Snape had been largely ignoring the people around him, his focus on the plants in the garden. When the young lady spoke directly to him, he pulled his attention away from the vine he'd been contemplating to look over at her.

"Yes."

Returning his attention toward the plants once more, he gestured with one hand toward those before them. "Do you happen to know if someone is allowed to remove a piece of the plants from this garden?" It would far easier for him to study the nature of the plants if he was capable of possessing a piece of them, than it would be to do guess work from notes on what he could observe of the plant.