Agreed with the tag not being allowed. As per the tagging rules:
Presence- In general, do NOT tag something unless it has a fair amount of presence in a gallery. Anything found in only 1-2 images should almost never be tagged. Example: 10+ out of 80 images or at least 25% would be sufficient for tagging, more so if they are sequential.
The growth is so minor that it's unnoticable as well that it doesn't deserve the tag. That being said this is labelled as "part 1" with no indication of any ongoing or work in progress. It doesn't look complete as of this moment but at the time the tag is not rightly fulfilled per the rules.
When and if this is updated to show more of the growth or have more pages of it being grown, I'll reverse my downvote on the tag.