By Debbie Roland and
Emmy Ulmschneider
Master Gardeners
I love blue flowers in my yard and Cape Plumbago (Plumbago auriculata) is one of my favorites. It grows fast and can be grown as an annual in your yard or as a perennial in pots. It’s light blue phlox like flowers attract pollinators such as butterflies and bees. Deer will not usually eat it. Its Latin genus name plumbago means resembling lead and its species name auricualta refers to the earlike shape of the leaves. Do not confuse this plant with Hardy Blue Plumbago, Ceratostigma plumbaginoides, which is a low growing ground cover with vibrant, darker blue flowers. Both are often referred to as plumbago or Leadwort.
Cape Plumbago is native to South Africa which should give you some idea of the conditions it needs to perform at its best. In the tropics, it is an evergreen shrub that can reach 6’ tall although it is usually grown as a low hedge or shrub. In the West Texas area, Cape Plumbago thrives in part shade which means you will probably want to plant it in containers with good drainage. Situate the pot on your patio or deck and train it onto a trellis or prune into a more shrub-like bush.
Plant Cape Plumbago in good potting soil and water regularly during the time it is being established. Once established it is drought tolerant but regular irrigation produces the best and longest blooming flowers. Very high temperatures can cause the pale blue blooms to fade. Pruning is necessary to keep this plant in check. Be sure to prune any stems that cross or any that are damaged or look diseased. The pruning encourages new growth where the new flowers form. Deadhead the spent flowers throughout the growing season which will also encourage new growth. In early spring cut back one-third of your plant. Use a 10-10-10 slow-release fertilizer in the fall and spring of each year.
At Zones 8 to 11 Cape Plumbago must be moved inside before the first freeze in the fall and should be over-wintered in a room with a lot of light. Alternatively, you can cut back the stems and overwinter the potted plant in a cool basement or a frost-free area of your garage. If you want to branch out, you can try Cape Plumbago in your yard. In spring bury the potted plant, in the pot, up to the pot rim in your garden. Then, in fall when temperatures drop, you can easily dig up the entire pot and overwinter it in a frost-free area.
You can grow Cape Plumbago from seed, but it will not bloom until the second year. You can also take stem cuttings when the plant is at its best. Cape Plumbago can be an irritant to skin so wear gloves when you are working with it.
Blue is not an easy bloom color to find. So, for an attractive blue attention getter, try Cape Plumbago in your yard, your patio, or your deck.
If you have questions, call the AgriLife office in Odessa at 498-4071 or in Midland at 686-4700. Additional information, and our blog for access to past articles, is available at westtexasgardening.org. Click on “Resources.”
