Black olives browning

With the increase planting of black olives (Bucida buceras) in our area, a nuisance pest has come along with it – the bucida caterpillar.  Normally more abundant south of us, this moth has worked its way up to Charlotte County.  While black olives are not fully hardy in all parts of Charlotte County, they are a beautiful tree.   When a problem pops up on them, people start to take notice.

Normally black olives, especially the very popular cultivar, ‘Shady Lady’ are nice and green.  But in recent years, during April and May, the tiny caterpillars of the nondescript gray moth called Characoma nilotica,  begin to feed and cause some defoliation on black olives.  The caterpillars are so inconspicuous that they are often not even noticed until the damage is well underway.  The only time these caterpillars may actually “fly in your face” is when they are hanging by silken threads from the tree earning them the name “bungee caterpillars”.   They eat the flowers first and then progress to the leaves which gives the black olive a brown, haggard look.  As they complete their life cycle, they used clipped leaves to make hiding places to produce white cocoons and pupate.  These little white cocoons are fairly easy to see and are particularly distinctive. 

Now for the good news – the infested black olive will re-foliate and be back to new in four to six weeks!  The nuisance of these caterpillars is short-term and there is generally no lasting damage or stress.  As such, the need to manage or control these insects is often not necessary.  If you wanted to attempt a control effort, you would have to start monitoring earlier to detect the minute young caterpillars.  The use of the caterpillar insecticide  Bt or Bacillus thuringiensis could help reduce the  damage, but there would only be a small window of opportunity to make the application(s) as per label instructions. 

Regardless, the black olive tree is a nice addition to our landscapes – especially in coastal Punta Gorda and in protected microclimates in Port Charlotte.  A tiny problem like the bungee caterpillar should not discourage you as its damage is minor and the blemishes caused are not long-lived.  For more information on all types of insect pests, 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 .

Resource:

Caldwell, D. (2008) “Black Olive” or Bucida Caterpillar (Characoma nilotica) a Nuisance Pest.  The University of Florida Extension Service, IFAS. 

Ornamental asparagus – not a fern

While you can’t successfully grow edible asparagus in Southwest Florida due to our overly warm and wet climate, you can grow a number of ornamental types that make great container plants for patios, indoors as houseplants, or in some cases, as a groundcover. 

Ornamental asparagus are often labeled as ”ferns” due to their sprays of fern-like foliage.  These plants are not true ferns, but do have fine, leaf-like branchlets called cladophylls which give them their unique ornamental fern-like quality.   Located on their woody, wiry stems, the hardly noticeable true leaves are scale-like in appearance.  Ornamental asparagus also have small spines on their stems so watch how you handle them.  Small white or pink flowers are followed by red or orange inedible fruit.  Birds enjoy the fruit and tend to spread the seeds around. 

Probably the most common ornamental asparagus available is Asparagus aethiopicus, also known as  Sprenger's Asparagus Fern – you can find it in nearly every garden center.   A friendly warning - Sprenger's Asparagus Fern is considered a Category I invasive plant by Florida Exotic Pest Plant Council.  This ornamental asparagus plant has escaped cultivation and is in natural areas in Florida where it is displacing native species.  Both seeds and tubers help propagate this plant in places it should not be found.  I have seen it naturalized in multiple places in Charlotte County.  While not recommended, if you keep this asparagus plant, maintain it in containers only (not in the ground) and under your watchful eye. 

Myers Asparagus Fern, commonly called the foxtail fern, is a cultivar of A. densiflorus named after its similarity to a fluffy, plume-like tail.  This asparagus is a beautiful perennial plant suitable for containers, as a houseplant, or as a groundcover.  The foxtail asparagus can be easily divided and propagated from time to time if it outgrows its space. 

Perhaps my favorite ornamental asparagus is the one called Ming or Asparagus retrofractus.  The full, deep-green cladophylls remind you of miniature pine trees.  The leaf-like cladophylls almost appear as mini pompoms which bring a special attractiveness to this less common plant.

A final type of ornamental asparagus that you may find in garden centers as a houseplant is the Asparagus setaceus, commonly known as Lace Fern or Climbing Asparagus. The asparagus has very fine and lacey cladophylls on vine-like stems.  I would keep this one in a container as it is likely to get out of control when planted in the landscape.  There are a few cultivars available which have dwarf forms or more upright growth habits. 

Grow your ornamental asparagus in full sun to part shade in a well-drained soil for best results.  They are fairly drought tolerant so do not overwater.  Besides being featured as an attractive foliage plant, many ornamental asparagus are also used as cut foliage in floral arrangements, boutonnieres and corsages.    

Ornamental asparagus are elegant, easy-to-grow plants.  Just keep them under your control and don’t let them accidentally escape!  For more information on all types of plants suitable for 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:

Rogers, G. K. (2013) Landscape Plants for South Florida – A Manual for Gardeners, Landscapers and Homeowners Sprenger’s Asparagus “Fern,” Foxtail “Fern” – Palm Beach State College.

Florida Exotic Pest Plant Council ’s 2015 List of Invasive Plant Species - http://www.fleppc.org/list/2015FLEPPCLIST-LARGEFORMAT-FINAL.pdf

Mueller, C. W. (2008) Asparagus Ferns (Asparagus species). Texas AgriLife Extension Service Texas A&M University, College Station, Texas.

Asparagus setaceus - http://en.wikipedia.org/wiki/Asparagus_setaceus.

Christman, S. (2000) Protasparagus setaceus . Floridata.com, Tallahassee, Florida.

Scheper,  J. (2007) Protasparagus densiflorus.  Floridata.com, Tallahassee, Florida.

Gilman, E. F. (2011) Asparagus densiflorus 'Sprengeri' Sprengeri Asparagus Fern.  The University of Florida Extension Service, IFAS.

Gil, D. (2009) Consider growing asparagus ferns.  LSUAgCenter.com  

The garden of cast iron

Some plants receive common names concerning how well they succeed in the garden.  One plant that deserves its name is the Aspidistra or “Cast-Iron Plant”.  Hardy and shade-loving, the cast-iron plant makes a great groundcover that slowly fills in an area without being invasive.  Originally from China, this Victorian favorite comes in a number of varieties from dark green to variegated patterns. 

Basically, the cast-iron plant, a member of the lily family, has simple, twelve to twenty-inch leaves, with smooth margins and parallel veins.  The leaves emerge from a rhizome as the plant develops into a clump.  Cast-iron plants are famous for their ability to grow in low light (even heavy shade), high heat, poor soil and even some drought.  This plant really cannot tolerate sunny areas, but does compete well with tree roots.  Good drainage is essential, but having the very best soil is not.  While you can fertilize sparingly during the growing season, you can also neglect this chore and still have good looking plants.  Start with potted transplants set in the landscape at twelve to eighteen inch intervals.  You can also take established plants and divide the rhizomes.  Water until established, but keep in mind that cast-iron plants are very drought tolerant. 

During the Victorian era, cast-iron were grown as an indoor container plant.  The cast-iron plant will make a good container plant inside or outdoors on a shady porch or patio.  Also consider that the leaves of the cast-iron plant make great additions to a flower arrangement.  As a matter of fact they will last in a vase as filler for at least a month. 

There are a number of cultivars to choose from and you will be surprised by the selection.  The cast-iron plant is occasionally available locally, but an Internet search will help you locate some of the rarer types.  One that I have seen available locally is called ‘Starry Night’ also known as ‘Ginga’.  This cultivar has shiny green leaves with creamy-white spots and streaks.  ‘Milky Way’ is another speckled type similar to ‘Ginga’, but has shorter and narrower leaf blades.  ‘Milky Way’ was even recognized as a Florida Nursery, Growers and Landscape Association (FNGLA) 2006 Florida Plant of the Year.   ‘Okame’ or ‘Variegata’ is another cultivar that has light green and white streaked markings.  This cultivar tends to grow slow and the color is variable and can even revert back to pure green.   There are many other varieties which range in color and leaf blade length and width.    Grown mainly for their foliage, the cast-iron plant does produce unique maroon-colored flowers near the base of the plant.

So, if you have a shady area where nothing else seems to grow, you might check out the cast-iron plant.   Not only does it take the shade, it loves the shade and prefers it!  For more information on all types of plants known to be shade-tolerant, 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:

Stamps, R. H. (2012) Aspidistra Production and Use.  The University of Florida Extension Service, IFAS.

Gilman, E. F.  (2011) Aspidistra elatior Cast Iron Plant.  The University of Florida Extension Service, IFAS.

Christman, S. (2006) Aspidistra elatior. Floridata – Tallahassee, Florida.

Florida Nursery, Growers & Landscape Association (FNGLA) (2006)  Florida Plants of the Year.

Harrison, M. (2015) Cast Iron Plant Excels in Shady Gardens.  The University of Florida Extension Service, IFAS – Okaloosa County.

Rain Barrel & Rain Garden Workshop

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