Potato Plant not blooming

Does anyone have any ideas why my potato plant is no longer blooming?. I have three of them on trellises facing south, lots of sun, plenty of water, which I have recently reduced.
One plant went in a year ago, and was blooming fairly well; I then added one on either side of it, (these are to cover a side of a shed) and these had a few blooms too when I bought them.
Foliage all over the place, but few blooms. I reduced the water, and have been spraying Neem, as it looked like something has been nibbling on the bloom clusters long before they are ready to bloom. But there aren't many clusters. The greenery is about 7-8' tall. I live in Northern Calif. and we get only about 11-14" rain a year anymore, so I supplement with little drip irrigators, which I have reduced. HELP!!

Just want to make sure I'm understanding right--the one you planted last year is blooming fine, and the two others were planted this year and aren't blooming well? If so it's probably just that they're taking time to get established--plants will generally work on getting their roots going first rather than focus on blooming. I have potato vines that I planted last year and they didn't bloom much at all last year, but this year they're blooming more (although still not as much as the vines that I planted the year before that).

Actually, the plant from last year was blooming some last year, and a little this year, as were the two that I put in the ground this year. The two new ones had some blossoms on them when I bought them and bloomed a bit more later, but now nothing. How much water do you give yours? Someone told me she just "abuses" hers and they bloom like crazy, but they have been in the ground for awhile. As I said above, I know some critter was chromping on the tiny, tiny pre-bud clusters, and now I think I have that in hand. I had the same problem with my bower vine and after spraying regularly with the Neem there, I am getting blossoms. But with the potato vine,
nada. thanks

Once they were established, mine get watered once a week. Until they're established they need a bit more though. If there are critters chewing off the buds that may be contributing to the lack of blooms, but sometimes things just take a little more time to get going. I have two sets of potato vines--the first set for whatever reason took off and got blooming well very quickly (within the first year it was in the ground), but the second set is being a bit slower. I planted them last spring and they hardly bloomed at all last summer, and even this year they're blooming but not nearly as good a show as I got from the first set at the same age. There's really not much difference in the conditions they're in (same amt of sun, water, etc) and they all came in 1 gal pots and were about the same size when I planted them, but I'm still seeing variation in how long they take to get going. So I'd keep an eye out and treat the bugs, and then just be patient and see how they do next year.