There is a bare strip of dirt between your sidewalk and the curb, and a tree would obviously improve it. Shade, birds, a street that looks like somebody lives on it. So you buy a sapling and get a shovel.
Stop there for a moment, because that strip is almost certainly not your land, and the tree you put in it comes with an obligation that outlasts your interest in it.
The strip is public, the work is yours
Portland's Tree Code names the strip between sidewalk and street for what it is: the street planting area within the right-of-way. Public land. The city owns the ground, and cities generally treat that strip the same way. That fact leads people to a conclusion that turns out to be exactly backwards: that the tree in it must therefore be the city's responsibility.
The cities we have verified say the opposite, and they say it clearly.
Portland puts it in the Tree Code: property owners are responsible for maintaining trees on their property and on the adjacent street planting area, the right-of-way, per Title 11, with maintenance specifications and responsibilities at §11.60. Seattle's street tree page states the deal directly to whoever plants one: "you are responsible for all future maintenance and tree care, including watering during the hot summer dry season, mulching, pruning, and protecting your tree from mechanical damage." San Jose likewise assigns street-tree maintenance to adjacent property owners.
The city owns the dirt. You do the work. That is the arrangement in every jurisdiction we have documented on this question.
Why cities regulate what goes in the strip
A tree in the right-of-way is not landscaping. It is infrastructure sitting in a corridor that also contains sight lines for drivers and pedestrians, overhead utility lines, and buried water and sewer mains.
Species choice is where that gets concrete. A tree whose mature height puts it into the power lines becomes a utility's pruning problem for the rest of its life, generally resolved by cutting it into a shape nobody wanted. A species with aggressive roots in a narrow strip becomes a lifted sidewalk and possibly a compromised lateral, which is the failure we cover in the root damage guide. A species that cannot handle the local climate becomes a dead stump somebody has to pay to remove.
That is why cities maintain approved species lists and control placement rather than leaving it to whoever shows up with a shovel. The specific list is local, and it is genuinely local: a list built for the Pacific Northwest tells you nothing useful in central Texas. Get the one for your city from the city, and be wary of any page that claims to tell you what is on it.
Permits: assume yes, confirm locally
Because the strip is public land, planting in it is a modification of public property, and cities typically require permission before you make one. What that permission looks like varies enough that we are not going to describe a generic process as though it were universal.
What we can tell you honestly: the records we have verified establish the maintenance duty in detail and do not capture the permit terms. So the permit question is one to put to your city's forestry or urban forestry desk directly, and it is worth asking before you buy a tree rather than after. Planting without approval risks removal at your expense, and removal is a worse outcome than the empty strip you started with.
Ask what species are approved, where the tree may sit relative to the curb and any driveway or corner, whether utilities need to be located first, whether the city plants it or you do, and what happens if the tree fails in its first year.
The duty you inherit
This is the part that outlives the enthusiasm.
Seattle's language is the useful specification here, because it describes actual labor rather than an abstraction: watering through the dry season, mulching, pruning, and protecting the tree from mechanical damage. That is not one weekend. Young street trees need consistent water through their establishment years or they die slowly and expensively, and the summer they most need it is the summer you are least likely to be thinking about them.
Portland runs a city-funded Street Tree Care program covering inspection, pruning, removal, and replanting, which is real help and is worth using. Note what it is, though. The program supplements the owner's obligation. It does not replace it. If your city has something similar, read it the same way.
The duty also runs with the property rather than with you. Sell the house and it transfers to whoever buys it, which is either a gift or a liability depending on how well you handled the establishment years.
So should you plant one
Yes, if you understand that you are volunteering for maintenance on public land for the life of the tree, and you are the kind of person who will actually water it in August of year two.
No, if what you want is a tree you can do whatever you like with. That tree goes on your own property, where the species is your choice, the pruning is your schedule, and nobody else's code applies.
Either way, one call to the city forestry desk before you buy anything is the difference between a tree that stays and a tree that gets removed at your expense. Ask about the species list, the permit, the placement rules, and whether the city has a care program. Then plant.
Rules on trees, sidewalks, and who pays when they collide vary sharply between cities. Browse by issue to see what we have on the record for yours.