My Plumbago Hardly Blooms And The Leaves Are Yellowish. I Live In Zone 9 Northern CA.

Question

Plumbago is large and sprawling and 7 yrs. old and used to be dark green and flower.

Answer 1

Unfortunately, your photos did not go through, so I am unable to give a good diagnosis. They are relatively disease resistant, which leads me to believe that it may have something to do with nutrient levels or moisture levels. I would suggest testing your soil, and making sure to water after the soil dries several inches on the top.

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-moisture-in-plants.htm

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm

https://www.gardeningknowhow.com/ornamental/shrubs/plumbago/growing-plumbago-plants.htm