Q.Blue Plumbago
We planted Blue Plumbago in flower beds the end of February this year. At first they bloomed and grew; however, the past month the leaves are yellow and plants look spindly instead of vibrant/healthy green. Our sprinklers water 3X per week for about 30 minutes; we live in zone 8b (Texas). Are they getting too much water? Not enough water? Need fertilizing? Our landscaper planted them. Thank you!
You will need to check the soil moisture level to determine if watering schedule is appropriate.
One of the good things about blue plumbago is that it's moderately tolerant to drought conditions, especially once it’s established in the landscape. Depending on the weather, a newly planted plumbago should be watered once or twice weekly while the roots are becoming established in the landscape. Thereafter, watering once every week or two is sufficient. Root systems should be fully established approximately six weeks after planting.
Blue plumbago isn’t a heavy feeder and only requires an application of an all-purpose fertilizer blend twice yearly. Apply once in springtime and again in summer while it's actively growing. Follow package directions for the proper amounts and spread the fertilizer under and around the shrub. After application, water the product into the soil and rinse off any that may have landed on the foliage to prevent burning. Feed plants grown in containers a general-purpose, water-soluble blend, following package directions and fertilizing during the same time frame as plants grown in the garden.
https://www.gardeningknowhow.com/ornamental/shrubs/plumbago/growing-plumbago-plants.htm
