Was ist der Unterschied zwischen The first cherry blossoms are in bloom. Yet a lot to do before the spring. und The first cherry blossoms are in bloom. Still a lot to do before the spring. ?Du kannst auch einfach Beispielsätze geben.

The first one is unusual. It is not completely 'wrong', but looks non-standard written down. I had to look at it for a few seconds before I understood it.

When 'yet' means 'still', it's most often used with a negative verb ('I haven't finished it yet') or a question (Have you finished it yet?), at the end of a sentence.

However, you can use 'yet' like in your sentence. The word order is different though:
There's a lot to do yet, before spring.
There's a lot yet to do before spring.
There's still a lot to do before spring.

As for the difference, 'yet' is less common than 'still' here. Also, the 'yet + to +infinitive' pattern sounds a bit formal, as it's often used in a different way in more formal speech:
I'm yet to call her (=I haven't called her yet)
She's yet to sign the contract (= She hasn't signed the contract yet) etc.