Assuming
House #3 is the Latin American (like how we are with House #1 being the Scarezone to House transplant [or I guess, the Scarezone to Tram to House transplant]) house; then looking at the significance to that of certain trees, two comes to mind; and that is the Palo Santo and the La Ceiba.
The Palo Santo, otherwise known as the Holy Wood tree; is known more properly as a tree that is meant for a tool in burning, for that of the Spiritual ceremony of Cleansing to negative energy. It is also used in some tribes as a means to connect the spirit of ourselves alongside that of our Creator.
The La Ceiba (or Kapok), is known however much more prominently; as the Sacred Tree of Life. The La Ceiba can be found in that of Mexico, but alongside that of Central America and the Caribbean's. The La Ceiba's significance is actively much more important to that of Latin American tradition; with Mayans, Amazonians, in other places such as Puerto Rico.
In the case of the La Ceiba, Mayans considered it as that of a link of sorts. To that of Heaven, Earth, and of what was below of Earth. In Puerto Rican customs, it is seen as a ladder for the deceased to travel to the Afterlife.
I think when looking to what Murdy spoke with House 3, the key lies to that of what exactly is being planted; in that of the trees and of the flowers that are connected to them.
EDIT:
Adding one more in--and I am going to give credit where it is due. From Twisted_Thrills on Theme Park Stop's Discord, they brought up another tree altogether; that being of the Protium Copal.
Protium Copal is more commonly used, via the resin within the trees for Offrendas; primarily around that of guiding the soul through that of the aroma. The Wheelbarrows could be then seen as flower planters; with Twisted bringing up that of Marigolds, and their importance to that of Dia De Los Muertos.
It is also good to note of La Catrina, in how she debuted for the 2023 HHN season in the Plaza.