I have just received a fair amount of aged horse manure and am wondering if there are plants I should not use it on. I have a veggie garden, many different flowers, some California natives, and many Salvias. Thank you.
Certified GKH Gardening Expert
Horse manure can be used to fertilize nearly any plant imaginable. You can apply it as is (aged like yours) or add it to your compost. Here is additional information: https://www.gardeningknowhow.com/composting/manures/horse-manure-compost.htm