lawn sprinklers SPRINKLE lawn ..

trees need proper deep watering .. and then full drainage.. which is where the clay soil comes into play ...

i suspect its parched.. but i would take a hand trowel.. and dig a couple small holes in the gob planted.. AND FIND OUT.. and then water accordingly ...

be nice to have some more facts.. like when planted.. how.. soil amendments.. perk test etc ... is it mulched?

BTW: and if it was planted after leaf out.. this might just be stress related to that

ken

https://sites.google.com/site/tnarboretum/Home/planting-a-tree-or-shrub

Ken,
It was planted last late fall/early winter. Soil is native clay of central OK, with an amendment of just a few handfuls of peat moss blended in with the clay. Leafed out just fine and on time, didn’t start yellowing until about mid-late May. We’ve also been in the process of planting grass and there has been a fair amount of seed starting fertilizer applied to the area. Hope that helps a little.
-Brad

so.. its not an established plant ... so its not surprising ... especially if you had any weather issues... like a late cold snap.. or early heat wave.. etc ...

keep it properly watered ... the other leaves there look fine... so it should be ok ...

the problem with BAD clay.. is drainage ... potentially too much water .... so adding peat moss ... a water retaining product.. doesnt do much of anything ... i doubt a handful or 2. is important ...

clay itself is a great soil.. usually high in nutrients ... and a seed falling on it.. will grow just fine ... and usually fert is not necessary.. for a tree in mother earth ... and also.. i doubt the lawn fert is an issue ... and btw.. if you fert your lawn in the future.. the tree will NEVER need anything in the way of fert.. it will have its roots out under the lawn.. and get whatever it doesnt need ...

the usual problem with clay .... is the transplant.. with a gob of peat based media... and how you water it ... perfect watering.. as it is in your soil.. in your yard ... and you should be fine ...

dig a few small holes with a hand trowel.. or tablespoon.. in the gob planted.. and in the native soil next to it.. AND FIND OUT ABOUT moisture 3 to 6 inches down ... and adjust watering accordingly ... i see im repeating myself... thats how important it is ...

i hope it is properly mulched ...

a pic of the whole tree.. might be interesting ...

ken

ps: many peeps might suggest you bare root a tree and plant it in native soil.. to avoid the peat/clay interface issues ...

pps: have you ever done a perk test? .. this would be a good starting point on how to deal with your soil

https://duckduckgo.com/?q=garden+perk+test&t=ffcm&ia=web