Red growth on rose

Red growth on rose

Observation - Red growth on rose - UK and Ireland. Description: This looks like some kind of red sea weed like frond growing from the stem at the joint with the leaf. At the bottom of the first picture there is an older bit that has faded to a brownish tone. It was in front of a hedgerow on the edge of a road. It is

This looks like some kind of red sea weed like frond growing from the stem at the joint with the leaf. At the bottom of the first picture there is an older bit that has faded to a brownish tone.
It was in front of a hedgerow on the edge of a road.
It is on wild rose.