I have some photos of a weed that I'm having trouble identifying. Is that a valid question?
If they're going to crop up and continue to weed about, we should at least edit the titles to be less than generic.
Here's a question title that's too vague and doesn't help external traffic:
What is this weed?
In fact, it probably doesn't help internal traffic when doing a search or browsing the site.
A great title gives you a heads up to what's ahead. Asking a vague question like the above gives none of that courtesy.
A better version could be something like:
Identifying a weed that has stocky roots, thorny stems and blue leaves
Yes, plant (weed) identification questions are a natural part of gardening. In the case you cited, proper identification of the weed is the only way to know how to properly treat for it.
It does raise the problem of duplicates though; having lots of "what is this plant?" questions without any way for that to be especially useful as a long-term resource, with the same plants being asked about repeatedly. It's a limitation of the Stack Exchange software that it's almost impossible to search for a question by trying to find similar images.
In general, Stack Exchange sites are trying to build a searchable knowledge-base of expert information; these questions feel like they'd not be very easy to search though and won't add much value to the knowledge-base.
Plant identification feels like a very niché thing though. Maybe we don't mind as long as it's under a specific tag? I almost want to see a big library of thumbnails of differnt plant pictures so I could search them for one that looks like the plant I'm seeing.
I thought I would post a generic "how do you identify stuff?" question to head off these sorts of questions (and because I genuinely want to know). Gaming is full of "identify this game" questions and I'm pretty doubtful about their value to the site. Not to say I'm against "identify this plant", I just think we should keep them to a minimum if at all possible by referring people to general resources (if any exist). Plant identification seems like it should be easier than game identification.