Mám nejen stínomilné rostliny, ale i světlomilné rostliny.

It means not only ... but also ....

So:

• nejen stínomilné rostliny = not only shade-loving plants
• ale i světlomilné rostliny = but also light-loving plants

This is a very common Czech pairing. You will also often see:

• nejen ..., ale také ...

which means the same thing.

Mám is the 1st person singular present form of mít (to have).

So:

• mám = I have

In this sentence, it simply shows possession: I have ...

Because rostliny is the direct object of mám, so it is in the accusative case.

The base noun is:

• rostlina = plant

Its plural forms include:

• rostliny = nominative plural
• rostliny = accusative plural

For this feminine noun, the nominative plural and accusative plural happen to look the same, so the form stays rostliny.

Because adjectives in Czech must agree with the noun they describe in:

• gender
• number
• case

Here the noun is:

• rostliny = feminine plural, accusative

So the adjectives must match that:

• stínomilné rostliny
• světlomilné rostliny

That -é ending is the correct agreeing form for these adjectives with rostliny here.

They are adjectives used especially for plants.

• stínomilný / stínomilné = shade-loving, shade-preferring
• světlomilný / světlomilné = light-loving, light-preferring

They are compounds built from:

• stín = shade
• světlo = light
• -milný = loving, fond of

So literally they mean something like shade-loving and light-loving.

Not exactly.

• světlomilné means light-loving or preferring a lot of light
• sun-loving would more specifically suggest direct sun

So světlomilné can overlap with sun-loving, but it is a bit broader. In plant language, it usually means the plant likes bright conditions.

Because nejen usually goes right before the part it is focusing on.

Here it focuses on the first item in the contrast:

• nejen stínomilné rostliny
• ale i světlomilné rostliny

So the sentence is structured very clearly as:

I have not only X, but also Y.

If you move nejen, the emphasis can shift, or the sentence can start to sound less natural.

Yes. Both are correct.

So you can say:

• Mám nejen stínomilné rostliny, ale i světlomilné rostliny.
• Mám nejen stínomilné rostliny, ale také světlomilné rostliny.

Both mean I have not only shade-loving plants, but also light-loving plants.

A small nuance:

• ale i can sound a bit tighter or lighter
• ale také can sound slightly fuller or more explicit

But in most contexts, they are interchangeable.

No. You can omit it if the meaning is clear.

For example:

• Mám nejen stínomilné rostliny, ale i světlomilné.

That is perfectly natural, because rostliny is easy to understand from the first half.

Repeating rostliny in both halves makes the sentence more balanced and explicit.

Because Czech does not use articles like English the, a, or an.

So rostliny can mean:

• plants
• the plants
• some plants

The exact meaning depends on context.

That is very normal in Czech, and learners from English often notice it immediately.

A rough English-friendly guide:

• stínomilné ≈ stee-no-mil-nay
• světlomilné ≈ svye-tlo-mil-nay

A few useful points:

• í is a long ee sound
• é is a long ay/eh-type vowel
• ě often creates a y sound after the consonant, so svě sounds roughly like svye

You do not need a perfect English spelling approximation; the main thing is to notice that Czech vowels are pronounced clearly and consistently.

Yes, it is natural, especially if you are talking about gardening or plant care.

The adjectives stínomilný and světlomilný are a little more specific than very basic everyday vocabulary, but they are completely normal in contexts about plants, biology, or gardening.

A more casual paraphrase might be something like:

• Mám rostliny do stínu i na světlo.

But your original sentence is correct and natural.

Yes, Czech word order is flexible, but this version is a very clear and standard one.

This sentence:

• Mám nejen stínomilné rostliny, ale i světlomilné rostliny.

works well because it keeps the paired structure very obvious.

Czech often moves words around for emphasis, but with a pattern like nejen ..., ale i ..., learners should usually keep the structure stable until they are comfortable with it.