Ružmarin treba sunčevu svjetlost, a metvica voli polusjenu.

Because both trebati and voljeti take a direct object here, and that object goes in the accusative case.

• dictionary form: sunčeva svjetlost → accusative: sunčevu svjetlost
• dictionary form: polusjena → accusative: polusjenu

So:

• Ružmarin treba sunčevu svjetlost = rosemary needs sunlight
• metvica voli polusjenu = mint likes partial shade

For feminine nouns, the accusative singular often changes -a to -u, and adjectives must match that too.

Here treba means needs.

The verb is trebati. In this sentence:

• Ružmarin treba sunčevu svjetlost = rosemary needs sunlight

A very useful thing to know is that trebati can be used in more than one way in Croatian. For example, it can also mean should / need to in other structures. But in this sentence it is the simple lexical meaning to need something.

A often means something like and, while, or whereas, depending on context.

In this sentence, it is best understood as a contrastive connector:

• Ružmarin treba sunčevu svjetlost, a metvica voli polusjenu.
• Rosemary needs sunlight, while mint likes partial shade.

So this a is not exactly the same as simple English and. It sets up a contrast between the two plants.

This is a very common question.

• i = plain and
• a = and / while / whereas, often with contrast or a shift of topic

Compare:

• Ružmarin i metvica rastu u vrtu. = Rosemary and mint grow in the garden.
• Ružmarin treba sunčevu svjetlost, a metvica voli polusjenu. = Rosemary needs sunlight, while mint likes partial shade.

So a is the more natural choice here because the sentence compares two different needs.

Sunčevu is a possessive adjective built from sunce = sun.

• sunce = the sun
• sunčev = the sun’s / solar, in a natural everyday sense

So:

• sunčeva svjetlost literally means the sun’s light
• in natural English, that is simply sunlight

Croatian often uses possessive adjectives like this very naturally.

Yes, svjetlost is feminine.

A useful rule is that many Croatian nouns ending in -ost are feminine, for example:

• radost = joy
• mladost = youth
• svjetlost = light

Its nominative singular is svjetlost, and in the accusative singular it stays svjetlost. That is normal for many feminine nouns ending in a consonant.

So in sunčevu svjetlost:

• sunčevu changes to match accusative feminine singular
• svjetlost stays the same in form

Polusjena literally means half-shade or partial shade.

It is made from:

• polu- = semi-, half-
• sjena = shade, shadow

So polusjena is the kind of light condition where a plant gets some sun but not full direct sun all day.

The verb voljeti literally means to love, but in everyday Croatian it is also used for to like, especially with things, activities, foods, and conditions.

So:

• metvica voli polusjenu literally = mint loves partial shade
• natural English = mint likes partial shade / prefers partial shade

English usually avoids saying that a plant loves something unless we are being figurative, but Croatian uses voljeti very naturally here.

Not completely. Croatian word order is more flexible than English because case endings show grammatical roles.

The given sentence is the most neutral and natural:

• Ružmarin treba sunčevu svjetlost, a metvica voli polusjenu.

But other orders are possible for emphasis, for example:

• Sunčevu svjetlost treba ružmarin, a polusjenu voli metvica.

That sounds more marked and emphasizes the conditions rather than the plants.

So learners should usually stick to the original order unless they have a reason to emphasize something.

Croatian has no articles like English the and a/an.

So:

• Ružmarin can mean rosemary or the rosemary
• sunčevu svjetlost can mean sunlight or the sunlight, depending on context
• metvica can mean mint or the mint

Croatian relies on context, word order, and general meaning instead of articles.

A few pronunciation points that often help English speakers:

• Ružmarin: the ž sounds like the s in measure
• svjetlost: svj can feel tricky; say it roughly like svye-
• metvica: the c is pronounced ts
• polusjenu: the j is like English y
• č in sunčevu is like ch in church

Very rough English-style guides:

• Ružmarin ≈ ROOZH-ma-rin
• svjetlost ≈ SVYET-lost
• metvica ≈ MET-vee-tsa
• polusjenu ≈ po-loo-SHYE-noo

These are only approximations, but they can help at first.

Yes, you can, and it would be understandable. Ružmarin treba sunce means rosemary needs sun.

But sunčevu svjetlost is a bit more precise and natural in a gardening context because it refers specifically to sunlight rather than the sun as an object.

So both are possible, but:

• treba sunce = needs sun
• treba sunčevu svjetlost = needs sunlight

The second one sounds slightly more specific and descriptive.

Yes, in this sentence both verbs take a direct object in the accusative:

• trebati
  • accusative
• voljeti
  • accusative

That is why you get:

• sunčevu svjetlost
• polusjenu

This is a good pattern to remember, because voljeti very commonly takes accusative objects:

• Volim kavu. = I like coffee.
• Voli glazbu. = He/She likes music.

And trebati can also take an accusative noun when it means need in this concrete sense:

• Trebam pomoć. = I need help.
• Biljka treba vodu. = The plant needs water.