Magistra dīcit hortum quasi novam fābulam flōrēre, cum rosae, lilia, et violae ūnā lūceant.

Because dīcit often introduces an indirect statement in Latin.

In English, we say:

• The teacher says that the garden is blooming.

In Latin, that usually becomes:

• Magistra dīcit hortum flōrēre.

In this construction:

• the subject of the reported statement goes into the accusative
• the verb of the reported statement goes into the infinitive

So hortus becomes hortum because it is the subject of flōrēre inside the indirect statement.

For the same reason: it is part of an indirect statement after dīcit.

Latin commonly uses:

• verb of saying/thinking/perceiving
  • accusative subject
    • infinitive verb

So:

• Magistra dīcit = The teacher says
• hortum flōrēre = that the garden is blooming

This is one of the most important Latin sentence patterns to learn.

Quasi means something like as if, as though, or like.

So hortum quasi novam fābulam flōrēre suggests:

• the garden is blooming like a new story
• or the garden is blooming as if it were a new story

It adds a poetic comparison rather than a plain factual description.

Because it is tied to hortum inside the same indirect-statement idea.

The garden is being compared to a new story, almost as if Latin is saying:

• the teacher says the garden is blooming as if it were a new story

Since hortum is accusative in the indirect statement, the phrase compared with it appears in the accusative as well: novam fābulam.

So this is not a direct object of flōrēre.
Instead, it is part of the comparison created by quasi.

It is a cum-clause with the subjunctive.

Here cum means something like:

• when
• since
• while

depending on how you understand the context.

The clause gives the circumstance or reason for the garden’s vivid beauty:

• when / since the roses, lilies, and violets shine together

So it is not just a simple add-on; it helps explain the scene.

Because cum very often takes the subjunctive when it introduces a circumstantial, causal, or more descriptive background clause.

So:

• cum ... lūceant = when/since ... shine

Lūceant is:

• present
• subjunctive
• active
• 3rd person plural

from lūceō, lūcēre = to shine, to glow

No. Here cum is a conjunction, not a preposition.

It means when, since, or while, not with.

So:

• cum rosae ... lūceant = when/since the roses ... shine

If cum meant with, it would be a preposition followed by an ablative noun, which is not what is happening here.

Because they belong to different noun types, but they are all still nominative plural, the subjects of lūceant.

• rosae = nominative plural of rosa
• lilia = nominative plural of lilium
• violae = nominative plural of viola

The important thing is not that they look the same, but that they are all plural subjects.

Also notice that lilia is neuter plural, so its plural ending is different from the feminine nouns.

Here ūnā means together or at the same time.

It is functioning adverbially, describing lūceant:

• rosae, lilia, et violae ūnā lūceant
• the roses, lilies, and violets shine together

So it is not the number one modifying a noun here. It is better understood as an adverb.

By English standards, yes; by Latin standards, not especially.

Latin word order is much freer than English word order because the endings show grammatical function. The sentence places words for emphasis and style.

For example:

• Magistra dīcit comes first to set up the main statement.
• hortum appears early to introduce the subject of the indirect statement.
• quasi novam fābulam is placed before flōrēre to highlight the poetic comparison.
• the cum clause comes afterward to paint the background scene.

An English translation would usually rearrange this more tightly, but the Latin order is natural and expressive.

Yes. Flōrēre can mean literally to bloom, but it can also suggest to flourish, to be radiant, or to be at its best.

In this sentence, because the subject is hortum, the literal sense of a garden blooming is obvious. But the comparison with novam fābulam makes the wording more imaginative, so the verb also carries a richer sense of beauty and vitality.