Yard doc: Bottlebrush trees declining throughout South and central Florida
Q: We live in an HOA with 55 bottlebrush trees and they have large amounts of ball moss on them, I know that they say it will not kill the trees as it is an air plant and does not rob the trees of anything, but they have gotten so thick they are robbing the trees of light and water. Some trees are half-dead. Is there anything we can spray on the trees to kill the ball moss? We will lose all our trees and the city says replace a tree with the same thing. I don’t think the HOA can afford that expense. Help!
— Lou, Port St. Lucie
A: I sighed when I read Lou’s email. It is true, ball moss, Spanish moss, and air plants do not kill trees. These native bromeliads simply use the host plant for support. They are not parasites and have no way of invading a tree or shrub and feeding from the water, mineral nutrients, or products of photosynthesis from the support plant.
Yet, the myth of death by air plant persists. Air plants occur naturally, and the populations expand or decline with growing conditions. I have often called these epiphytes canaries in the coal mine; they are warning signs trouble is afoot. Like all plants, the things which encourage air plant/ball moss growth are sun, water, air, and nutrients. When a host tree or shrub begins to decline, it often drops foliage allowing more sun into the interior of the plant. More light and air movement mean more growth of air plants.
The decline of bottlebrush trees is a problem throughout central and South Florida. These trees tend to be short-lived, in part due to serious pest problems. Bottlebush plants are very susceptible to infestations of nematodes and witch’s broom. Nematodes are microscopic roundworms, which feed on the roots of plants and in the case of bottlebrushes, cause a slow decline and death.
Witch’s broom is a condition of deformities caused by several pests. Mites, viruses, fungi, mistletoe, insects, nematodes, or natural genetic changes have all been implicated in the formation of the deformities. However, here in Florida, the most common cause in woody, evergreen trees and shrubs is a fungal infection of sphaeropsis tumefaciens.
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There are no applied treatments which will cure infestations of either nematodes or witch’s broom. Good overall management practices, including proper irrigation, pruning, and nutrition help the plants tolerate the pests for a while. However, in the end, plants get old and no amount of pruning, fertilizer, water, or applications of pesticides or snake oil will make the plants live beyond their useful years. Shrubs and trees stressed by intense landscape maintenance or are susceptible to pest issues such as bottlebrush, hibiscus, Ixora, and oleander typically gives us 7 to 15 useful years in the landscape at most.
Many associations are dealing with aging landscapes. Why Associations don’t reserve for this high-ticket and life-cycle limited asset baffles me. However, planned replacement is the best choice. My recommendation is to hire a consultant, horticulturist, arborist, or other green professional to evaluate the trees and develop a plan and budget for replacement. Remember, trees are good and increase property values. The green professional can and should negotiate with local municipalities for a proper replacement plan which selects good plants; it is rare the same species should be used as replacements and a procedure to implement the replacement plan over several years.
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Carol Cloud Bailey is a landscape counselor and horticulturist. Send questions to carol@yard-doc.com or visit www.yard-doc.com for more information.