I love Project BudBurst and had my own elementary education students observe seasonal events in dogwood trees for several semesters, but never got around to submitting their data on the BudBurst website. So I think I can suggest several ways for BudBurst to encourage more "follow through".
(The drawing shown is copyright-free and comes from USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 2: 664.)
Step 1: Are You Sure That's a Dogwood?
Step 2: Is It Blooming Yet?
I think teachers need clear images of what to look for and need to be able to verify that their students are ready to pinpoint the date of "First Flowers".
(This image is not copyrighted and is from Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database / USDA NRCS. 1995. Northeast wetland flora: Field office guide to plant species. Northeast National Technical Center, Chester.)
Step 3: Can We Schedule a Wake-up Call?
(This image is not copyrighted and is from W.D. Brush @ USDA-NRCS PLANTS Database.)