Sometimes it is the only thing I can make obs of. Oftentimes I’m in an area where weeds or invasive plants have taken over and then it is almost impossible to find anything that is not common. I like to have a record of the places I’ve been, and luckily so. Last year I was in an area that have been overrun by Echium plantagineum, but I still got obs of those with white flowers. In the same area, after a number of walks, I saw my first disa, so it made it worthwhile to notice the common plants first in order to draw my eye to what is out there that is different.
The same area is now closed off for a new office block and residential development, so even though perhaps 90% of what was there were common weeds, aggressive invaders, common grasses and reeds, I’m happy to still have made a record of what was left of the original flora of that specific area before it got lost forever.
I sometimes also get to places where I actually do not know what is common to that specific area and then I just try to get as much in as possible. I see once I upload obs what is common to the area and then when or if I can go back, I can focus on the things that is not always easy to spot and maybe a new instance of a common plant or a common plant with some new growth or a new insect on it. Sometimes I think you know what I really do not want another observation of protea nitida, even though I am in a new place and there are a few. Until… one with a gall that is not frequently observed, others with witches brooms and others with leaf blights, which I would not have noticed had it not been for trying to find something else. That made me look closer and discover something new about a plant that is practically as common as grass in some areas.
And of course, even common plants go through changes in seasons and weather patterns, so observing the common plants in an area can give indication of plants that flower earlier than normal, that race to seed or sometimes change their behaviour to respond to some change in weather or seasons or some threat perhaps. Having seen a few hybrids amongst the common plants in an area, of course also adds knowledge. This keeps it interesting.
And some common plants I just plain like, so I will almost always photograph them and upload the obs. Maybe someday what is common now will be scarce or heaven forbid, completely gone.
But I still do not like something like E. plantagineum becoming common in an area where it has no business to be in and no natural way to protect the original flora from it. The spread of invasive species such as these are better seen if, when they become common, there are obs made.