1225 plants are to be arranged in a garden. The number of rows is equal to the number of plants in each row. How many plants are in each row?

The problem states that 1225 plants are to be arranged in a garden such that the number of rows is equal to the number of plants in each row. This means if there are $x$ rows, there are also $x$ plants in each row.

The total number of plants is the product of the number of rows and the number of plants in each row.
Total plants = (Number of rows) $\times$ (Number of plants in each row)
Since the number of rows and plants per row are the same, let this number be $x$.

To find $x$, we need to calculate the square root of 1225.

We can find the square root by prime factorization or by estimation.
Let's use prime factorization:
1225 ends in 5, so it's divisible by 5:
$1225 = 5 \times 245$
245 also ends in 5:
$245 = 5 \times 49$
49 is $7 \times 7$:
$49 = 7^2$
So, $1225 = 5 \times 5 \times 7 \times 7 = 5^2 \times 7^2 = (5 \times 7)^2 = 35^2$.

The number of plants in each row is 35.