Puse el helecho, la orquídea, la suculenta y el geranio juntos.

Because puse is the yo form of the preterite of poner.

• Infinitive: poner = to put / to place
• Preterite: puse, pusiste, puso, pusimos, pusisteis, pusieron

This is an irregular verb in the preterite, so it does not keep the pon- stem.

In this sentence, puse means I put / I placed as a completed action in the past.

Spanish often leaves out subject pronouns when they are not needed.

So:

• Puse el helecho...
  means
• I put the fern...

The verb form puse already tells you the subject is I, so yo is usually unnecessary unless you want emphasis or contrast.

For example:

• Yo puse el helecho, no Marta. = I put the fern, not Marta.

In Spanish, it is very normal to repeat the article before each noun in a list, especially when talking about specific things.

So:

• el helecho, la orquídea, la suculenta y el geranio

sounds natural and clear.

In English, we often say:

• the fern, orchid, succulent, and geranium

or even just

• fern, orchid, succulent, and geranium

But Spanish usually prefers repeating the article here.

You could sometimes omit some articles in other contexts, but in a sentence like this, repeating them is very standard.

Because juntos agrees with the whole group, and the group includes at least one masculine noun.

Here the nouns are:

• el helecho — masculine
• la orquídea — feminine
• la suculenta — feminine
• el geranio — masculine

When a plural group includes any masculine noun, Spanish normally uses the masculine plural adjective:

• juntos

If all the nouns were feminine, you would use juntas.

Here, juntos means together.

It tells you that the speaker put all the plants in the same place or grouped them together.

So the sentence means something like:

• I put the fern, the orchid, the succulent, and the geranium together.

It is an adjective used in a way that feels a lot like an adverb in English.

Actually, that is exactly why it is la orquídea: nouns ending in -a are often feminine, and orquídea is feminine.

So:

• la orquídea

The accent mark in orquídea shows the correct stress.

Just remember that grammatical gender in Spanish belongs to the noun itself, not to the real-world object. A flower is not biologically feminine just because the noun is feminine.

Because geranio is a masculine noun, and nouns ending in -o are very often masculine.

So:

• el geranio

This is a good example of a very common pattern:

• -o ending → often masculine
• -a ending → often feminine

But remember these are patterns, not absolute rules.

Yes, and that is a very useful thing to notice.

In Spanish, suculenta can be used as a noun as a shortened form of:

• planta suculenta = succulent plant

Since planta is feminine, the shortened noun is also feminine:

• la suculenta

So in everyday speech, la suculenta simply means the succulent.

Not exactly.

In standard Spanish, you normally do not put a comma before y in a simple list.

So this is correct:

• el helecho, la orquídea, la suculenta y el geranio

In English, some people use the Oxford comma:

• the fern, the orchid, the succulent, and the geranium

But in Spanish, that final comma before y is usually left out unless there is a special reason, such as avoiding confusion.

Yes, if the context already makes clear which plants you mean.

• Puse el helecho, la orquídea, la suculenta y el geranio juntos.
• Los puse juntos.

In the second sentence, los means them and refers to the plants as a group.

Spanish often uses direct object pronouns like lo, la, los, las once the nouns have already been mentioned.

It can mean either, depending on how natural you want the English to sound.

• poner often means to put
• It can also be translated as to place

In this sentence, I put ... together is probably the most natural everyday translation, while I placed ... together sounds a bit more careful or formal.

It is pronounced with the stress on quí because of the accent mark:

• or-QUÍ-de-a

The written accent tells you where the stress goes.

That accent is important because without it, a learner might stress the word incorrectly.

Yes, sometimes Spanish word order is flexible.

The version in your sentence is very natural:

• Puse el helecho, la orquídea, la suculenta y el geranio juntos.

You may also hear:

• Puse juntos el helecho, la orquídea, la suculenta y el geranio.

Both are understandable, but the original sentence sounds especially natural because juntos comes after the list and clearly describes the whole group.