were these from a nursery? or did you plant them bare root, or were they potted? are they branched out or did you plant them as just a bare trunk?

I'm experiencing the same thing here in z5... Pear in full bloom, cherries slightly behind, apples just now forming buds, and the peaches are lagging far behind. Usually my peach blooms first!

All of my fruit trees were purchased a local nursery (potted), and have multiple branches. Peach bore fruit last year.

They are still very young trees. i am surprised you got any fruit last year. We had some really bad frosts mixed in with warm days. The frost can kill the flower buds on stone fruit (some varieties are resistant to this). If it hasn't flowered yet, it won't this year. I had 1 of my 5 peaches (giant Elberta) which didn't flower this year, and my Nectarine tree didn't flower either. My Reliance, Contender, and Stark Saturn peaches all flowered, but the number of blooms were much lower than last year.

Surprisingly, the apricots did just fine, and so did the plums. Cherries, pears, and apples are all late enough that they are almost never impacted. Also, i am in Zone 5b, eastern Nebraska, so overall we have similar weather.

^^ Well cr*p. Maybe I should invest in the frost protection blankets and be on guard next spring. I figured frost wouldn't hurt the buds as long as they weren't beginning to open or already open. I have a lot to learn. Well, I suppose as long as the tree is healthy and has good growth this year, that means more support for next year's crop. The peach is a Redhaven.

I am not sure if the apricot or nectarine trees bloomed at the nursery - I brought them home in early May. This is a well-known, extremely reputable local nursery, I would expect they know what they're doing and would have handled the trees appropriately earlier in the spring.

another thing to do, is in the late fall, paint the trunks of the trees with diluted (50-50 water to paint) white latex paint. This will help prevent sun scald, deter borers, and most importantly reflect the sun, so it takes a bit longer for the tree (maybe a week or so) to come out of dormancy. Given the roller coaster of weather that we had, this could have helped your trees and mine. I just got too busy/lazy to do it this past fall.

My 5b Zone many days it was around -31*C and my peaches : Diamond peach, Golden Glory and Empress peaches were not affected. They finished blooming very nicely. My Concord grape vine is very good, my pears are finishing blooming. The only fear I have are "bad" bugs and / or fungus? because all chemicals are banned in my place. I fear from peach tree borers and not from under -30 degree celsius?

^^ Our air temps didn't get that cold this past winter, but I'm not sure about the wind chill.

Yovan, can you give us a general location? 5b is a pretty wide band. Both mxk3 and I are in the Midwest and we had freezing temps while the buds were forming (before they opened, but while forming and swelling). We definitely had -30 C weather here, but that is fine since it was while the plants were fully dormant (really close to the limit for a lot of my fruit trees though). The issues we have seen are from freezing temps while the plants are coming out of dormancy and the buds are developing (through opening).

Grapes open much later in the season, so they are not impacted by late frosts.