3/23 Vertical Mulch Update

VERTICAL MULCH UPDATE

USC South Watt Plot

By Nina Weithorn
Test Plot Intern

March 23 2023

This was a quick observation after the historic amounts of rain Los Angeles has received over the past two months. These observations were made around 12:30pm on a Thursday. A drone was used to take aerial shots of the plots and documentation of the flowering species was done.

vertical mulch test (L) control plot (R)

vertical mulch marked by stone piles, they are 36" deep x 12" wide

Weather

High of 54, low of 45 degrees Fahrenheight. Sunny for a change.

How are the plants doing?

The plants are all looking healthy and vibrant after the rain. The Diplacus aurantiacus, Heuchera rosada, and Lepechinia fragrans are all flowering.

What is Vertical Mulch?
Vertical mulching is a way to address soil compaction and allow for increased water infiltration into the root zones of plants. The process of vertical mulching involves digging a hole or trench at least 1 foot deep adjacent to plants and replacing the soil with wood chips. When water is poured into the vertically mulched area, it immediately reaches the deeper roots of established plants or encourages deep root growth of new plantings.

Field Notes

The growth around the vertical mulch holes does not appear to be significantly different from the adjacent plot with no vertical mulch. We have not been systematic about controlling water from the automatic sprinklers so this is probably due to thte fact that vertical mulch holes have not been watered separately from the irrigation system.

Maintenance
Plots could use weeding as non-native grasses reappear after th rain. Additional mulch could be applied, especially before the hotter upcoming months.

Action items
Ask campus irrigation to turn off sprinklers so we can control by hand watering.