Ispred kuće raste mali grm, a iza ograde je visoka živica.

Because ispred and iza normally take the genitive case in Croatian.

• kuća → kuće in the genitive singular
• ograda → ograde in the genitive singular

So:

• ispred kuće = in front of the house
• iza ograde = behind the fence

This is something you usually just learn together with the preposition: ispred + genitive, iza + genitive.

Raste means grows / is growing. With plants, Croatian often uses a verb like rasti very naturally.

So Ispred kuće raste mali grm is literally something like:

• In front of the house, a small bush grows

In natural English, you might simply say There is a small bush in front of the house, but Croatian often prefers the more concrete verb when talking about plants.

Yes, it could.

• Iza ograde je visoka živica = Behind the fence there is a tall hedge.
• Iza ograde raste visoka živica = Behind the fence a tall hedge grows / is growing.

The difference is mainly in focus:

• je just states that the hedge is there
• raste emphasizes that it is a plant growing there

Both are possible, but je is a simple neutral description of location.

A often means and, but with a slight sense of contrast, shift, or comparison.

Here it connects two related facts:

• in front of the house: a small bush
• behind the fence: a tall hedge

So a feels a bit like:

• and meanwhile
• while
• whereas

Using i would sound more like simple addition. A is very natural when you are setting one picture against another.

Croatian word order is quite flexible. The sentence starts with the location because that is the information being set up first.

• Ispred kuće raste mali grm = In front of the house, a small bush grows.
• Mali grm raste ispred kuće = A small bush grows in front of the house.

Both are grammatical. The first version sounds more descriptive and scene-setting. Croatian often puts the location first when describing what is where.

Because adjectives must agree with the noun in gender, number, and case.

• grm is masculine singular → mali grm
• živica is feminine singular → visoka živica

Both nouns are in the nominative singular here because they are the subjects of their clauses.

They are not the same kind of plant word.

• grm = bush / shrub
• živica = hedge

A grm is usually a single bush.
A živica is usually a line of bushes or shrubs, often planted as a boundary and often trimmed.

So the sentence contrasts:

• a small single bush
• a tall hedge

Croatian does not need a dummy subject like English there.

English says:

• There is a tall hedge behind the fence

Croatian simply says:

• Iza ograde je visoka živica

Literally, this is closer to:

• Behind the fence is a tall hedge

So there is no separate word corresponding to English there in this kind of sentence.

Because Croatian has no articles.

So:

• kuća can mean a house or the house
• grm can mean a bush or the bush
• živica can mean a hedge or the hedge

The exact meaning is understood from context. That is why Croatian learners of English must learn articles, but English learners of Croatian must learn to do without them.

They are similar, but not always identical.

• ispred + genitive = in front of
• pred + instrumental = in front of / before

For physical location, especially something outside and before the front side of a building, ispred kuće is very common and neutral.

• ispred kuće = in front of the house

Pred kućom is also possible, but ispred kuće is often the more straightforward choice in this kind of spatial description.

These sounds are important in Croatian.

• ž in živica sounds like the s in measure
• ć in kuće is a soft sound, somewhat like a very soft ch, but not exactly the English ch
• c in živica is pronounced ts, like the end of cats

So roughly:

• živica ≈ zhee-vee-tsa
• kuće ≈ koo-cheh, but with a softer ch sound than in English

Even if your pronunciation is not perfect at first, it is good to notice that c = ts and ž is not a regular English z.