אני שותלת פרחים ליד החלון, ואחותי שותלת צמח בגינה.

Because the subject is feminine singular.

In Hebrew present tense, the verb agrees with the subject in gender and number:

• שותל = masculine singular
• שותלת = feminine singular
• שותלים = masculine plural / mixed plural
• שותלות = feminine plural

So:

• אני שותלת = I am planting, said by a woman/girl
• אני שותל = I am planting, said by a man/boy

The same is true for אחותי שותלת because my sister is also feminine singular.

It is the present tense.

In Hebrew, the present tense often covers both ideas that English separates:

• I plant
• I am planting

So אני שותלת פרחים can mean either:

• I plant flowers
• I am planting flowers

The exact meaning depends on context. In a sentence like this, English often translates it as am planting, but Hebrew itself does not force that distinction.

The verb agrees with the subject, not the object.

Here the subjects are:

• אני
• אחותי

Both are feminine singular in this sentence, so the verb is שותלת both times.

The objects are:

• פרחים = flowers
• צמח = a plant

These do not control the form of the verb here.

A learner might wonder whether פרחים being plural should make the verb plural, but it does not, because flowers are what is being planted, not who is doing the planting.

Yes, Hebrew can sometimes omit a repeated verb if the meaning is clear, but repeating it is very natural and often clearer.

So this sentence:

• אני שותלת פרחים ליד החלון, ואחותי שותלת צמח בגינה

is completely normal.

A shorter version such as:

• אני שותלת פרחים ליד החלון, ואחותי צמח בגינה

would be incorrect, because the second part would be missing a verb.

A version like:

• אני שותלת פרחים ליד החלון, ואחותי צמח בגינה

does not work in Hebrew.

If you wanted to avoid repetition, you would usually need a different structure, but in simple coordinated sentences, repeating the verb is the standard and safest choice.

Because את is normally used only before a definite direct object.

Compare:

• אני שותלת פרחים = I am planting flowers
• אני שותלת את הפרחים = I am planting the flowers

And:

• אחותי שותלת צמח = My sister is planting a plant / plant
• אחותי שותלת את הצמח = My sister is planting the plant

In your sentence, פרחים and צמח are indefinite, so את is not used.

Because ה is the Hebrew definite article, equivalent to the.

• חלון = a window

• החלון = the window

• פרחים = flowers / some flowers

• הפרחים = the flowers

• צמח = a plant
• הצמח = the plant

So:

• ליד החלון = near the window
• צמח = a plant
• פרחים = flowers (not specifically the flowers)

Hebrew marks definiteness directly on the noun with ה־.

It is written as one word, but it contains two parts:

• ו־ = and
• אחותי = my sister

And אחותי itself also has two parts:

• אחות = sister
• ־י = my

So literally:

• ואחותי = and-my-sister
• natural English: and my sister

Hebrew often attaches small function words and possessive endings directly to nouns.

בגינה contains the preposition ב־ meaning in.

The base noun is:

• גינה = garden

So:

• בגינה can mean in a garden or in the garden, depending on context and vowel marking

In fully pointed Hebrew, there is a difference:

• בְּגִינָה = in a garden
• בַּגִּינָה = in the garden

But in normal everyday Hebrew writing, the vowels are usually not written, so both appear as בגינה. You understand which one is meant from context.

Since the meaning is already given to the learner, you would follow that meaning here.

ליד means next to, by, or near.

So:

• ליד החלון = near / by / next to the window

It is used before a noun to show location:

• ליד הבית = next to the house
• ליד הדלת = by the door

It can also take pronoun endings:

• לידי = next to me
• לידך = next to you
• לידה = next to her

In this sentence, ליד החלון tells you where the flowers are being planted.

Yes, the place phrase can move, but the given order is very natural.

A basic Hebrew sentence often follows:

• subject + verb + object + place

So here:

• אני = subject
• שותלת = verb
• פרחים = object
• ליד החלון = place

That is why the sentence feels straightforward and neutral.

Hebrew does allow other orders for emphasis, for example:

• ליד החלון אני שותלת פרחים

This is also possible, but it gives more focus to near the window.

צמח is singular and פרחים is plural.

• צמח = plant
• פרחים = flowers

The ending ־ים in פרחים is a very common masculine plural ending in Hebrew.

So:

• פרח = flower
• פרחים = flowers

This means the sentence contrasts:

• one person planting flowers
• another person planting a plant

A learner may notice that פרחים is plural but translated simply as flowers, with no article, which is perfectly normal in both Hebrew and English.

Only the part with אני would need to change, because I would now be masculine singular.

You would say:

• אני שותל פרחים ליד החלון, ואחותי שותלת צמח בגינה.

Notice:

• אני שותל = I am planting, said by a male
• אחותי שותלת stays the same, because my sister is still feminine

This is a very common feature of Hebrew: even with אני, the verb still shows the speaker’s gender in the present tense.