geom_GeomLabel() has yet to be implemented in plotly.

library(ggplot2)
library(plotly)

end_points <- iris %>% 
  group_by(Species) %>% 
  filter(Sepal.Length == max(Sepal.Length))

# Create the plot
g = ggplot(iris, aes(x = Sepal.Length, y = Sepal.Width, color = Species, group = Species)) +
  geom_line() + 
  geom_label(data = end_points, aes(label = Sepal.Length), color = "white", vjust = -0.5) +
  theme_minimal()

ggplotly(g)

Result:
Warning message:
In geom2trace.default(dots[[1L]][[1L]], dots[[2L]][[1L]], dots[[3L]][[1L]]) :
geom_GeomLabel() has yet to be implemented in plotly.
If you'd like to see this geom implemented,
Please open an issue with your example code at
https://github.com/ropensci/plotly/issues

I would like to see this implemented. Thanks for making a great package available in R!

Start by running the provided R example and tracing the geom2trace.default warning for geom_GeomLabel(). Use the ggplot2 geom_label example as the behavior reference; done means ggplotly renders the labels without reporting that GeomLabel is unimplemented.