"Are there flowers?"
for reference, if you are bringing up a topic, it should be は (as in questioning), if you are saying something related to your money が makes more sense.
So what you will usually see is 「お金はありますか？」for questions and「お金があります」for facts about yourself as in "I have money". However you can use both が and は in both cases, it just depends of the context and how do you wanna change a topic or not.
Plants are usually considered inanimate in Japanese. There's a good discussion of the categories of animacy for Japanese on wikipedia. https://en.wikipedia.org/wiki/Animacy#Japanese
Generally, people and animals are animate, and non-living objects and plants are considered inanimate. (There are exceptions, like robots can go either way depending if you are emphasizing their animate properties or not).