Q & A: North Florida Gardening Tips

EDITOR'S NOTE: A University of Florida/Nassau County Cooperative Extension Service Horticulture Agent, Ms. Jordi addresses some of the questions she receives about landscaping and gardening in North Florida, in the GARDENING ZONE.
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Bird's Nest Fungi

QUESTION: I have this round mushroom like structures growing on my mulch. What are these growths? MF

MS. JORDI: These fungi look like birds nests, with eggs inside hence it’s name – Bird’s Nest Fungi. Like a lot of the fungi, they have an amazing and unique way of reproducing. The little nests pop open, to reveal flattened spores. When raindrops fall into the nest the little spores are splashed out. What is even more fascinating is that each spore is attached to the inside of the nest by a long thread, with a sticky end. As the spore flies out of the nest, the thread uncurls, and is stretched. Eventually, the thread breaks away from the nest completely. Then it swings around whatever leaf, twig or grass happens to get in its way, and sticks to it. In this way, the spore is firmly attached, and can safely start to grow into a new Birds Nest Fungus. They are often found in well-rotted wood debris and are not considered pathogenic or disease causing. Be watchful of your watering practices and remove the fungi as soon as they are located.

QUESTION: I love the beautiful shrubs I see in the ditch everywhere in our area. They are blooming beautiful orange flowers. One of the new local stores is carrying them, but I would like to propagate them. What are they called? JD

Sesban

MS. JORDI: The shrub you see is quite stunning. It is sometimes called Spanish Gold, Rattlebox, Rattle-bush or Sesbans. I believe the one you are referring to is classified as “invasive exotic.” An invasive exotic plant is a plant that can sustain itself outside of cultivation, outside its native range and disrupts naturally occurring native plant communities. That means it is taking over many of our natural shrubs in our managed and disturbed areas. If it is the invasive species, it is called Sesbania punicea (CAV.) Benth (Purple Sesban). I am not sure why it is called Purple Sesban, because it is definitely not purple!

The Sesban group of shrubs was introduced from tropical areas but the invasive Purple Sesban is a native of South Africa. The Purple Sesban is frequently found in central and northern Florida in tidal marshes and disturbed sites. It flowers from spring to fall, which is why you are seeing it now. It generally dies back during the winter, but comes back once temperatures increase. Although it is beautiful, it is best not to propagate a plant classified as invasive. One other side note – according to Cornell University the Purple Sesban is toxic to goats. Does that mean it can be toxic to other mammals? I don’t know, but I would not be willing to risk my dog on such a gamble.

QUESTION: I have a small pear orchard and I noticed last year some of the fruit had light, hairy fuzz on the fruit. This year the fuzz is on all the fruit and it has developed into pale orange spikes. Nearby cedars are turning brown. What is going on in my orchard? LW

Cedar Apple Rust

MS. JORDI: What you have on the pears is called Cedar Apple Rust. The causal agent of Cedar Apple Rust is the heteroecious basidiomycete Gymnosporangium juniperi-virginianae. No, you do not need to memorize that or even know how to pronounce it – thank goodness! By definition this rust fungus requires two hosts to complete its life cycle. Cedars (members of the genus Juniperus) usually have the most visible symptom of the disease in the early spring as the orange gelatinous finger-like structures called teliohorns are produced. Spores produced in these teliohorns are blown to susceptible apple or pear trees where they germinate and infect. In late summer the spores are blown back to the cedar where galls are initiated, grow, and mature the next year. In the spring following a year’s growth on the cedar, the galls give rise to teliohorns and the cycle is complete. It takes two years to complete the disease cycle. Cedar apple rust is not uncommon in Florida but is not considered much of a threat. The disease causes great concern in states where apple orchards are big cash crops. One method of control is to get rid of one of the host trees, which is often impractical. Pruning and removal of infected branches is helpful and fungicides are available. Be sure to follow the directions on the fungicide label for best results. For more information on growing pears check out the University of Florida’s website publication at http://edis.ifas.ufl.edu/MG072.

Sweet Woodruff

QUESTION: I am interested in using an herb called Sweet Woodruff as a ground cover in a shady location. What can you tell me about it? LG

MS. JORDI: Sweet Woodruff, Galium odoratum, is a short perennial ground cover or spreading herb, which can be used for tea or sachets. Bright green foliage is in a whorled pattern around the stem. When the leaves are crushed it produces an odor similar to freshly mowed hay, hence its species name “odoratum”. Small white flowers appear in late May or early June. It is a native to Europe and the Mediterranean areas and can be grown in zones 4-8. It prefers shady, moist rich soils with cool summers. As you may have already guessed, it would not be the best choice for North Florida’s hot, humid summers, which sometimes last more than 3 months. Even in cooler climates, Sweet Woodruff exhibits dieback due to hot conditions, but it will revive once cooler autumn conditions return. All the information I could locate regarding this herb came from cooler more northern states. In addition, it apparently can become invasive under optimum conditions. In North Florida we have other choices of ground cover for partial shade areas such as Japanese jasmine, Mondo grass, or ivy just to name a few.

Black-and-Yellow Mud Dauber

QUESTION: I have found a black wasp with yellow legs and yellow markings. It appears to be making mud structures on the top level of my house. What is this insect? GN

MS. JORDI: This beautiful insect is called a Black-and-yellow mud dauber, Sceliphron caementarium. It is mostly black with a large yellow spot on the prothorax, thorax, pedicel (waist), and 1st abdomen segment. Legs are mostly yellow and the wings are brown to black. The adults drink nectar and the larvae feed on spiders. The Black-and-yellow mud dauber is found throughout North America in meadows, settled areas, as well as overhanging roofs of buildings. The females build the mud, tubular cells. Each cell is stuffed with a paralyzed spider and a single wasp egg. The egg develops into larvae, which will feed on the spider. (I hope you are not reading this during breakfast.) Males are rarely seen before mid-summer but have been sighted visiting flowers for nectar in late summer and fall. Neither the male nor the female mud dauber are prone to stinging unless provoked and generally pose no threat to man except for the unsightly mud homes.

QUESTION: My builder put in “Mercedes” St. Augustine grass and I am now having trouble maintaining it. I just hired a lawn service to take care of it but I wanted more information about this particular variety. LM

MS. JORDI: Stenotaphrum secundatum “Mercedes” is a specific cultivar of St. Augustine grass. It is most often grown in more climates further north (northern Mississippi) and, therefore, it appears to be more cold tolerant. The University of Florida has done no extensive research on this particular cultivar but it appears to be susceptible to insect and disease like any other St. Augustine grass. It is important to remember that even the best grass will perform poorly if our cultural practices are improper. The best cultural practices: water only as needed (when grass blades begin to fold or turn a dull blue-green) usually once a week; water in the morning hours only; water Ѕ deeply but less often; use 15-0-15 or 16-4-8 as fertilizer; apply fertilizer according to directions during March, April, May and September; mow at highest height; and keep mower blades sharp. Let your lawn company do the job for which you are paying them. Refrain from going behind them and adding additional pesticides, lime, or fertilizers to the lawn - this can complicate the problem.

QUESTION: My pittosporum has scale on the stems, along with dark moldy stuff. I have been spraying insecticidal soap and horticulture oil but the shrub doesn’t look any better. I water them every 3 days and have been using a liquid fertilizing too. What is wrong with this shrub? MF

Florida Wax Scale

MS. JORDI: Pittosporum, pittosporum tobira, is an evergreen tree or shrub that matures to a height of 6 to eight feet, although it has a potential of reaching 20 feet heights. It is grown throughout Florida as a barrier, hedge, or screen producing a fragrant white flower in the winter. Pittosporum can be grown in full sun or partial shade in a variety of soils; it is salt, heat, and drought tolerant. The problem you are having may be the result of over-watering and over-fertilizing, which is not an uncommon error. Most adult shrubs and trees do not require fertilizing (exceptions are plants such as azaleas and gardenias). The scale on the pittosporum stems is probably Florida Wax Scale, a soft-bodied scale, which is notorious for secreting large amounts of honeydew on which the mold forms. The scale can be hand removed, but the soap and oil will work better once irrigation has ceased. Good luck.
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Rebecca Jordi
Extension Horticulture Agent
University of Florida/Nassau County Cooperative Extension Service
eMail: rljordi@mail.ifas.ufl.edu

(904) 879-1019
Fax: (904) 879-2097
972 S. Kings Road
Callahan, FL 32011

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