Funny, Acontifolium was about the last of my JMs to leaf out. Mine has had a tough time. It did well growing in a container, but was continually attacked by deer after I set it out in the yard -- my only JM to suffer deer damage. So I dug it up last summer and repotted it and put it on my deck where the deer can't get to it. I hope it survives as it once was a beautiful tree.
A tour of the garden today found that Acer calcaratum, Acer pensylvanicum 'Erythrocladum' and Acer conspicuum 'Phoenix' are still at the bud stage. Acer henryi is bud breaking (griseum, triflorum, pentaphyllum,... are already in leaf). I was also amazed to still find an A. palmatum just breaking its (tiny) buds: 'Shin higasa'. When one takes into account that the first palmatums ('Goshiki kotohime', 'Koto hime', 'Katsura', 'Komon nishiki', 'Kokubunji nishiki' and some others) were in leaf on February 20th, that gives full two months between the first and the last palmatums. Gomero
Palmatums in leaf in February takes some beating My own trees are only just beginning for real about now Senkaki is leafing out well Katsura is just opening And the rest are trying hard to follow A couple of weeks and I should see real colour So, really, May is the beginning here in the North of Ireland
Most of my JMs have now full leaves, however, as Dawgie indicates, the Aconitifolium is still leafing out some leaves. It began 2 months ago, but still it has more buds breaking. Looks like it will need whole spring to leaf out completely. It's my first season with the Maiku haku, so I don't know yet its behavior. Nelran