I think in your case this is the biggest issue. You are accessing private spaces in the course of your work, and there’s an implied confidentiality there. (Always socially and ethically, sometimes also legally.)
For a more extreme example, the water heater in this house is accessed through my bedroom closet. If I have to have a plumber out to work on it, that does not give them the right to post the contents of my closet online, with a location, so the whole world can see who’s closet this stuff is in. Maybe there’s something burglars would want to steal, an embarrassing costume, or simply evidence of my poor housekeeping skills on display. It doesn’t really matter what or whether it was anything they knew would draw unwanted attention, the issue is that they gained access to a nonpublic space as part of their work, took personal photos of it, and shared them online.
If (fictional example, I don’t have one) they posted on their social media, “I wonder what’s in this large locked safe I saw while working at this address, but it’s in a private home not accessible to the public.” and then my home got burglarized, I would absolutely be blaming the plumber as well as the burglar.
And if a surveyor posted black morels in my woods with the location public but a meaningless disclaimer about it being on private property, and this resulted in mushroom poachers descending on my woods, I would be blaming the surveyor as well as the poachers. They had no right to share private information like that.
A tulip tree is unlikely to draw trespassers (unless it’s unusually massive) but it’s still important to get permission. A more common concern would be what might show in the background. Maybe their back yard is on the junky side, their children or pets are playing in the background, their underwear is hanging on the clothesline, or another plant that would draw poachers is also visible in the photo. As long as none of that is the case, I expect permission to share the location of a tulip tree would be readily granted by most homeowners.
A tree in the front yard, visible from a public right of way, seems fair to post under the usual tradition that anything visible to the public can be photographed without permission.