Plumbagos

John writes~ I have planted some plumbagos in my yard. Recently, I noticed some of the leaves are turning yellow. Why would this be happening? I live in Texas.

A. I suspect lack of fertilizer and/or water. They need high light and heat, so your Texas location should be fine. But, when the humidity drops, the plumbagos many times produce yellow leaves and drop them. Check your watering and fertilizer techniques, as described in the culture recommendations below: Use a very well-drained organic medium with a pH of 5.5 to 6.0.

Maintain air temperature at 62 to 80 F (17 to 26 C). High light levels and warm temperatures promote the best branching.

When sown in January, plumbagos will flower in May under natural days. For Fall flowering, the plants may need long-day treatment after September.

Plumbagos are heavy feeders. Feed weekly with 200 to 300 ppm N in a complete fertilizer. Be sure to fertilize thoroughly.

Irrigation should run through the ground to avoid salt buildup. Grow on the drier side, but avoid wilting.

Pinching plumbagos produce bushier plants. Pinching may be done one or two times. Pinching will delay flowering about two weeks.

No major disease problems will arise if using good cultural practices. Thrips and aphids are the most common insect problems. Plumbagos do not show phytotoxicity symptoms to any pesticides if used at the proper rates as specified on the label. Home gardeners will see best results when they place plumbagos in full sun locations. These moderately drought-tolerant plants grow vigorously during hot weather. A perfect choice for the warm South, they can grow up to 6 ft. (1.8 m) tall to create a bushy, informal hedge, and also works well in mixed containers. In the North, plumbagos are best-suited to patio planters, growing to about 12 to 18 in. (30 to 45 cm) tall, with a slightly greater spread.