1st time-I found this N back yard & would really like 2 know what it is- I love trees
if your plant has milky sap when part of a leaf is torn it is one of our native milkweeds. It would be easier to identify it when it is in flower, it is in bud in your picture. My first impression is that it could be Asclepias viridiflora and my second guess would be Asclepias variegata. Flower color will distinguish those, variegata has white flowers and viridiflora has green flowers. Feel free to send more pictures with it in flower. It is a native perennial herb.
I apologize for the delay in my reply. I had software issues that only now have been fixed. Thank you for your patience.
Dr. Steven Hill, Botanist, SCNPS