Learn Hardcore German: Im Herbst ist die Landschaft bunt, und der Geruch von nassem Laub liegt in der Luft. - In autumn the landscape is colorful, and the smell of wet leaves is in the air.

The preposition in here is used for a time expression (“in autumn”), and it takes the dative case.
Herbst is masculine:
- nominative: der Herbst
- dative: dem Herbst
So in dem Herbst → im Herbst.

In Herbst is ungrammatical in this meaning.
You could also say im Frühling, im Sommer, im Winter.

Could I also say Die Landschaft ist im Herbst bunt? Is that different from Im Herbst ist die Landschaft bunt?

Both sentences are correct and mean the same thing.

Die Landschaft ist im Herbst bunt.
Neutral word order: subject – verb – rest.
Im Herbst ist die Landschaft bunt.
The time phrase Im Herbst is moved to the first position for emphasis (“In autumn, the landscape is colourful”).

German main clauses must keep the finite verb in second position (so‑called “verb-second rule”):

Im Herbst (1st element)
ist (2nd element = verb)
die Landschaft bunt (rest)

Changing what comes first usually changes only the emphasis, not the basic meaning.

Why is the verb ist in second position and not directly after the subject like in English?

German main clauses follow the “verb-second” (V2) rule:

The conjugated verb is always the second element in a main clause.
The first element can be the subject, or a time phrase, or a place phrase, etc.

In your sentence:

First clause: Im Herbst (1st) – ist (2nd) – die Landschaft bunt (rest).
If the subject comes first, it looks like English:
- Die Landschaft (1st) – ist (2nd) – im Herbst bunt (rest).

So it’s not “subject–verb–object” like English, but “(any one element)–verb–rest”.

Why is bunt at the end and not die bunte Landschaft like in English “the colourful landscape”?

Here bunt is a predicate adjective, not part of the noun phrase.

Die bunte Landschaft = attributive adjective:
- The adjective is part of the noun phrase and stands before the noun.
- It needs an ending: bunte.
Die Landschaft ist bunt = predicate adjective:
- The adjective describes the state of the subject via a verb like sein (to be), werden (to become), bleiben (to remain).
- It follows the verb and appears in its basic form (no ending).

In the sentence, bunt is like English “is colourful”, not like “the colourful landscape”.

Why does Landschaft have die, but Herbst and Laub have no article here?

Three different reasons:

Die Landschaft
- Landschaft is a specific noun here (the landscape we see), so it gets a definite article.
- It is feminine: die Landschaft (nominative singular, subject).
Im Herbst
- The article is there, just hidden in the contraction:
  in + dem Herbst → im Herbst.
nasses Laub / nassem Laub
- Laub (foliage) is a mass noun / uncountable in German.
- Mass nouns often have no article when speaking generally:
  - nasses Laub = “wet leaves” in general, not some specific pile of leaves.

So:

die Landschaft = “the landscape” (specific thing, visible subject)
im Herbst = “in the autumn” (with article, contracted)
nasses Laub = “wet leaves” (general substance, no article)

Why do we write a comma before und: …, und der Geruch …? Is that obligatory?

You have two main clauses joined by und:

Im Herbst ist die Landschaft bunt
der Geruch von nassem Laub liegt in der Luft

In German, a comma can be used before und when it joins two main clauses. It is:

optional in many simple cases,
but strongly recommended (and usually used) when:
- the clauses have different subjects (here: die Landschaft vs. der Geruch), or
- they are longer or more complex.

So:

With comma: Im Herbst ist die Landschaft bunt, und der Geruch …
→ very natural and clear.
Without comma would be possible in modern spelling, but less clear and less common in formal writing.

Why is it der Geruch von nassem Laub and not der Geruch des nassen Laubs?

Both are grammatically correct; the difference is style and nuance.

der Geruch von nassem Laub
- Uses von + dative: von nassem Laub.
- Very common, especially in spoken and everyday written German.
- Feels neutral and natural.
der Geruch des nassen Laubs
- Uses genitive: des nassen Laubs.
- Sounds more formal, literary, or poetic.
- Emphasizes a bit more that the smell belongs to the wet leaves.

In everyday speech and most writing, von nassem Laub is more typical.

How is nassem Laub formed? Why nassem and not nasses or nassen?

Break it down:

Preposition von always takes the dative case.
Laub is neuter:
- nominative: das Laub
- dative: dem Laub
There is no article in the phrase (von nassem Laub, not von dem nassen Laub).

If there is no article, the adjective takes strong endings.
For dative neuter singular (strong), the ending is -em:

nassem Laub

Compare:

nasses Laub – nominative/accusative neuter, no article (“wet leaves” as subject or object)
mit nassem Laub – dative after mit
von nassem Laub – dative after von

Why do we say der Geruch von nassem Laub liegt in der Luft? Why use liegt with a smell?

This is a common idiom in German.

liegen can mean “to lie, to be lying (somewhere)” but also more generally:
- “to be present / to be in the air / to hang around in the atmosphere”.

Expressions like:

Der Duft von Kaffee liegt in der Luft.
“The smell of coffee is in the air.”
Spannung liegt in der Luft.
“There is tension in the air.”

So liegt in der Luft here means roughly “is present in the air / hangs in the air”, and it’s very natural to use this with smells or abstract things like Spannung (tension), Erwartung (anticipation), etc.

Why is it in der Luft (dative) and not in die Luft (accusative)?

With in, German distinguishes between:

Dative for a location (where something is)
Accusative for a direction / movement (where something is going)

In this sentence, the smell is located in the air, not moving into the air:

in der Luft – dative → location (“in the air”)
in die Luft – accusative → direction (“into the air”)

Examples:

Der Ball ist in der Luft. – The ball is in the air. (no movement, dative)
Er wirft den Ball in die Luft. – He throws the ball into the air. (movement, accusative)

So liegt in der Luft must use dative.

Why is Laub singular in German when the English translation uses “leaves” (plural)?

Laub is a collective noun in German.

It refers to leaves as a mass (like “foliage” in English).
It is grammatically singular: das Laub.
To talk about individual leaves, German uses Blatt / Blätter:
- ein Blatt = one leaf
- Blätter = leaves

So:

nasses Laub = wet foliage / wet leaves (as a mass)
nasse Blätter = wet leaves (countable, plural)

In this sentence, Laub emphasizes the general carpet of leaves / foliage, not individual leaves.

Why can’t we just say Im Herbst die Landschaft bunt, und der Geruch … in der Luft without ist and liegt, like in English poetry?

In standard German, the finite verb cannot be omitted from a main clause.

German grammar requires a verb like sein, liegen, stehen, etc.
Leaving out ist or liegt would sound ungrammatical in normal prose.

English allows structures like:

“In autumn, the landscape colourful, the smell of wet leaves in the air.”

This is poetic/elliptical English.
German can also be poetic and elliptical, but dropping ist and liegt in exactly this way would be very unusual and generally considered incorrect in standard language.

Could we also say Im Herbst wird die Landschaft bunt? What’s the difference to ist bunt?

Yes, both are correct, but the aspect is different:

Im Herbst ist die Landschaft bunt.
- Focus on the state: during autumn, the landscape is colourful.
- Describes a typical situation.
Im Herbst wird die Landschaft bunt.
- Uses werden (“to become”), focusing on the process / change:
- “In autumn, the landscape becomes colourful.”
- Highlights that the colours develop in autumn.

So:

ist bunt = state
wird bunt = change into that state

Both are perfectly natural; context decides which fits better.