For:
By: Daniel E. Mullins
Extension Horticulture Agent
Getting the Blues is Beautiful With Plumbago
Blue provides a cool, relaxed feeling in the landscape, yet some say that there is no plant that produces truly blue flowers. Well, Plumbago produces abundant flowers that are close enough!
Plumbago auriculata goes by such
common names as plumbago, skyflower
and leadwort. It is a tender evergreen
shrub that reaches three to five feet in height and width in
Though the foliage is attractive, it’s the flowers that are outstanding. Borne in clusters that are six inches across, individual blossoms look somewhat like those of phlox. The color has been described by many writers as azure-blue, but I prefer to call it powder blue.
I have come to appreciate Plumbago more over the past few years. Though it provides a rare color in the landscape there are other advantages. First, it blooms almost constantly for seven to eight months or as long as temperatures are relatively high.
This is not a temperate zone plant and an extra cold winter will do it in. However, many Plumbagos make it through our typical winters, come back and begin flowering in early spring. Even if some are frozen each winter, a plant that flowers for two thirds of the year is a good investment.
Second, few pest problems are seen on locally grown Plumbagos and third, they are readily available. Many retail nurseries offer them as container grown plants, with one gallon containers being the most popular size.
Plumbago Growing at a Glance
● Select young, vigorous plants in a moderate size such as those grown in four inch, five inch or one gallon sized containers.
● Select a sunny spot and enrich the area by incorporating peat, manure or compost to a depth of six inches. Apply a light application of a balanced garden fertilizer and till again.
● For a mass effect, set plants approximately three feet apart. Plumbago can also be grown as a light vine if carefully trained. It is more of a scrambler than a twining vine, so it will need some help and will even require tying to the support.
● Once planting is completed, the soil surface in the bed should be mulched with a coarse material such as bark or pine needles.
● Water often until plants are well established and then taper off
on the frequency until they are irrigated only twice each week in the absence
of sufficient rainfall.
● Lightly fertilize during late spring
and again during the summer to keep plants vigorous.
● Clip or pinch away old flower clusters as soon as they
fade. This will help plants to repeat
the flowering cycle over and over.
Question of the Week: I have a large, old Southern Magnolia tree and some of the leaves do not
look well. There are brown and black
spots and some of the leaves are turning yellow. What is the problem?
Answer: You have described a normal spring condition for this species of evergreen
Magnolia. It is preparing to shed some leaves. Even though the Southern Magnolia is an
evergreen, it loses part of its foliage each spring and replaces it with new
leaves.
The term evergreen is
somewhat misleading in that it might lead someone to believe that the same
leaves remain on the tree indefinitely.
This is not the case – imagine what a fifty year old leaf still hanging
on a tree would look like! Instead, evergreens
“exchange” leaves but not all at one time like deciduous species do.
Evergreen Magnolias
generally shed their two year old leaves during the spring. Just before leaf drop, chlorophyll and other
substances are removed and retained.
This causes imperfections that were previously masked by leaf pigments
to become evident. Assuming that your
tree is otherwise healthy, don’t worry about these old yellow and spotted
leaves. They will soon be replaced.