Verb-ing words can function as nouns, adjective and verbs.
Growing plants is my hobby.
Growing plants in your back yard need more care.
I am growing aromatic plants in my garden.
In the first sentence, “growing” is a noun, in the second, it’s an adjective, and in the last sentence together with “am”, it is a verb in present continuous tense.
Now consider the following 2 sentences
1.) Growing plants in your back yard need more care.
2.) Marketing baby products in the internet world requires a cohesive message to be spread through traditional print and social media.
In 1st sentence, “growing” is the adjective that presents a characteristic of the “plants”. In 2nd sentence, “marketing”, the verb-ing word acts as a noun and forms a big noun phrase “Marketing baby products in the internet world” that is the subject of the sentence.
Now my question is why the verb+ing modifier is different in the two sentences when they have the same structure of Verb+ing modifier+ noun+ prepositional phrase. How i can distinguish between two ? Is there any rule?