What you were seeing before was an incomplete picture. Above is how it originally looked.

Flowers are an important part of a plant and are in fact the way they reproduce themselves. If we could not detect flowers (because they are not green), we could not begin to know how plants reproduced! We could probably not see plant roots either, which would hinder us from learning how plants get nutrition. We couldn't even see soil, so we wouldn't know what the plants were getting their nutrition from!

There would be large gaps in our knowledge of plants and how they work. This is similar to our problems in astronomy.