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

Other days

ruby

Ruby Day
pick me

Pick Me Day
tulip

Tulip Day
my little pony

My Little Pony Day
donate your hair

Donate Your Hair Day
pumpkin

Pumpkin Day
one

One Day
healing

Healing Day
azonto is acceptable

Azonto Is Acceptable Day
singles

Singles Day