У дома растёт высокий клён, и осенью под ним много листьев.

У дома means by the house / near the house.

In Russian, у + genitive is a very common way to say that something is located near something else:

• у дома = by the house
• у школы = by the school
• у реки = by the river

Here дома is the genitive singular of дом.

You could also say возле дома or около дома, and those also mean near the house. But у дома is short, common, and very natural.

Because the preposition у requires the genitive.

So:

• дом = nominative
• дома = genitive

This is something you usually just learn together with the preposition:

• у + genitive
• под + instrumental for location
• в/на + prepositional for location

So у дома is not optional grammar; it is the form Russian requires after у.

Растёт is the 3rd person singular form of расти = to grow.

It is singular because the subject is высокий клён = a tall maple tree, which is singular.

So:

• клён растёт = the maple grows / is growing
• клёны растут = the maple trees grow / are growing

In this sentence, растёт can sound a bit like English there is a tall maple growing by the house, not only the maple is growing in the literal process sense.

Because both words are in the nominative singular masculine, and the adjective agrees with the noun.

• клён is masculine singular
• so the adjective must also be masculine singular: высокий

Compare:

• высокий клён = a tall maple
• высокая берёза = a tall birch
• высокое дерево = a tall tree
• высокие деревья = tall trees

Russian adjectives always match the noun in gender, number, and case.

Клён means maple or maple tree.

The ё is important here:

• клён is pronounced roughly klyon
• the stress is on ё, and ё is always stressed

In printed Russian, ё is sometimes written as е, so you may occasionally see клен, but it still means клён and is pronounced the same way if the word is known.

Because осенью is the form used to mean in autumn / in the fall.

This is the instrumental case of осень:

• осень = autumn (dictionary form)
• осенью = in autumn

Russian often uses the instrumental case for seasons when talking about time:

• весной = in spring
• летом = in summer
• осенью = in autumn
• зимой = in winter

So this is a very common pattern that learners usually memorize as whole expressions.

Because под here means under, and for location it takes the instrumental case.

The pronoun refers back to клён:

• клён = maple tree
• под ним = under it / under him grammatically, but in English here we say under it

The basic pronoun is он, but after a preposition Russian often adds н-:

• с ним = with him/it
• под ним = under him/it
• перед ним = in front of him/it

So под ним literally means under it, referring to the tree.

Russian does not have a separate everyday personal pronoun for it the way English does.

Instead, nouns have grammatical gender, and pronouns follow that gender:

• masculine noun → он / ним
• feminine noun → она / ней
• neuter noun → оно / ним

Since клён is masculine, Russian uses masculine pronoun forms for it:

• клён ... под ним = the maple ... under it

So although ним can mean him, in this sentence it naturally means it because it refers to a tree.

Because Russian very often omits есть in present-tense sentences of existence.

So:

• под ним много листьев literally = under it many leaves
• natural English = there are many leaves under it

Russian often leaves out the equivalent of there is / there are in the present tense:

• На столе книга. = There is a book on the table.
• В комнате много людей. = There are many people in the room.
• Под ним много листьев. = There are many leaves under it.

This is completely normal Russian.

Because after много Russian uses the genitive plural.

So:

• листья = nominative plural (leaves)
• листьев = genitive plural

That is why Russian says:

• много листьев = many leaves
• много книг = many books
• много домов = many houses

This is one of the most important quantity patterns in Russian:

• много + genitive plural

The dictionary form is лист = leaf or sheet, depending on context.

Its forms here are:

• singular: лист
• nominative plural: листья
• genitive plural: листьев

So in the sentence:

• много листьев = many leaves

This noun has a plural pattern learners need to get used to:

• лист → листья, not листы in this meaning

Note:

• листы does exist, but it is more often used for sheets, panels, or certain kinds of flat pieces
• for tree leaves, листья is the normal plural

Because много itself expresses quantity, and the noun after it goes into the genitive plural form.

Russian grammar does not work the same way as English here. English says:

• many leaves

Russian says:

• many + of leaves, structurally speaking

That is why the noun form changes after много.

Also, when много is the subject of a sentence, the verb is often neuter singular in past tense, for example:

• Много людей пришло. = A lot of people came.

So learners often notice that quantity expressions in Russian behave a bit differently from normal plural nouns.

Because Russian word order is flexible, and speakers often put the location or the setting first.

So:

• У дома растёт высокий клён
  = By the house there grows a tall maple / There is a tall maple by the house

This sounds natural because the sentence first tells you where, then tells you what is there.

A different word order is possible, for example:

• Высокий клён растёт у дома

This is also grammatical, but the focus feels a bit different. The original sentence is very natural if the speaker wants to set the scene first.

Because и here joins two separate clauses:

1. У дома растёт высокий клён
2. осенью под ним много листьев

Each part has its own structure and its own idea, so Russian normally puts a comma before и in this kind of compound sentence.

Very roughly:

• A, and B

That is why the comma is there.

Not necessarily.

In this sentence, растёт is better understood as grows / stands growing / is there growing. It describes the tree as being located there, not necessarily emphasizing the process at this exact moment.

So the whole first part is close to:

• There is a tall maple tree growing by the house
• or simply A tall maple tree grows by the house

Russian расти is often used this way for plants and trees when describing where they grow.

Grammatically, it most naturally refers to клён.

The nearest suitable noun is клён, and the meaning also makes sense: in autumn, there are many leaves under the tree.

If it referred to дом, the sentence would be odd, because under the house there are many leaves is not the natural idea here.

So in normal reading, ним clearly points to the maple.

It can do both, but it most naturally sounds like a descriptive statement about a place.

• У дома растёт высокий клён = by the house there is a tall maple
• осенью под ним много листьев = in autumn there are many leaves under it

So it feels like someone is describing what the place is like. Russian present tense often works well for this kind of general, ongoing description.