Locust tree leaf curl

I live in Albuquerque NM about 5000 feet elevation. in general I have good soil. I have several Locust the purple and white flower variety. The Purple does seem to have a problem with a fungus each year where its leave get splotchy and white. I do have a single problem with another variety of locust which I cannot tell you the exact tree name. the leaves are curling up like when you might stretch out your hand flat and then curl up your fingers into a fist.
the leaves are still green but the tree will also loose half the leaves. the tree is about 3 years old about ten feet tall and espicall slow to grow compared to the other varieties of Locust like the purple. I give it a deep watering once a week I have given it a tree fertilizer spike at the beginning of the growing season and later on some fish fertilizer toward summer. When I plante it I made sure the roots were in a good sized hole with fresh garden soil.

I realize my "post" is at least 2 months after you first asked your question; however, I just joined the forum! As I have over 30 years professional experience as a biologist/forester, I thought I would still try to answer your question in the hopes the info will still be of use to you and/or someone else.

Based on the description of most of your locusts, it appears that you have both New Mexico locust (Robinia neomexicana ) (which has "purplish" flowers) and black locust (Robinia pseudoacacia L. ) which has "whitish" flowers. However, some of your trees may also be honey locust (Gleditisia triacanthose) (which has "greenish" flowers). All three species are native to New Mexico.

From the perspective of the plant which is proving "troublesome", my guess is that the plant is either some variety which is quite "exotic" to New Mexico and/or the care of the plant is causing it to be "slow growing". In other words, although you noted that you excavated an extra large planting hole, it sounds like this plant leads a "pretty good life" when compared to the other plants. Consequently, this particular plant has no "incentive" to spread its roots, extend the height of its crown, etc. However, I may try "weaning" the plant for a couple of seasons rather than simply "cutting off" your supplemental watering and feeding "cold turkey". Good luck!
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thanks for the reply. I have removed the tree and replaced it with a plum that grows well in this climate.