Connie Arnold of Hamilton, Ohio sent me these images of English ivy in bloom on August 9th. This puts the bloom at about 2427 GDD.
If you have access to an old English ivy plant and can inspect for bloom, please do so as the phenological wave moves north over the next few weeks. Send me a picture if you can, along with the date and zip code of the plant and whether the plant is at first bloom or full bloom (one out of 20 buds still closed).
You could also participate in the video monitoring project led by Fergus Chadwick in the UK:
https://www.dropbox.com/s/6vk2j614y3rempa/ThePollinatorsofIvyMonitoringProjectHowTo3.0.docx?dl=0
Thanks to Connie for observing the flowering and sending the images!