True Blue

Blue flowering plants really catch my attention.  One of the plants that is catching my eye these days is the sky-blue flowering plumbago.  This evergreen flowering shrub is great for foundation plantings, in planters, as a hedge or planted so that it cascades over a wall. While seen in almost every home landscape, the plumbago is an essential 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 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. Chili thrip-infested plumbago almost looked like they have a fungal disease due to the numerous blackened leaves.  The good news is that this insect problem seems to have abated and has leveled off in our area as natural predators have built up to suppress chili thrips to a point where damage is minimal to none. 

One additional item to note is that plumbago have what are called chalk glands on the underside of their leaves.  This white deposit is natural and should not be confused with a fungus or other pest. 

Consider plumbago, a true Florida-Friendly Landscaping™ recommended plant, in your landscape for color and eye-appeal.  For more information on a “rainbow” of colorful plants to grow in our area, please call our Master Gardener volunteers on the Plant Lifeline 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.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.

Resources:

Gilman, E. F. (2011) Plumbago auriculata. Plumbago, Cape Plumbago, Sky Flower.  The University of Florida Extension Service, IFAS.

Scheper, J. (2011) Plumbago auriculata.  Floridata.com.  Tallahassee, FL.

Ferrer, A. (2014) Plumbago. The University of Florida Extension Service, IFAS – Seminole County.

Caldwell, D. (2006) Chili Thrips: New Thrips Found on Plumbago: Could Mean Serious Losses for Ornamentals and Veggie-Fruit Industries. The University of Florida Extension Service, IFAS – Collier County.