Significantly the aloe is part of the garden with Kezia does not like, the garden that is actually "no garden at all" because of the way that it is such a contrast to the domesticated other section of the garden that Kezia and the other residents of the house much prefer. The aloe then becomes a very important symbol of nature and the sublime in its full description, and it is highly notable that it is associated with the sea
...the high grassy bank on which the aloe rested rose up like a wave, and the aloe seemed to ride upon it like a shop with the oars lifted. Bright moonlight hung upon the lifted oars like water, and on the green wave glittered the dew.
The sea imagery clearly conveys something of the entralling power that the mysterious aloe plant has on the Burnell family. The aloe seems to be a symbol of the way that nature cannot be fully tamed. By extension, given that the Burnell family have just moved to a new house in the countryside, it is a subtle yet important reminder that the Burnell family are living in a land that is not their own and which they can never fully belong to. It references a history of a people who have been exploited and mistreated, and the natural vegetation, such as the aloe, are powerful, tangible and profoundly unsettling reminders of such realities.