I got confused and misspoke. It seems that Barriers (Feature Type: Barrier) CAN have a Type subfield planter (tag barrier=planter). But what I meant to say that is that a Planter as a node can remain unchanged with a tag barrier=yes but when a Planter's tag is changed from barrier=bollard, the Feature Type changes to Bollard. But all of this is irrelevant anyway; I was looking for the perfect combination of tags to account for the types of planters/barriers I saw in person and got my tags mixed up.