Why is it "de tulipes pourpres" instead of "des tulipes pourpres"

Question

Earlier in the sentence, I understand why it's "de délicates pâquerettes blanches" instead of "des" (because the adj precedes the noun and that causes the plural partitive/indefinite article to change from des to de) but I don't understand why that's been done to the tulips too.

Accepted Answer

The phrase is "éntrecoupé de" -- interspersed with.Pâquerettes blanches -- white daisies
You don't need the definite article here because you're not talking about specific daisies. It's just as in English where you also say "a bed of white daisies" and not "a bed of the white daisies". And for just the same reason you have "de tulipes" and not "des tulipes". 
The option is given to invert the word order and have "délicates pâquerettes blanches" instead. But that just adds another reason to have "de" instead of "des".

Answer

Hi Laura,Not sure, but on entering the show the air was filled with various flower scents some of which was "of" Tulips  --> "de tulipes pourpres".This is what occurs to me but just my guess.Jim