La regadera está detrás de la maceta, al lado del cactus.

Because the sentence is describing location. In Spanish, where something is located is normally expressed with estar, not ser.

• La regadera está detrás de la maceta. = it is located behind the plant pot.
• Es is usually used for identity, classification, origin, time, and other more permanent-type descriptions.

So for physical position, estar is the natural choice.

The accent mark is important because it distinguishes está from esta.

• está = is (from the verb estar)
• esta = this (feminine singular)

Examples:

• Esta maceta = this plant pot
• La regadera está... = the watering can is...

So the written accent helps show that this word is the verb form.

Detrás de is a fixed expression meaning behind.

In Spanish, many position words work as multi-word expressions and require de before the noun that follows:

• detrás de la maceta
• delante de la puerta
• encima de la mesa
• debajo de la silla

So you should learn detrás de as one unit, not just detrás by itself in this kind of sentence.

Because del is the contraction of de + el.

• de + la = de la → no contraction
• de + el = del → contraction required

So:

• detrás de la maceta
• al lado del cactus

This is a very common rule in Spanish:

• Voy al mercado = a + el
• Vengo del parque = de + el

Because the full expression is al lado de, which means next to / beside.

You usually need the whole phrase:

• al lado de la casa
• al lado del cactus

Literally, it comes from a + el lado de, but in modern Spanish you should simply learn al lado de as a set phrase.

Spanish uses articles more often than English does. In this sentence, the speaker is referring to specific objects in a scene, so Spanish naturally uses the definite articles:

• la regadera
• la maceta
• el cactus

Even when English might sometimes leave an article out in a simple label-like description, Spanish often keeps it. This is very normal and natural.

You mainly learn grammatical gender together with each noun.

Here:

• la regadera → feminine
• la maceta → feminine
• el cactus → masculine

Some general patterns help:

• Nouns ending in -a are often feminine, like maceta and regadera
• Nouns ending in -o are often masculine
• Words like cactus do not follow the basic -a / -o pattern, so you need to learn the article with the noun

A good habit is to memorize nouns as:

• la regadera
• la maceta
• el cactus

not just the noun alone.

The order is actually quite natural in Spanish:

• La regadera = subject
• está = verb
• detrás de la maceta, al lado del cactus = location phrases

Spanish often places location information after the verb, just as English does. What may feel different is that Spanish uses multi-word prepositional phrases like detrás de and al lado de, where English may use simpler single-word prepositions like behind or next to.

So the sentence structure is not strange; it is just using Spanish location expressions.

Because both phrases help locate the object more precisely.

• detrás de la maceta gives one reference point
• al lado del cactus gives another reference point

Spanish can stack this kind of location information naturally, just like English can:

• The watering can is behind the pot, next to the cactus.

The comma simply separates the two pieces of descriptive information.

Yes, often you could. Junto a and al lado de can both express the idea of being next to something.

Examples:

• La regadera está junto al cactus.
• La regadera está al lado del cactus.

There can be small differences in tone or style, but in many everyday contexts they are very similar. For a learner, al lado de is an excellent and very common phrase to know.

Here it is singular: el cactus.

Spanish cactus can be singular, and in many contexts the plural is also cactus. Sometimes you may also see cactos, but cactus is very common.

In this sentence, the article el clearly shows that it is singular:

• el cactus = singular
• los cactus = plural

Not here. Since the sentence refers to specific objects, the articles are needed:

• detrás de la maceta
• al lado del cactus

If you removed them, the sentence would sound incomplete or ungrammatical in normal usage:

• detrás de maceta ❌
• al lado de cactus ❌

So in this sentence, keep the articles.

The written accents show where the stress goes:

• detrás → stress on the last syllable: de-TRÁS
• está → stress on the last syllable: es-TÁ

That matters because Spanish stress is very regular, and accent marks often tell you exactly where to emphasize the word.

A rough pronunciation guide:

• detrás ≈ deh-TRAS
• está ≈ es-TA

In Spain, pronunciation may vary slightly by region, but the stressed syllable stays the same.