Benefit of briar accessories?

[winged ember]

Anyone know the full capabilities of briar accessories? My understanding is that they give +1 AS to the briar buff, and drain extra hp to feed the briar weapon... do they do anything else? Flare strength/intensity/etc?

I found it hard to locate a definition on the wiki that seems both official and comprehensive.

The "briar flare items page" says "In addition to their original weapon form, briar flares are available on armor accessories." -- do they give reactive flares at the worn location?