Sounds like it is on the way out, so it wouldn't hurt to cut it off and see - and get your shovel ready for a replacement...
The reason it is pruned right after flowering is to assure that it would set bloom buds for the next year, as opposed to trimming it late in the season when they wouldn't have time to form.

Thanks horster for the speedy response. I was aware of the reason of pruning right after flowering, however, it's good to remind me of it, I suppose, I don't want to lose the plant, for sentimental reasons obviously :-)

We had actually another philadelphus (bought on the same time as the one above). It also developed one stem. And flowered every year on the same gnarled stem, albeit weakly, until I shovel pruned it. So, I might just cut it off and see...

i have one doing the same.. among 4 or 5 of them ...

i was going to cut it to the ground... whats to lose???

i cant really think of these old heirlooms.. and you say nothing about it being some foo foo variety ... of these old heirloom plants ever getting too old ...

the others of mine are huge old ugly plants.. that i could squish with a truck.. and probably not kill ...

and i have one.. snow velvet ... which is going to replace them all .. huge ... highly fragrant flowers...on a nice plant ... i am waiting for the variegated version of it...

ken

It wouldn't hurt to give the old guy a couple shovelfuls of compost and top it off with some mulch, maybe you can get some new roots growing along with a new top.
Ken- thanks for the tip on the mock orange, I added it to my wish list. I was looking for a nice big fragrant variety and I think that ones perfect!

They are fairly easy to root IME, so you could try rooting your cutting since this plant has sentimental value.

Thanks all for your comments and suggestions.
Ken it has sentimental value nothing more.
kato, I've been giving compost for the past years, nothing.
Babs, I'll try rooting some cuttings, thanks.

Here is a before after photo. Sorry for the bad quality....

Gangly scgaggly Philadelphus? Isn't that all you ever get? I have 2 (the species and Minnesota 'Snowflake'), and both are pretty scraggly, the Snowflake not as bad.

I saw an ancient hedge of the species Philadelphus at the Ephrata Cloister, (a homestead from the 1700s not far from here), and the effect, when not in bloom, is that of a gap toothed smile. Anyone who goes should look for them on the stream side of the property.

The species plant here was cut to a 12 inch stump 2 or 3 years ago because the tops were dying. Now I have about 8 shoots, and this is the first year of bloom for a while. I would never call this a robust grower, but it is worth a little fuss.

dzitmoidonc thanks for sharing your experience. Just to be on the safe side, I took some cuttings, before I cut down the "twig". Funnily enough as I bent down to cut it down, I saw the promise of a new shoot in form of a couple of buds. We'll see how would they fare...