Oops, it doesn't look like 'plants day' is a national day..

Other days

hoodie

Hoodie Day
ruby

Ruby Day
lisp

Lisp Day
nail polish

Nail Polish Day
lash

Lash Day
youth

Youth Day
get funky

Get Funky Day
tell a fairytale

Tell A Fairytale Day
slime

Slime Day
promposal

Promposal Day