Truly blue flowering plants are somewhat rare. Blue is a “cool” color which tends to be related to calmness, relaxation, and serenity – always welcome in landscapes. The sky-blue flowering plumbago is one of those plants. While commonplace, this evergreen flowering shrub is great workhorse for foundation plantings, in planters, as a hedge or planted so that it cascades over a wall. The plumbago is an essential, easy-to-grow, and colorful subject worth some additional attention.
Native to South Africa, the plumbago is a fast-growing shrub that can grow over six feet tall and eight feet wide in time and without pruning. Best in full sun for superior flowering, this shrub will become fairly drought tolerant after establishment. Allow up to six feet between plants when planting in mass to promote the mounding, almost fountain-like growing habit that is natural for this woody plant. The yellow-green leaves frame the spectacular, one-inch-wide flowers that form clusters that may remind you of northern phlox. While most plumbago come in sky blue, there is a cultivar called ‘Royal Cape’ with cobalt blue flowers. For something different, there is also a white variety called ‘Alba’.
Plumbago can become very bushy, so, to promote new growth, prune this shrub relatively heavy in late winter. Although hardy in our area, frosts or freezes can nip plumbago back a bit as well. Even if it were frozen back to the ground, the plumbago will more often than not, grow back without a problem.
While plumbago have very few pests, an insect known as the chili thrips entered Florida in 2005 and had really taken a liking to many formerly low maintenance plants such as plumbago. The good news is that this insect problem seems to have leveled off in our area as natural predators have built up to suppress chili thrips to a point where damage is minimal to none. An additional item to note that may be mistaken for a pest is called a chalk gland. Chalk glands are found on the underside of plumbago leaves and are noted to excrete this natural white deposit – do not confuse this with a fungus or other pest.
One good insect to note is the Cassius blue butterfly (Leptotes cassius) which uses this plant is as a host for the larvae. This butterfly is equally fond of our Florida-native white plumbago.
Consider plumbago, a true Florida-Friendly Landscaping™ recommended plant, in your landscape for color and eye-appeal! For more information on a kaleidoscope of colorful plants to grow in our area, or to ask a question, you can also call the Master Gardener Volunteer Helpdesk on Mondays, Wednesdays, and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Ralph E. Mitchell is the Director/Horticulture Agent for UF/IFAS Extension – Charlotte County. He can be reached at 941-764-4344 or ralph.mitchell@charlottecountyfl.gov. Connect with us on social media. Like us on Facebook @CharlotteCountyExtension and follow us on Instagram @ifascharco.
Resources:
Gilman, E. F., Klein, R. W. & Hansen, G. (2024) Plumbago auriculata. Plumbago, Cape Plumbago, Sky Flower. The University of Florida Extension Service, IFAS.
UF/IFAS Gardening Solutions (2024) Plumbago. The University of Florida Extension Service, IFAS.
The Florida-Friendly Landscaping Guide to Plant Selection & Landscape Design (2022) The University of Florida Extension Services, IFAS.
Hansen, G. & Alvarez, E. (2019) COLOR IN THE LANDSCAPE: FINDING INSPIRATION FOR A COLOR THEME. The University of Florida Extension Services, IFAS.
Hall, D. W. & Butler, J. F. (2019) Cassius blue, tropical striped blue. Entomology and Nematology Department. The University of Florida Extension Services, IFAS.
Landre, C. (2024) Blue Plumbago. South-Florida-Plant-Guide.com.
FFL Gardens (2024) Plumbago. The University of Florida Extension Services, IFAS.
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