It is not just the matter of having the same first four letters. There is much more that is shared by violins and violets.
The confusion and the fun begin with the fact that the viola, in addition to being a stringed instrument, is a genus of flowering plant as well. Differing roots somehow ultimately led to the same word for both. While that is a pleasing and possibly confusing coincidence, it is usually not difficult to know which of the two is meant in conversation or writing due to the clues provided by the context. Thus far, it is fairly clear — in English, at least. Then, it appears that the lovely viola branches off in various languages to arrive at diminutives (violetta in Italian; the French violette) which are the equivalent of what we know as violets.
A beautiful bunch of violets
This era in which we find ourselves possesses characteristics that I know I will not live long enough to become used to. When I mistakenly begin to believe I am making strides, I have only to see an advertisement for an “acoustic violin” (on Amazon.com, for example) to be rudely awakened and realize yet again that there are certain things to which I should not expect to become accustomed. On the other hand, as a delicious consolation, I could not have known that learning Dutch would make me privy to some of the most marvelous double entendres imaginable. With “violin” being “viool” in Dutch, and the plural of “viool” happening to be “violen” (which also means violets or pansies), one can look in any publication’s gardening section (online or in print) and find such irresistible offers as winter-proof violins, three violins for five euros, a crate of strongly-rooted violins available for the best bid, and a few more bargains to brighten up one’s day.