Der Gärtner sagt, jede Rose brauche im Sommer mehr Wasser als im April.

brauche is Konjunktiv I of brauchen in the 3rd person singular. German often uses Konjunktiv I for indirect/reported speech, especially after verbs like sagt, meint, erklärt, etc.

So:

• jede Rose braucht ... = normal statement
• jede Rose brauche ... = reported statement: this is what the gardener says

It helps show that the speaker is reporting someone else’s claim, not necessarily stating it directly as a fact.

Yes. In everyday spoken German, many people would use braucht instead of brauche.

The difference is mainly one of style and clarity:

• brauche = more formal, more clearly marks reported speech
• braucht = common in everyday language, more neutral/colloquial

So the original sentence sounds a bit more careful or written.

German can report what someone says in two common ways:

1. without dass
   Der Gärtner sagt, jede Rose brauche ...

2. with dass
   Der Gärtner sagt, dass jede Rose im Sommer mehr Wasser brauche ...

Both are possible. Without dass, the sentence is a little more compact. With dass, the clause is more explicitly introduced as a subordinate clause.

Yes.

Without dass:

• Der Gärtner sagt, jede Rose brauche im Sommer mehr Wasser als im April.

With dass:

• Der Gärtner sagt, dass jede Rose im Sommer mehr Wasser brauche als im April.

The main difference is that after dass, the clause uses normal subordinate-clause word order, so the verb brauche moves to the end.

jede Rose is the subject of brauche, so it is in the nominative case.

Rose is a feminine noun, so jeder/jede/jedes must agree with it:

• masculine nominative: jeder
• feminine nominative: jede
• neuter nominative: jedes

So:

• jede Rose = feminine nominative singular

Because jede means each or every, and in German that is normally followed by a singular noun:

• jede Rose = each/every rose

If you wanted a plural idea like all roses, you would say:

• alle Rosen

So jede Rose and alle Rosen are different structures.

im is a contraction of in dem.

So:

• im Sommer = in dem Sommer
• im April = in dem April

In time expressions like seasons and months, German often uses in + dative, and in dem usually contracts to im.

Because they are all nouns, and all German nouns are capitalized.

That includes:

• common nouns: Gärtner, Rose, Wasser
• names of months: April
• seasons used as nouns: Sommer

This is a basic rule of German spelling.

German uses als after a comparative:

• mehr Wasser als im April
• größer als
• schneller als

German uses wie for equality, not comparison of more/less:

• so viel Wasser wie im April = as much water as in April

So:

• mehr ... als ... = more ... than ...
• so viel ... wie ... = as much ... as ...

Because Wasser is usually an uncountable noun, like water in English.

So German says:

• mehr Wasser = more water

not a plural form meaning separate countable items.

This works the same way as in English:

• more water
• not more waters in normal usage

Yes. It is an elliptical comparison, meaning some repeated words are left out because they are understood from the context.

The sentence means something like:

• each rose needs more water in summer than it does in April

German often leaves out the repeated part when it is obvious. That is why als im April sounds natural and complete here.

A direct version would be:

Der Gärtner sagt: Jede Rose braucht im Sommer mehr Wasser als im April.

Here, braucht is the normal indicative form because we are presenting the statement directly.

The original sentence uses brauche to report the content indirectly.