - look carefully at the bark of the twig and you may see a change in colour or some wrinkling, go a couple of inches further than that if you can.

Bacterial canker, the likely cause of the ooze, would weaken the plant over several years, and each year flowering would get poorer. Again, prune out, and if you have vertical splits appearing in the bark this is another symptom so prune to well below those. From personal experience this does no favours to the shape of the plant.

For both of these, ignore the risk of silver leaf infection and prune as soon as practical.

Thanks very much for your advice Teadrinker! I will start cutting back asap.