Old-school style beach plum jelly is made without any added pectin. When gathering them in the wild make sure to include some under-ripe berries. A long simmer makes for a good strong set. It's a sticky jelly with a good puckery punch.
There can't be beach plums in Oregon because otherwise there'd already be an episode of Portlandia dedicated to cult of Beach Plum Jelly: foraged locally, strictly seasonal, old-timey recipe for an odd yet nonthreatening jelly, now with reduced sugar