Express-News Weekly Article
Saturday, May 20, 2006
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist 
“Summer Color - Caladium, Coleus, Lantana, and Vincas”  

            Have you ever considered a foliage plant for summer color in the shade?  In the north, the favorite foliage plant seems to be hostas.  Unfortunately, here in our area hosta last about two days before the slugs and snails devour them.  Caladiums and coleus have a better record.  Slugs, snails, and pill bugs will eat some of the foliage (especially caladiums), but they can be easily controlled with a bait or even beer traps.

 

            Beer traps involve sinking a plastic cup to be level with the soil surface every six feet in the planting area.  Half fill the trap (cup) with beer and the pests will fill it up in a suicidal dive.  Beer trap experts report that cheap or stale beer is just as good as premium beer, but they would prefer that fact not become common knowledge.  They apparently justify the purchase of their favorite beer as the one being best for control of pests as well! 

 

Caladiums are available in two basic colors, pink and white, and two basic types.  The “fancy leaf” are generally heart-shaped and only prosper in shade.  The “strap leaf” are less rounded and have more length than width.  They actually have relatively good sun tolerance in addition to being shade-tolerant.  Some of the many “strap leaf” selections are “Red Ruffle,” “Miss Muffet,” and “White Knight.” 

 

            You will probably be amazed by the colors that are available in coleus.  I think the most spectacular are the deep burgundy (Burgundy Sun), and yellow-green (Solar Flare).  Many selections have combinations of red, white, and green on the same plant.

 

     Lantana is another blooming plant to consider for hot weather.  All lantanas are perennials that usually die back to the ground in the winter.  Lantanas are desirable because they are good xeriscape plants, are not usually eaten by deer, and have good resistance to disease and insects.  The blooms are usually cyclical, in that they bloom for six weeks, rest for six weeks, and then bloom again.  Area landscapers have speeded up re-blooming by deadheading the planting every three or four weeks.  A light (.5 inches deep) pruning with the string mower stimulates the new flush of flowers.

 

There is one insect that reduces lantana blooms some years, the lace bug.  The little beetles suck the juices from the plants just like spider mites, scale or aphids.  The symptom is the same as well; the foliage becomes dusty or milky looking.  The plants recover, but a spray of acephate at first sign of a symptom will eliminate the problem.  Organic gardeners can try neem oil to control lace bugs. 

 

There are many choices of size and growth habit among lantanas.  The most popular are the spreading lantanas such as “New Gold.”  One “New Gold” plant in good soil will cover four feet in every direction.  It dies back to the roots every winter.

 

There are a number of small mound and larger shrub lantanas.  Check and see what your nurseryman has to offer, every year there are new offerings. 

 

Vincas (also called periwinkle) used to be the favorite annual flower in the United States.  It blooms constantly until cold weather arrives, is generally deer-proof, qualifies as a xeriscape plant, and was not bothered by insects.  Its popularity has been reduced, however, because it is very susceptible to a fungus disease – aerial phytophera.  The disease attacks the foliage and stems with the result that they melt down unpleasantly. 

 

Vincas are still a good choice for summer color if you take some precautions to prevent aerial phytophera.

 

·      Aerial phytophera is a fungus that requires moisture on the foliage to infect the plants, so wait until the humidity is relatively low to plant them.  Mid-May is usually a good time.

 

·      Vincas do best when they are watered infrequently.  Once every two weeks after they are established is usually plenty.

 

·      Water with drip irrigation or flooding the soil.  Sprinkling overhead results in infected plants. 

 

·      Mulch the vinca bed to reduce the need for watering.  The mulch also reduces splash from the soil.  The disease organisms are in the soil.

 

Vincas are available in several sizes and color variations.  Lavender, white, and near reds are available.  There are many bicolors in the three colors.  Plant vinca in full sun.