EDITOR’S NOTE: A University of Florida faculty member and Nassau County Extension Horticultural Agent, Rebecca Jordi addresses some of the questions she receives about landscaping and gardening in northeast Florida, in GARDEN TALK. The Extension also offers helpful clinics throughout the year, providing assistance to local gardeners on Amelia Island and in the surrounding areas of Nassau County, Florida. __________
QUESTION: When do I prune my muscadine grapes? CD
JORDI: Muscadine grapes should be pruned between January and March in the Northeast Florida area.
According to a publication by the University of Florida you should prune any branches that are less than 3/16 inch in diameter, leaving 2 to 3 buds per spur. Remove most of the spurs located at the top of the trunk to prevent crowding and bushiness, which will interfere with harvest. Prune any arms that are not vigorous. Apply no more than 4 to 6 pounds of 6-6-6 or 8-8-8 per vine per year. Application of fertilizer should occur in late March, May and just after harvest. Split applications are more efficient than a single application.
Muscadines mature in August and early September and should be stored at cool temperatures until eaten or used for jellies or wine.
QUESTION: I have an orange tree I want to protect from the freeze. I am told I can run water over it and it will protect it from freezing but it seems like a waste of water. What should I do? RC
JORDI: In order to totally protect the tree by water, you would need to start the water before the freeze and continue to water it after the freeze has passed. Although this procedure is used in citrus groves, is it not recommended for the homeowner. As you indicated, it is a terrible waste of water and not totally fool proof. In addition, citrus is especially sensitive to root rots which can be caused by excessive water – not a condition you want to encourage by adding too much water.
Most of the oranges we grow in this area are grafted onto cold hardy root stock, so there is less chance of losing the tree from freeze damage. The portion of the tree you truly need to protect is the grafting part (where the root stock meets the scion). The scion is the upper portion of the tree which produces the desired fruit. You can place an insulating type fabric over this area during cold, freezing temperatures to protect the tender upper part of the tree. Plus, you can place a fabric bed sheet or plastic over the top portion. Be sure it reaches the ground so you can trap the warm air coming off the ground to help keep the tree warm. Remove the sheet or plastic once temperatures increase above 30 degrees, or once the sun comes out. Watering your tree properly prior to the freeze is also helpful. Cold frames can be built to cover the whole tree, but that should not be necessary for citrus trees grown here.
QUESTION: Is it possible to grow red raspberries in North Florida? If so, what varieties? RW
JORDI: According to the University of Florida, raspberries are difficult to grow here as perennials and the flavor of the berries is fair to poor. Raspberries are typically grown in the north so I do not want you to be discouraged if yours do not do well. It is not you, it is the plant. Here is an section from one of our publications: “Dorman Red” is the only raspberry cultivar recommended for trial in Florida when grown as a perennial crop; however, berry flavor is poor to fair. “Heritage” raspberry has been grown as an annual crop during the winter in the southern parts of the state after it receives its chilling requirement. Here’s a link to the complete publication for your perusal. http://edis.ifas.ufl.edu/hs104 .
I have also included a link to a publication from North Carolina which is about growing raspberries in the home garden: http://www.ces.ncsu.edu/depts/hort/hil/hil-8204.html
QUESTION: Can you tell me something about the tree called the “Fringe Tree?” RA
JORDI: The Fringetree (Chionanthus virginicus L.) or “Old Man’s Beard” is native to north and central Florida. For more than a century, this little tree has been a favorite for home gardens. As one of the latest of spring-flowering trees and shrubs, it is a desirable ornamental to follow the maples, dogwoods, and redbuds. Its mature height is approximately 25 feet with a trunk growing to 8 inches in diameter, although it grows slowly. Large fringe-like white flowers appear in the spring when new petal growth appears. In addition, white, narrow, ribbon-like petals, which are slightly fragrant, will droop in clusters from 4-6 inches long. Dark blue or black olive-like fruit droops in clusters and ripens in the summer. The fruit does not attract birds but is not a significant litter problem.
The Fringetree wants to produce several trunks but can be trained by proper pruning to grow a single trunk. It grows in a variety of light conditions but does better if protected from harsh afternoon sun. The Fringetree prefers moist, acid soils but can grow in damp or slightly dry areas. This tree is truly a beautiful and under utilized tree. For more specific information about this tree check out this University of Florida website: http://hort.ifas.ufl.edu/trees/CHIVIRA.pdf
QUESTION: I have a Cassia shrub which produced beautiful yellow flowers in the fall. After our recent cold snap, the plant has died. Is it totally dead or will it grow back in the spring? BC
JORDI: More than likely your shrub will regrow and bloom those bright, showy, yellow flowers in October or November. The Cassia or Senna shrubs are considered part of the legume or pea family. A few of them are considered invasive such are the Senna or Cassia bicapsularis and the Senna or Cassia pendula, though you may have a different cultivar in your home landscape. The invasive types have been known to spread in Florida’s natural areas and they can be a nuisance in Central and South Florida because they grow year-round and produce an abundance of seed. Cassia is also known as Butterfly Bush or Christmas Senna, which was a native of tropical America. It can reach a height of 12 feet, grows rapidly, prefers full sun and can tolerate a variety of soil types. Cassia is classified as only marginally salt tolerant. Cassia can be susceptible to attack by caterpillars which destroy new growth and flower buds and twig borers can be a problem. Wait to prune it in late winter or early spring after the threat of freezing temperatures has passed.
QUESTION: Can I plant my Christmas cactus outside? KL
JORDI: Christmas cactus is in the genus, Schlumbergera, and in Northeast Florida it is most often treated as a house plant rather than a choice for the landscape. Of course, people are always surprising me and therefore in some micro-climates it may do well. However, before you plant it in the ground consider it would be at risk should we have a hard freeze. It is possible to cover the Christmas cactus until the threat of freeze is over, but may not guarantee success. If it is too large for your house, you might consider propagating it into smaller hanging pots. Propagation is easily done by leaves or cuttings. All parts of the plant are poisonous – so don’t eat it. But it might also be wise to keep it away from any nibbling animal friends or children. Christmas cactus can tolerate sun to partial shade and most of the time the reason this plant fails is the result of over watering. Err on the side of “too dry” to avoid root rots. Be cautious when hanging plants in windows; few of them like the intense heat caused by direct sunlight through glass panes. Filtered light through trees works best for most house plants.
Rebecca L. Jordi
University of Florida/IFAS
Nassau County Extension
Environmental Horticulture Agent III
543350 U. S. Highway #1
Callahan, FL 32011
(904)548-1116 or (904)879-1019