I'd likely ignore the nitrogen issue this fall. But if the tree isn't growing, applying some nitrogen won't hurt. You are just down the road from Scott and the winter weather there is pretty mild.

I won't ignore the potential over watering issue. You only need to rewet the rootball that was planted. You aren't trying to recharge the water table. So ease off on the water. When watering a newly planted, potted tree, frequent small waterings to rewet the rootball is the right approach. One gallon will do that.

Contrary to the literature, I have not found post-Aug Nitrogen applications capable of stimulating new growth and even Aug applications only cause rank growth on branch tips- the rest of the tree seems to harden off in a manner unaffected by the late growth. I wish someone would do some research on this issue because I feel it is one of those things that gets repeated by academics without any specific research to back it up.

Now, on your question, I agree with FN that there is no point in fertilizing now and also that it wouldn't hurt, might even help a tiny bit by getting some into the buds for a slightly quicker spring flush although I don't notice this affect on fall fertilizing of peaches. Probably just as well to wait until first growth in spring and then supply another application in early summer.

With trees in potting soil it is easy for them to dry out when first transplanted and that could cause a quick change in leaf color- so it could just as well be too little water as too much. If finer soil around the coarse texture of potting soil is dry it will suck out any water from the potting soil by capillary pull drying it very quickly. At the same time, the coarser mix can't pull water from finer soil. This is a complication with planting potted trees. With peaches I find bare root trees tend to establish faster.

Any tree stimulated to grow in the fall will be vulnerable to frost damage in the winter because the new stimulation will slow the dormancy reaction. Let it go dormant and then stimulate in the spring.

Here is a link that might be useful: Garden For Nutrition

Green Garden, I'm well aware of the theory- that is my point. The theory is often stated without any clear evidence of what the cutoff is in creating this kind of reaction and to what extent does it actually affect hardening off of the entire tree.

I've seen the result of drought here where rain comes in mid-Aug and causes a sudden burst of growth on many trees in my nursery of many species of fruit followed by a harsh winter with temps in the -15 to -18 degree F. range. The only damage has been to those growing tips. How is this different than a nitrogen application? When it rains after drought there is a burst of available N along with the water in any soil with an appreciable amount of organic matter.

Carl Whitcomb disputes this theory in his book "The Establishment and Maintenance of Landscape Plants" where he states that N. is incapable of taking plants out of their normal cycle of dormancy after late summer. He is an advocate of fall fertilization of trees. Google his name to learn more.

I regularly fertilize fruit trees with a shot of N in Sept and Oct and it never leads to a burst of new growth. Hundreds of trees-many sites. Just did over 100 container trees with urea yesterday.

Funny, I often hear advice not to water after a certain date, but here near Portland, Oregon the rain keeps the soil moist from September to July.

Well I think the claim is that the trees head to dormancy earlier in dry soil and survive harsh winters better- not much an issue in Portland.

Winter hardiness is not a completely understood phenomena (and I'm not just talking about myself).

Spots this time of year is bacterial spot. The leaves are getting ready to fall and the plant slows down feeding them nutrients and they become very susceptible to diseases. Don't worry about it.

Scott