The answer to this question depends a little on whether you're starting from scratch or dealing with established domains. Here are some factors to consider:
1) Google has greatly reduced the impact of exact match domains (EMDs) there the search phrase is in the domain.
2) Google has greatly increased the impact of having a solidly established brand.
3) Operating multiple websites for one flower shop is a bad idea 90% of the time. It creates confusion as Google is looking for one domain to match one business. If there are two similar sites Google has less confidence in the answer and will give preference to businesses with clearer confidence signals.
4) Google rarely ranks two sites from the same company in the same results page, so you're just competing against yourself with multiple sites.
5) Multiple sites confuse your customers and weaken your branding.
6) Domain authority and trust are major ranking factors, and both rely somewhat on history. There are some potential benefits from changing your domain name, but you really need to consider the potential impact from switching from an established domain (3, 5, 10 years?) to a new domain with no history.
7) If you are consolidating your domains make sure to use a 301 redirect on all the secondary domains pointing to the primary domain. Never, ever, serve up the same site under multiple domains.
Hope that gives you a bit to reflect on