|Q. I lost two loquat trees near a pond. I want to plant a mahogany tree there now. Should I use potting soil, peat and cow manure around the tree? A. It is usually recommended to plant mahogany in the existing soil without improving it. It’s an adaptable tree and should do well. Make sure no chlorinated pond water leaks out as it can weaken or kill a tree or other plantings. Q. Our builder planted schefflera trees 6 feet from our buildings. They grew as tall as the buildings in 5 years and the association had them chopped back to 5 feet, eliminating shade. Now the association wants to remove them completely. They claim the roots will damage foundations and the sprinkler systems. What do you advise? A. I agree with the association completely. Scheffleras have extremely invasive roots that puncture and clog plumbing, lift and crack sidewalks and paving and have the potential to damage foundations. They also can start life in the tops of palms, gutters and tile roofs and drop down aerial roots to envelop the host plant and kill it. The only thing worse is ficus, which does the same damage but is bigger and can be more destructive. Q. We planted some strangler fig trees, cleared away the growth around them and they are growing well. Do you have any suggestions? A. Native strangler fig trees make good shade but have very aggressive roots that can destroy plumbing, paving and pools. I would put a barrier between the trees and whatever you wish to protect.
|Q. What is a good shade tree to buy? I can’t find any nurseries that sell trees. A. Many nurseries sell trees. To find one near you, check the display ads in the Yellow Pages under “Nurseries.” Mahoganies and gumbo limbos make good shade trees. Shade trees bring many benefits such as noise suppression, pollution reduction and lowered energy costs because of a temperature drop of 10 degrees or more under the tree on a sunny day. Q. Can you give me the name of a small shade tree that grows from 15 to 25 feet high? A. If you have an open lawn area the carrotwood is a good choice. It is one of our more trouble-free plants in south Florida. It makes a neat, small shade tree for smaller yards or townhouses. It is neat and doesn’t drop too many leaves, but it does drop seedlings that can sprout in the landscape beds. This is more of a problem in the western mucky soil areas, especially west of State Road 7. When used on a lawn, the seedlings will be mowed before they can sprout. Carrotwood does not like a lot of water. Many of the western county areas have poor drainage. If you live in that area, I would make sure it is not planted in a low area with standing water or water that drains off slowly. Watch your watering schhedules. Remembering to water only in the mornings between 2 a.m. and 10 a.m. and only if necessary. Another good small tree is the `Lakeview’ orange jessamine. The tree is tough with fragrant white flowers and small red fruit. It can be pruned to 15 to 20 feet. Some of the smaller palms _ solitaire or tall veitchias _ are also good choices. Q. I need a recommendation for a shade tree that does not grow more than 20-30 feet, has a noninvasive root system and is not messy. It needs to be near the house as the property is narrow and fenced. Where could I purchase the tree? A. A number of native plants would fit the bill, as well as some palms. The Dahoon holly will grow 20-30 feet and is narrow growing, so will not take up much space. It has noninvasive roots and is relatively neat. Green buttonwood is salt-tolerant and vertical growing in its youth. It can reach 30 feet with time. If you can’t find them in stock, local retail nurseries can order both trees.
|Some smaller, narrow-growing palms such as the Florida thatch, solitaire, carpentaria and foxtail will give decent shade with a narrow crown. All grow to 20-30 feet over time, with the carpentaria maxing out at 40 feet. The solitaire and thatch palms are available multi-stemmed, which can provide more shade. You can create your own clump by buying several palms of the same type at different heights and planting them together. Plant the smaller palms at an angle out from the central big vertical palm to give additional shade and add a tropical look to the landscape. Q. My Italian pines are turning brown. What can I use to stop this condition? A. The Italian pines are Italian cypress. They come from a dry climate around the Mediterranean coast which receives about 20 inches of rain a year. Our annual rainfall is 50-65 inches. The trees thrive in the dry California climate. Do not give them any water. Spray copper fungicide on the plants for Phomopsis twig blight. Follow label directions and retreat in 10 days. The only other possibility is spider mites. Spray with an insecticidal soap to control mites. Q. What bug is attacking my bald cypress trees at the tips? A. The little brown growths at the tips of your cypress trees are cones; they are perfectly natural and are the way cypress trees reproduce. Q. Will ginko trees do well in South Florida? A. We are too far south for ginkos to do well. Q. Can you identify my plant with the curled leaves? What should I do to control this problem? A. Your curly-leafed plant is a Ficus retusa, which should be removed because of its aggressive root system that can crack paving, plumbing and even pools. The curled leaves are caused by thrips. They can be controlled with a systemic insecticide such as Orthene.. The damage is just cosmetic and does not affect the tree adversely. Q. We have a Norfolk island pine that is too tall and needs to come down. If we cut it back will it still grow?
A.I would have the Norfolk Island pine cut flush with the ground. The pine is a conifer and will not re-sprout from the stump. Q. I have two 40-foot Norfolk island pines in my yard. Do the needles cause a soil problem? I can’t grow anything under them. A. Norfolk island pines drop large amounts of needles that create a layer that may bury small plants. Larger plantings should survive under the pines if the lower branches are cut to 7 feet off the ground. You might try crotons, compact jatropha, wild coffee, firebush, or other durable plants. Remember large-leafed crotons and wild coffee are prone to wilt and will require extra water. Q. We have two ficus trees near our property line with trunk diameters of about 2 ½ feet. They are about 45 feet from our home on a canal. Will they cause damage to our irrigation pipes or go to the canal for water. Should we remove some of the branches or cut the tree down? A. Wherever ficus roots go, they eventually cause trouble. The South Florida Water Management District might be interested in having them removed as a potential drainage hazard to their canals. The trees get huge and routinely blow over . Aggressive roots can plug plumbing, crack paving and pools, and even destroy building slabs. I have seen roots in third floor toilets. I would opt for removal if you can pull it off. Q. How do oak and other trees survive with cement or paving all around them and no place for water to reach them? A. Oak and other trees with roots under paving may be reaching an underground water source but are not getting nutrients so eventually will decline. Q. My laurel oak has not had many leaves on it for the past two years and the leaves that are there are spotted. What is wrong? A. Your laurel oak has some fungal leaf spotting. Laurel oak is difficult to establish because many landscapers install them too deeply in the ground. The trunk should flare out where it enters the ground. If the trunk goes straight into the ground, it is too deep. Trees planted too deeply cannot get enough oxygen to the roots, and the trees die back and have few leaves. Dig down with a trowel to where the trunk flares out and remove all the excess soil from above the original root ball so the the roots can breathe. The tree should recover if it hasn’t been buried too long. Spray with copper fungicide for leaf spotting.
Q. The tree bark on my pigeon plum has started to peel with long vertical cuts in several places. What can we do? A Pigeon plums normally have peeling bark. If the vertical cracks are superficial I would not worry about it. Deep cracks can be caused by major tree stress like drought, excess water, etc. Q. I was considering planting a tree in my yard like the one I saw growing on a corner of U.S.1 and SE 10th Street in Deerfield Beach. I went back later in the year and saw that it drops these big messy pods so I decided not to plant it. What kind of tree is it? A. The tree you saw is a bischofia female in fruit. The fruit stains and can eat away paint. One of my clients lived in a condo and his parking space was under a female bischofia. The fruit ate away at the car’s vinyl roof and ruined the paint. The adjacent condo would not cut the tree so his condo cut the tree vertically; the end result was half a tree. These trees also have invasive roots and are, as you say, messy. They often get oleander scale, which covers the leaves with white dots and causes excessive leaf drop. The seedlings appear in flower beds and the tree has the potential to become invasive. I’m glad you don’t want to plant one. Q. I have enclosed a leaf from a tree that just began growing in my yard. A bird probably dropped a seed. Can you tell me what it is and if I should I keep it? A. The leaf that you sent to me is from the ear-leaf acacia tree. This is a very fast growing tree that is now naturalizing in south Florida. The tree is pretty, but messy and very brittle. I would probably discard it unless you have a lot of room for a brittle tree. Ear-leaf acacia is joining a long list of exotics that are finding Florida to their liking. The “invaders” include the big bad three: Brazilian pepper (aka. Florida holly), casuarina and melaleuca. Newer invaders include bischofia, poinciana, woman’s tongue, lead tree, Ficus nitida, schefflera, and many others. * *An added note for those with access to the Internet: · The proliferation of exotic plants has had a profound impact on Florida’s eco-system. View the EEPC List of Florida’s Most Invasive Species and learn to make informed choices for your landscape that will reduce invasive plants and protect the plants that are endangered. http://www.fleppc.org/97list.htm· Also recommended: Plant Invaders: How Non-native Species Invade & Degrade Natural Areas – by John Randall on the Brooklyn Botanic Garden web site. http://www.bbg.org/index.htmlQ. Will a Florida red maple do well if planted where I live, which is near I-95 in West Palm Beach? A. Florida red maple is a beautiful native tree adapted to wet areas in Florida. If the tree is planted in areas that are excessively dry, the leaves will scorch and exhibit brown areas. This is also true if the tree is located in excessively windy areas such as near the beach. I would mulch the tree with wood chips about 1-2 inches deep for moisture retention. Keep the bark about one to two inches away from the trunk so the bark can breathe. Fertilize in March, June and October with a 7-3-7 fertilizer containing manganese and iron to promote good growth. Q. My black olive is losing its leaves and its roots are coming up.. We sprayed it but the leaves continue to fall. It also has a gash in the trunk. Should I put tar over the wound? A. Black olive trees lose leaves usually in the spring months between March and May as the new seasons growth begins. These trees are normally quite healthy and vigorous in south Florida. Manganese problems have occurred in some areas because of high pH. A good 6-6-6- or 7-3-7 fertilizer with the minor elements of manganese and iron can be applied in March, June and October. The tree may have split or peeling bark if it is in a wet area or receiving too much water. Water the tree no more than once a week if there is no rain. Loose bark should be removed. The wound area would heal more quickly if its in the shape of a football, pointed at the top and bottom. No tar or paint should be used on the tree. I am curious what the tree was sprayed with. Do not spray randomly for the sake of doing something, but only if a serious localized condition exists. Black olive roots are shallow by nature so some will appear at the surface. You could cover the root area with 1-1 ½ inches of light sandy soil and plant ground cover under the tree. Groundcover examples include artillery fern, oyster plant, Boston fern, etc. Grass will not be able to grow successfully under older black olives unless branches are lifted to let in sidelight.
|Q. Our condo board has planted a black olive tree in our yard and its branches will be over my parking area. Will the leaves that drop off stain the white vinyl top on my car? A. The black olive is a good shade tree, growing to 60 feet in height and 40-50 feet across. The tree is not good in parking lots as the leaves contain tannic acid, which can stain. This is a problem in condominiums where parking locations are permanently assigned. A permanent car cover or a new parking spot could be possible alternatives for you. Perhaps your spot could be used for guest parking. Q. We have 30-foot laurel oaks at our condo that are beautiful but we want to limit their size. Is there a growth retardant that will help us to control the growth? The tree has too many leaves and we seem to be raking a lot. A. Your laurel oaks are still young trees at 30 feet tall. These trees can reach 60-70 feet in height and have a spread of 50 feet or more. Laurel oak is native to South Florida and is a beautiful, generally trouble free plant, although they tend to transplant poorly. The tree is semi-deciduous, losing most of its leaves over an extended period between December and March. Growth retardant work has been researched to some degree in California, but not on laurel oak to my knowledge. Arborists and electric utility companies are very interested in growth retardants to reduce the pruning work necessary around power lines. These materials can act erratically in climates such as ours, which are very hot and humid. The University of Florida in Gainesville is working in conjunction with Chevron Corporation to develop a material to retard tree growth. The material is injected into the trunk of the tree and slows down the growth. A tall groundcover of fishtail, Boston fern, or macho fern may be useful to minimize the raking problem. The leaves sift through the ferns to the ground and reduce the work load. Acorns probably wouldn’t germinate if the fern bed is thick enough.
|Q. We purchased our property because of the large stand of pine trees. Now someone is building a house and a pool nearby and our trees are beginning to look like they are dying. What is happening? A. Slash pines are among the most sensitive of our native plants to any type of disturbance. Almost all slash pines near construction of any type will die within 7-10 years. Many die before that. Slash pines die from root compaction caused by heavy equipment or changes in grade or water table. Buyers of lots with slash pines often face a triple whammy. First they pay a premium for the “wooded lot”, then they pay again to remove all the dying pines. They pay a third time for replacement trees. Golf courses suffer from this problem too. The slash pines cannot tolerate the daily watering they receive on many golf courses. Your best defense is to keep your pine trees healthy. Fertilize themn with a 7-3-7 fertilizer containing manganese and iron in March, June and October. Water the fertilizer in. Try half heads on your sprinkler system so the pine trees are not normally irrigated artificially except at fertilizing time. Q. My pigeon plum leaves are dry and rust-colored. The tree bark has started to peel with long vertical cuts in several places. What can I do? A. Pigeon plums normally have peeling bark. If the vertical cracks are superficial, I would not worry about it. Deep cracks can be caused by major tree stress such as drought or excess water. The leaf problem appears to be from a leaf miner. Try Orthene for control, following label directions exactly. I have noted many deaths recently on weeping podocarpus from root rot, and fungal problems causing death from the top down. A.&I. Southern Agricultural Laboratories tested samples on a dying weeping podocarpus and determined the trees had Macrophoma and Gloeosporium fungal dieback which caused sap oozing and death to branches at the top of the tree. The tree in question was watered 3 times a week. The owner was going to plant waterpig impatiens near the tree which would have hastened its death. Capping sprinkler heads and a soil drench and foliage spray of Clearys 3336 or Medallion is recomended for control.