Let's take the length of the side of rectangles to be a and b, respectively, such that a>b

Once we find a, we can also find the perimeter of the semi-perimeter since the radius of the semi-circle would be (a/2)

Using statement 1 alone:
This statement gives us that 2(a+b)=28; since we can not find the value of a or b alone, we can not determine the perimeters of the flower bed

Using statement 2 alone:

We get that $$a^2+b^2=100$$, which alone is insufficient in finding the values of $$a$$ and $$b$$. 

Using both statements together, we get the following:

$$a+b=14$$ and $$a^2+b^2=100$$
Using the formula, $$\left(a+b\right)^2=a^2+b^2+2ab$$, we can get the value of $$ab$$.
And using these, we can get the value of a-b through
$$\left(a-b\right)^2=\left(a+b\right)^2-4ab$$

Once we have a+b and a-b, we can find the values of a and b individually. 

Thus, with both statements taken together, the perimeter can be determined. 

Therefore, Option C is the correct answer.