Learn Hardcore Polish: Latem w parku szybko rosną kwiaty. - In the summer flowers grow quickly in the park.

In Polish, time expressions are often formed with the instrumental case without a preposition:
- Latem – in (the) summer
- Zimą – in (the) winter
- Wiosną – in (the) spring
You can also say:
- W lecie – literally “in the summer”, using the preposition w
  - locative case.
- Latem and w lecie are both correct and normal. Latem is a little more compact and quite common in spoken and written Polish.

W lato is not correct in standard Polish. With w meaning “in”, you need the locative case: w lecie, not w lato.

What case is w parku, and why is it parku and not park?

W parku is preposition + locative case.

The preposition w (in) takes:
- Locative when it describes location (where?):
  - w parku – in the park
  - w domu – at home
  - w sklepie – in the shop
- Accusative when it describes movement into something (where to?):
  - w park – into the park (rare; often do parku is used instead)

Here, we are talking about where the flowers grow, not movement, so we use locative:

park (nominative)
w parku (locative, with w)

So parku appears because the noun must be in the locative case after w in this “location” meaning.

What is the subject of the sentence? It doesn’t come at the beginning, so how do I know?

The subject is kwiaty (flowers).

Polish word order is relatively flexible, and the subject does not have to be at the beginning. You recognize the subject mainly by:

Case – the subject is normally in the nominative case.
- kwiaty is nominative plural (also accusative plural, but here it functions as nominative).
Verb agreement – the verb rosną is 3rd person plural, matching kwiaty.

So even though the sentence starts with Latem w parku szybko, grammatically the subject is at the end:

Latem w parku szybko rosną kwiaty.
Literally: In summer, in the park, quickly grow flowers.

That word order is perfectly natural in Polish.

Why is it kwiaty and not something like kwiaci?

Kwiaty is the correct plural form of kwiat (flower).

Polish masculine nouns have different patterns depending on whether they’re masculine personal (groups of people that include at least one male) or non-masculine-personal (objects, animals, abstract things, etc.).

kwiat is masculine inanimate, so its nominative plural is kwiaty.
The -i / -y alternation you may know (like nauczyciel → nauczyciele) belongs to masculine personal plural forms.

Some examples:

chłopak → chłopacy/chłopaki (colloquial), mężczyzna → mężczyźni (masculine personal)
stół → stoły (table → tables, inanimate)
kwiat → kwiaty (flower → flowers, inanimate)

So kwiaci would be wrong here; kwiaty is the correct form.

What tense and person is rosną, and why isn’t it rosnąć or rosnął?

Rosną is the 3rd person plural, present tense form of the verb rosnąć (to grow).

rosną = (they) grow / are growing
rosnąć is the infinitive (to grow). You can’t use the infinitive as the main verb like in English “Flowers to grow”. You need a conjugated form.
rosnął is 3rd person singular, past tense, masculine (he/it grew). That doesn’t fit our subject kwiaty (plural).

Since the subject kwiaty is plural, the verb also has to be plural:

kwiaty rosną – the flowers grow / are growing

Why is it szybko and not szybka or szybkie?

Szybko is an adverb – it describes how the flowers grow: “quickly / fast.”

szybki / szybka / szybkie are adjectives, used with nouns:
- szybki samochód – a fast car
- szybka odpowiedź – a quick answer
- szybkie kwiaty – (odd, but grammatically) fast flowers
szybko is the adverb:
- rosną szybko – they grow quickly
- biegnę szybko – I run fast

So in this sentence we need an adverb describing the verb rosną, so we use szybko, not an adjective.

Can the word order change? For example, can I say Kwiaty szybko rosną w parku latem?

Yes. Polish allows quite flexible word order. These are all grammatically correct:

Latem w parku szybko rosną kwiaty.
Kwiaty szybko rosną w parku latem.
Szybko rosną kwiaty latem w parku.
W parku latem kwiaty szybko rosną.

The basic meaning stays the same, but the emphasis changes slightly.

Starting with Latem w parku… puts focus on the setting (time and place).
Starting with Kwiaty… puts more emphasis on the flowers.
Putting szybko right before rosną strongly ties “quickly” to the action of growing.

In everyday speech, something like Latem kwiaty szybko rosną w parku or Latem w parku kwiaty szybko rosną would sound very natural.

Is Latem obligatory? What happens if I remove latem or w parku?

Both Latem and w parku are optional modifiers.

Without Latem:
- W parku szybko rosną kwiaty. – (In the park, flowers grow quickly.)
Without w parku:
- Latem szybko rosną kwiaty. – (In summer, flowers grow quickly.)
Basic core:
- Kwiaty szybko rosną. – Flowers grow quickly.

They just add extra information:

Latem – when? (in summer)
w parku – where? (in the park)

Grammatically the sentence is fine with or without them.

Why don’t we need any articles like “the” or “a” for kwiaty and parku?

Polish has no articles (no equivalent of English a / an / the).

kwiaty can mean “flowers” / “the flowers” / “some flowers”, depending on context.
w parku can mean “in a park” or “in the park”, again depending on context.

The specificity is understood from:

context (what has already been mentioned),
word order and emphasis,
sometimes additional words:
- te kwiaty – these/the flowers
- jakieś kwiaty – some (unspecified) flowers

So Latem w parku szybko rosną kwiaty can be translated naturally as:

In summer, flowers grow quickly in the park.
or
In summer, the flowers grow quickly in the park.

Both are valid translations.

What aspect is rosną (imperfective or perfective), and why is that used here?

Rosną comes from rosnąć, which is imperfective.

rosnąć – to grow (imperfective; process, repeated/habitual actions)
perfective partners (depending on nuance) include urosnąć, wyrosnąć – to grow (up), to have grown, etc.

In the sentence, we are talking about a general, repeated situation:

Every summer, in the park, flowers grow quickly.

For general truths, habits, and ongoing processes, Polish uses imperfective in the present:

Latem w parku szybko rosną kwiaty. – In summer, flowers grow quickly in the park.

A perfective like urosną would imply a completed result (they will have grown), and would usually appear with future or past time references, not for a generic statement.

Can I say W lecie w parku szybko rosną kwiaty instead of Latem w parku szybko rosną kwiaty? Is there any difference?

Yes, you can say W lecie w parku szybko rosną kwiaty. It is grammatically correct and natural.

Differences:

Latem – shorter, slightly more neutral and very common.
W lecie – a bit more explicit, but also common.

They both mean “in (the) summer” and are interchangeable in most contexts. In many sentences you will hear Latem simply because it is more compact.

Why is it w parku and not na parku? What’s the difference between w and na in this kind of sentence?

Both w and na can translate as “in / on / at”, but they collocate with different nouns.

For park, the normal, idiomatic preposition is w:
- w parku – in the park

Using na parku would sound wrong to a native speaker in this sense.

General tendencies (not absolute rules):

w is often used for enclosed or defined spaces:
- w domu – at home
- w sklepie – in the shop
- w szkole – at school
- w parku – in the park
na is used with many open areas, surfaces, events, institutions, etc.:
- na ulicy – on the street
- na plaży – on the beach
- na koncertach – at concerts
- na uczelni – at university

You just have to learn the typical combinations. For park, the standard one is w parku.

Could I use kwiatki instead of kwiaty? Does it change the meaning?

Yes, you can say:

Latem w parku szybko rosną kwiatki.

Kwiatki is the diminutive of kwiaty:

kwiaty – flowers (neutral)
kwiatki – little flowers / cute flowers, often more informal or affectionate

The grammar (case, number, position in the sentence) remains the same; only the tone changes slightly to something more emotional, informal, or “cute.”