Pine trees can die months after a hurricane. Photo: Julie McConnell, U. Florida.

Dying Pine Trees

Recently, AHA observed some dead pine trees in the landscapes of home in DeRidder. Laurie call and asked about dead pine trees and wanted to know if there is a disease or insect killing her pine trees.

Since 1992, Mary L. Duryea and Eliana Kampf, researchers from the University of Florida, have studied the effects of hurricane winds on trees. One of the observations is the slow death of pine trees months after the original storm date. For example, research teams observed that 48% of standing longleaf pines in south Florida had died. This research found that trees can take up to two years to succumb to their storm damage.

Duryea and Kampf discuss the possible causes of this pine mortality, “The causes of yellowing of the needles and pine death are not completely understood. It is likely due to hidden damage produced by bending and twisting during hurricane-force winds. Prolonged winds may also rupture smaller roots without breaking the larger support roots. The injured stems and roots are unable then to supply the water and nutrients needed in the crown, resulting in pine decline and death.”

Even though a pine tree looks green, root damage can stress these trees. Duryea and Kampf make these recommendations:

• Monitor pines carefully. Sometimes there is hidden damage and the tree declines over time.
• Check closely for insects. Weakened pines may be more susceptible to beetles and diseases.

A crape myrtle in possible need of fertilization. Photo: Keith Hawkins, LSU AgCenter.

Yellowing Crape Myrtles

Ellis came by the AgCenter concerned about his crape myrtle trees. He observed yellowing of the leaves and asked for a site visit.

When AHA arrived to examine Ellis’ trees, the yellow leaves had fallen off. However, the foliage at the tops of the trees looked healthy. AHA suspects the lower yellow leaves lost nitrogen which went to the upper, actively growing leaves at the tops of the trees. Another factor may have been that the yellow leaves had fungal leafspot, the trees aborted those leaves.

On balance, Ellis’s trees are easily treatable with fertilization. A soil test will help with specific recommendations for application rates. Ellis can also treat his trees with a fungicidal soil drench to help with leafspots during these rainy days.

A leaf from a parasol tree, an invasive exotic tree. Photo: Susan Virden, Alexandria, LA.

Chinese Parasol Tree

Susan saw an interesting tree and asked for identification, “I was driving along Versailles Boulevard off Jackson Street [in Alexandria] and saw this tree with tiny white/ cream flowers on a stem in a bunch/ panicle with an astilbe shape that stuck out from these leaves as seen in the pictures are about 12 inches or a little bigger. The trunk was straight and smooth with a medium grayish color. Some were shorter about 15 feet, and some were taller than two stories of a condominium. They were maybe ten to fifteen foot wide at the bottom limbs with a cylindrical shape. They are beautiful. What are they?”

Susan saw a Chinese parasol tree (CPT), an exotic, invasive tree from China. “Invasive Plant Atlas of the United States” is a website developed by the University of Georgia, the United States Forest Service, and other agencies. Regarding CPT, this website states, “This plant is self-fertile which means it only takes one tree to produce fertile seeds. The prolific seed production along with its quick growth and aggressive competition make Firmiana simplex a candidate for EDRR - Early Detection & Rapid Response program in the warmer regions of the United States.”

An ailing palm tree. Photo: John Touchstone, homeowner.

Ailing Palm Tree

John has a palm tree and sends this email, “I have a palm tree with some issues. It was beautiful, healthy, and full before the freeze and hurricanes. Now, it seems to be struggling to survive. Ill attach pictures. I have owned this house for two years and never fertilized the tree. Even though I strapped it before the storms, it did shift somewhat in the ground. I just don’t know what to do to make sure I don’t lose it. I also don’t know the species. Anything you could do to help, even point me in the right direction, I would appreciate very much.

AHA shared these thoughts, “The tree looks like it survived the big freeze earlier this year. Also, let me encourage you to obtain a soil sampling kit from the LSU AgCenter and use it to send a soil sample to a lab in Baton Rouge. The results will provide recommendations on fertilizing. “

Hannah Wooten, a horticulturist with the University of Florida, made these comments in her blog:

• The first rule of palm fertilization is to fertilize for the palm, not the turfgrass.
• The second rule of palm fertilization is not about fertilizer at all. It is about pruning! If it is not dead, do not prune it off.
• Paraphrase: Correct the pH for the right range for palm trees.