Enter for?

I've encountered two sentences below in a very old English textbook:
"Nearly everybody enters for ‘The Nicest Garden Competition’ each year, but Joe wins every time."
"Every year I enter for the garden competition too, and I always win a little prize for the worst garden in the town! "

However, the comtemporary dictionary says 'enter' does not need to be followed by 'for' to mean 'take part in', so are these sentences even correct nowadays?
But if the preposition 'for' is crossed out, would the sentences be misunderstood as ‘enter into the next round of the competition'?

Thanks in advance!