Beautiful Moth & Savannah Grass

University of Florida/IFAS Extension Director for Nassau County, Rebecca Jordi, provides expertise and tips about landscaping and gardening in northeast Florida.

QUESTION: I would like to plant a different kind of ornamental grass in an area of my yard. Any ideas? KM

Savannah Ruby Grass Image, Nassau County, Florida Extension, Melinis nerviglumis
Savannah Ruby Grass, Melinis nerviglumis

JORDI: We are trying out a new ornamental grass called Savannah ruby grass, Melinis nerviglumis ‘Savannah’.

We are getting different pieces of information about it, but we are going to try it in our demo garden anyway. Some say to treat it as an annual, others say a tender perennial. Both of those mean it might not last too long. So, be prepared.

First thing to know about the demo garden, we have no irrigation and it will be placed in a very tough area – the parking lot median. The soil is terrible, and the area is hot and miserable. Plus, people back their trucks on top of the plants and walk all over the plant material. This means, if it lasts more than one year, it should do fine in your landscape.

Most plant nurseries say it is fine for USDA cold-hardiness zones 7-11. Supposedly, it is great for full sun to part shade, grows well near walkways, is drought and high heat tolerant.

The leaves have a blue-green color and the seed head starts out dark pink, fades to a pale pink then finally turns white. Such a pretty combination. It has the potential for growing up to 3 feet tall. We shall see.

Be sure to visit the demo garden located at 96135 Nassau Place, in Yulee, and check out the variety of grasses in the median. Feel free to pull weeds while you are there – we appreciate any help we can get! Oh, and please don’t back your truck over our plants – the exhaust burns the plants. Thanks.

QUESTION: I saw this unusual insect and wanted to know what it was. I have attached a photo. ER

Scarlet-Bodied Wasp Moth, Cosmosoma myrodora (Photo UFIFAS)
Scarlet-Bodied Wasp Moth (Photo UFIFAS)

JORDI: Wow, this is beautiful! I am so jealous you had a chance to spot this pretty moth. It is a native scarlet-bodied wasp moth, Cosmosoma myrodora. It is generally found only along the coastline of Georgia, throughout Florida and over to the coastline of Texas.

Because of its striking adult coloration, including a bright red thorax and abdomen, and transparent wings patterned with black, this moth immediately stands out in Florida landscapes. Larval feeding is restricted to two native plants in the genus Mikania, family Asteraceae.

The scarlet-bodied wasp moth completes its life cycle in 50 to 60 days. Development times for larva and pupa are 7 days and 11 days, respectively (Castillo 2012). Locally, the larvae feed on the native climbing hemp vine (Mikania scandens). Adult males of the scarlet-bodied wasp moth feed on dog fennel (Eupatorium capillifolium). The male eats the dog fennel to obtain an important alkaloid. The alkaloid from the dog fennel is passed on to the female during mating. The female will then pass this same alkaloid to the eggs. The alkaloid helps prevent the eggs from being parasitized by predators.

Nature never ceases to amaze me. Be sure to read the publication from the University of Florida’s Entomology Department (Featured Creatures – the mating process is interesting.)

Rebecca L. Jordi
Nassau County Extension Director
UF/IFAS Environmental Horticulture
543350 U.S. Highway #1
Callahan, FL 32011