Aligning (almost) perfectly a grass component to rectangular surface


I would be deeply thankful for any advice to achieve the following effect, please.
I would like to align grass components to a rectangular surface edges.
I have tried many option an I cannot achieve the effect. Either there is a some space between the edges and the grass or the component are placed partially outside the group border.

My goal is to fill the floral opening in a pavement with some vegetation so the bottom (ground) texture is completely covered.

Many thanks in advance.

What is an exact purpose of Jitter % and Rotation in Distribution setting?

Thank you in advance.

Hi George,

To achieve what you want, you need two setups. One using large patches of grass, the other much smaller patches that will be scattered only along the edges. Look at the Library, it has the two presets for each type of grass.

As for the jitter and rotation, take a look at this :

Thank you.