One of the things I was told as a beginner beekeeper was that Spring colony inspections shouldn't commence until the Flowering Currant was in bloom - that's Ribes sanguineum for those who prefer the Latin names.
(Image from BBC Plant Finder)
Rules of Thumb
We have one of these shrubs in our garden and it's only just in flower, which would suggest it's time to open the hives for the first inspection of the season - but this particular plant is growing in a cold pocket, so always flowers later than any other in the area. This means that the 'rule' doesn't work too well for me and my bees.
