Average time from budswell to budbreak European hornbeam?

[Scrogdor]

This is my first spring the buds on all my trees are beginning to swell/ some have leafed out. The time from budswell to budbreak has been pretty short followed by some explosive growth, except for my European Hornbeam.

The Hornbeam in question was the first tree to actually start having buds swell, but it’s now been three weeks and they seem suspended in animation.

I’m just curious if those with experience can confirm if this is normal behavior for Hornbeams or if the the tree is being stressed out by something. Some pictures below of what the buds have looked like for at least a couple weeks now.

Unrelated - some kind of larvae was in a big terminal bud at the top of the tree, I noticed when the bud opened up but never leafed out last month, it must have been munching the top there for a while.

 

[0soyoung]

The whole process is temperature dependent.

When (what date) did you identify bud swell to have begun? Is the answer just 'at least a couple of weeks ago'?

 

[Shibui]

Each species has its own general timetable but those general times can be skewed by local conditions and care.
I would not be worried while the tree still looks healthy.