Compost. To date I can’t put my veges in but all the agrapanthus/leaves now noxious weed. I cut off the green leaves and add to my compost. We have tons of it here as well as Ginger which is excellent for the compost heap. Don’t forget to layer with brown vegetation. This will speed up the break down. On top of that seaweed, some soil, and also use as mulch around your trees/plants.