There are some questions which need to be closed because information in the question is missing (e.g. pictures) and the user has not added the information despite reminders (comments) by other's. We can only wait so long for the user to respond and if they don't we should close it. I suggest adding a category for close reason for this scenario. The current categories do not suffice. What are your thoughts? Are there other ways to close these old, incomplete questions?
I am reluctant to use Unclear what you're asking because it's very clear what the OP asks: why is his tree dieing, how to prune a shrub, where to place a flower container, etc.
I feel that having a message like "Closed because it's unclear what you're asking" on a question that fails to provide enough info (although the question is comprehensible) only annoys the OP and brings insecurity to potential new askers.
Having a different message, something like "Closed because of insufficient data - it will be reopened when new info is added" might be more user-friendly in my opinion.