Magnolia Tree a Tradition

Magnolia Tree a Tradition

There is a tall stately tree that can be found throughout the southeastern states, native in nature with a lustrous green leaf the southern magnolia is like no other tree.  This amazing tree can be found from the edge of deep woodlands to the back of the tall sand dunes in the panhandle of Florida, all the way down the Florida Peninsula.  The leaves provide a consistent evergreen providing a year-round presence in the landscape.  Spring brings up small plate sized creamy white blooms with a wonderful fragrance with multiple blooms opening over 3 to 5 weeks. The magnolia can serve as a specimen tree or a back drop to allow other plants to be enjoyed.

Magnolia Tree in the Landscape. Photo courtesy Stephen Greer

Often the magnolia is envisioned to be this 80-foot tall by 40-foot-wide tree with an upright pyramidal shape with the branches reaching to the ground and up to 8-inch-long shiny green leaves.  There are other shapes and sizes in the landscape industry that have been found in many different ways from seedling research that has taken place at several of our land grant universities including the University of Florida.  Other magnolia with different growth and bloom habits have been found growing in nature.  Below are a few of these exceptional species that were selected by the keen eye of a nurseryman or a plant specialist.  Next come decades of field grown observation to determine if the plant characteristics are consistent with cuttings taken and rooted to grow more trees.  This is one way to see if the same look and growth continues in multiple plants.

Magnolia Bloom in Spring

Magnolia Bloom. Photo courtesy Stephen Greer

If you grow trees from collected seeds, the new seedlings will show variable growth patterns and likely not present a consistent growth or leaf form from tree to tree.  This is the reason for taking cuttings from a magnolia with the desired growth habit, leaf size and color, bloom color and fragrance.

Several cultivars have risen to the top in popularity in the landscape industry over the last 30 to 40 years.  One of the most popular large magnolias is ‘Bracken’s Brown Beauty’.  It was selected in a seedling field when one of the universities had completed research and invited a local nurseryman to come take any he wanted before the field was turned under for other plant research.  Many were dug and field planted at the nursery with one showing many desired characteristics.  With its dark rusty brown lower leaf and deep green top.  It was observed for a number of years with cuttings taken.  One major observation was its tolerance to cold weather.  They had a winner and began to introduce it into the plant industry.  ‘Little Gem’ is another magnolia that is quite popular for its dwarf (slower) upright growth habit.  It first was considered a hedge plant with a dense leaf canopy from bottom to top.  The challenge is the plant density opens up as it matures with it ultimately reaching approximately 30-foot tall by 20-foot wide.  The surprising part of this smaller magnolia is its bloom is similar in number, yet 3 to 5 inches in size in large numbers as the other southern magnolias.  Next there is a few weeks rest period and then sporadically blooms all summer and early fall.  There are so many magnolias that could be mentioned I just don’t have enough article space, so it will stop with ‘Claudia Wannamaker’.  This magnolia is an old stand by that has been found to be moderately salt tolerant and can be found growing near coastal settings.  The leaf wax layer is slightly thicker allowing for a little more protection from the salt.  It has a more open multi-truck growth allowing for wind to pass through more easily.  The challenge is finding one in the landscape industry.

Contact your UF IFAS Extension office in your county with questions.  Enjoy this wonderfully unique tree.

 

 

 

Magnolia Tree Buzzing with Insects?

Magnolia Tree Buzzing with Insects?

Do you notice a large number of bees or wasps visiting your magnolia  tree?  Do you see “bumps on the twigs”?  Are the leaves and branches turning black?  It is probably Magnolia or Tuliptree scale.

Large yellowish bumps on stem of plant

Photo by: Rebecca Bolestra

These scale belongs to a group of insects referred to as soft scales.  Scale insects feed by inserting their piercing-sucking mouthpart into the plant’s vascular system and removing sugar and water from the tissue.  As the insects feed the fluids become concentrated in the gut of the scale, forcing them to excrete a clear, sticky liquid called honeydew.  The honeydew drips onto the leaves, stems and anything else below.  Honeydew serves as a growth media for sooty mold, the thin layer of black fungus that forms on the surface.  The honeydew is a food source for other insects, like bees and wasps.  But, the sooty mold prevents sunlight from reaching the leaf surface, preventing photosynthesis from occurring.

Scales are identified by their body covering.  Magnolia scale (Neolecanium cornuparum) is one of the largest soft scale, measuring up to ½ inch in diameter.  They range from pink-orange to dark brown in color and are often covered with a white wax at maturity. Tuliptree scale (Toumeyella liriodendri) is a similar appearing scale that can infest magnolia species.  But, it does not form the white wax.

Magnolia and Tuliptree scale reaches maturity in August with one generation per year.  The female lays her eggs, which hatch internally and form crawlers that move from under the body covering and migrate to the underside of small twigs, where they will spend the winter.  Once settled in, the young scales begin to feed and never move again, growing larger in the same spot.

Now is the time to take action.  For small trees, the scales can be removed by hand with a soft brush.  Horticultural oil will smother adults and crawlers, if the trees to be treated are larger or time is limited.  Systemic insecticides can be applied for lasting effects.  Imidacloprid is a pesticide that can be applied as a soil-drench, reducing the potential for harm to pollinating insects.  In the fall, insecticidal soap can be applied to control the crawlers that hatched.  Plan on treating the tree again next year.  Scale population suppression usually requires at least two years of pest management.  For more information on scale insect management go to: https://edis.ifas.ufl.edu/pdffiles/MG/MG00500.pdf

Post Hurricane Landscape Care:  Replant Smartly with Hurricane Resistant Trees

Post Hurricane Landscape Care: Replant Smartly with Hurricane Resistant Trees

After a devastating windstorm, as we just experienced in the Panhandle with Hurricane Michael, people have a tendency to become unenamored with landscape trees.  It is easy to see why when homes are halved by massive, broken pine trees; pecan trunks have split and splayed, covering entire lawns; wide-spreading elms were entirely uprooted, leaving a crater in the yard.  However, in these times, I would caution you not to rush to judgement, cut and remove all trees from your landscape.  On the contrary, I’d encourage you, once the cleanup is over and damaged trees rehabilitated or disposed of, to get out and replant your landscape with quality, wind-resistant trees.

First, it’s helpful to take a step back and remember why we plant and enjoy trees and the important role they play in our lives.  Beyond the commercial aspect of farmed timber, there are many reasons to be judicious with the chainsaw in the landscape and to plant anew where seemingly sturdy trees once stood.  For example, trees provide enormous service to homes and landscapes, from massive cooling effects to aesthetic appeal.  Take this thermal satellite image of Hurricane Michael’s path that simultaneously shows the devastation of a major hurricane and the role trees play in the environment.

Lightly shaded area showing higher ground temperatures from loss of vegetation.

In the lighter colored areas where the wind was strongest and catastrophic tree damage occurred, the ground temperatures are much higher than the unaffected areas.  Lack of plant life is entirely to blame.  Plants, especially trees, provide enormous shading effects on the ground that moderate ground temperatures and the process of transpiration releases water vapor, cooling the ambient air.  Trees also lend natural beauty to neighborhood settings.  There is a reason people termed the hardest hit areas by Michael “hellscapes”, “warzones”, etc.  Those descriptions imply a lack of vegetation due to harsh conditions.  In this respect, trees soften the landscape with their foliage colors and textures, create architecture with their height and shape, and screen people from noise, unpleasant sights and harsh heat.

Though all trees give us the benefits outlined above, research conducted by the University of Florida over a span of ten major hurricanes, from Andrew to Katrina, shows that some trees are far more resistant to wind than others and fare much better in hurricanes.  In North Florida, the trees that most consistently survived hurricanes with the least amount of structural damage were Live Oaks, Cypresses, Crape Myrtle, American Holly, Southern Magnolia, Red Maple, Black Gum, Sycamore, Cabbage Palm and a smattering of small landscape trees like Dogwood, Fringe Tree, Persimmons, and Vitex.  If one thinks about these trees’ growth habits, broad resistance to disease/decay, and native range, that they are storm survivors comes as no surprise.  Consider Live Oak.  This species originated along the coastal plain of the Southeastern United States and have endured hurricanes here for several millennia.  Possessing unusually strong wood, they have also developed the ability to shed the majority of their leaves at the onset of storms.  This defense mechanism leaves a bare appearance in the aftermath but allows the tree to mostly avoid the “umbrella” effect other wide crowned trees experience during storms and retain the ability to bounce back quickly.  Consider another resistant species, Bald Cypress.  In addition to having a strong, straight trunk and dense root system, the leaves of Bald Cypress are fine and featherlike.  This leaf structure prevents wind from catching in the crown.  Each of the other listed species possess similar unique features that allow them to survive hurricanes and recover much more quickly than other, less adapted species.

Laurel Oak split from weak branching structure.

However, many widely grown native trees and exotic species simply do not hold up well in tropical cyclones and other wind events.  Pine species, despite being native to the Coastal South, are very susceptible to storm damage.  The combination of high winds and beating rains loosens the soil around roots, adds tremendous water weight to the crown high off the ground, and puts the long, slender trunks under immense pressure.  That combination proves deadly during a major hurricane as trees either uproot or break at weak points along the trunk.  In addition to pines, other widely grown native species (such as Pecan, Laurel Oak and Water Oak) and exotic species (such as Chinese Elm) perform poorly in storms.  Just as the trees that survive storms well possess similar features, so do these poor performers.  We’ve already mentioned why pines and hurricanes don’t mix well.  Pecan, Laurel Oak, and Water Oak tend to have weak branch angles and break up structurally in wind events.  The broad spreading, heavy canopy of trees like Chinese Elm cause them to uproot and topple over.  It would be advisable when replanting the landscape, to steer clear of these species or at least site them a good distance from important structures.

This piece is not a warning to condemn planting trees in the landscape; rather it is a template to guide you when selecting trees to replant.  Many of our deepest memories involve trees, whether you first climbed one in your grandparent’s yard, fished under one around a farm pond, or carved your initials into one in the forest.  Don’t become frustrated after a once in a lifetime storm and refuse to replant your landscape or your forest and deprive your children of those experiences.  As sage investor Warren Buffett once wisely said, “Someone is sitting in the shade today because someone planted a tree a long time ago.”

For these and other recommendations about how to “hurricane-proof” your landscape, contact your local UF/IFAS Extension Office.  Plant a tree today.

Algal Leaf Spot Common on Magnolias and Camellias

Algal Leaf Spot Common on Magnolias and Camellias

Algal leaf spot, also known as green scurf, is commonly found on thick-leaved, evergreen trees and shrubs such as magnolias and camellias.  It is in the genus Cephaleuros and happens to be one of the only plant parasitic algae found in the United States.  Although commonly found on magnolias and camellias, algal leaf spot has a host range of more than 200 species including Indian hawthorn, holly, and even guava in tropical climates.  Algal leaf spot thrives in hot and humid conditions, so it can be found in the Florida Panhandle nearly year round and will be very prevalent after all the rain we’ve had lately.

Symptoms

Algal leaf spot is usually found on plant leaves, but it can also affect stems, branches, and fruit. The leaf spots are generally circular in shape with wavy or feathered edges and are raised from the leaf surface. The color of the spots ranges from light green to gray to brown.  In the summer, the spots will become more pronounced and reddish, spore-producing structures will develop. In severe cases, leaves will yellow and drop from the plant.

Algal Leaf Spot

Algal leaf spot on a camellia leaf. Photo Credit: University of Florida/IFAS Extension

The algae can move to the stems and branches in more extreme cases. The algae can infect the stems and branches by entering through a small crack or crevice in the bark. The bark in that area cracks as a canker forms that eventually can girdle the branch, killing it.

Algal Leaf Spot on a Stem

Algal leaf spot on a sycamore branch. (Platanus occidentalis). Photo Credit: Florida Division of Plant Industry Archive, Bugwood.org.

Management

In most cases, algal leaf spot is only an aesthetic issue. If only a few leaves are affected, then they can just be removed by hand.  \It is important that symptomatic leaves are discarded or composted offsite instead of being left in the mulched area around the trees or shrubs. If symptomatic leaves are left in the same general area then irrigation or rain water can splash the algal spores on healthy leaves and branches. Infected branches can also be removed and pruned.

Preventative measures are recommended for long-term management of algal leaf spot. Growing conditions can be improved by making sure that plants receive the recommended amount of sunlight, water, and fertilizer. Additionally, air circulation around affected plants can be increased by selectively pruning some branches and removing or thinning out nearby shrubs and trees. It is also important to avoid overhead irrigation whenever possible.

Fungicide application may be necessary in severe cases. Copper fungicides such as Southern Ag Liquid Copper Fungicide, Monterey Liqui-Cop Fungicide Concentrate, and Bonide Liquid Copper Fungicide are recommended. Copper may need to be sprayed every 2 weeks if wet conditions persist.

Algal leaf spot isn’t a major pathogen of shrubs and trees, but it can cause significant damage if left untreated. The first step to management is accurate identification of the problem.  If you have any uncertainty, feel free to contact your local Extension Office and ask for the Master Gardener Help Desk or your County Horticulture Agent.

The ‘Star’ of Magnolias

The ‘Star’ of Magnolias

Magnolias are well known plants to gardeners and many are familiar with the foliage and flowers of these plants. If you are looking for another earlier bloomer, you may want to consider adding a specimen selection to your landscape, the Star magnolia (Magnolia stellata).

 

Although not native to the United States, star magnolia is a slower growing multi stemmed deciduous shrub reaching about 15 feet in height over time. The best feature are the bright whitish pink star-shaped blooms appearing in late winter before leaves emerge.  The flowers offer gardeners a peek of the spring to come and remind us that our Gulf Coast winters are not that long. DSC_0065

Plants do best in soil with some organic amendments and mulch over the root systems. A planting area that receives a little afternoon shade is ideal but established plants will adapt to sunnier locations when irrigation is provided during drier weather.  Only occasional pruning is required to remove crossing branches or those that grow out of bounds.  Prune after flowering if needed.

Late-flowering Magnolias Avoid Freeze Damage

Late-flowering Magnolias Avoid Freeze Damage

‘Jon Jon’ magnolia

This winter’s recurring freezes and frosts have played havoc with early flowering plants like magnolia. While buds are freeze-resistant, open magnolia flowers can quickly turn brown after exposure to temperatures about 30°F or lower. One way to avoid freeze-damaged flowers is to choose later blooming cultivars. These selections have flowers that open in north Florida during late February or later.

 

The Magnolia Garden at the University of Florida/IFAS North Florida Research and Education Center (NFREC) in Quincy has more than 150 types of magnolias planted. Based on over 10 years of data, five of the latest blooming magnolias are Daybreak, Jane, Betty, Jon Jon and Ann. These cultivars have peak bloom dates ranging from late February (Ann) to mid-March (Daybreak). Thus, they bloom after most flower-damaging freezes.

 

Daybreak has beautiful, large shell-pink flowers on a small tree. Jon Jon has huge white flowers with a streak of red-purple at the base. These fragrant flowers open goblet-shaped the first day, and then open wider to a cup-and-saucer shape on subsequent days. At NFREC, Daybreak and Jon Jon have about 6 weeks of flowers and grow as single-stem or multi-stem trees up to about 30 feet tall.

 

Jane, Betty and Ann are sister cultivars developed at the National Arboretum. As you would expect with sisters, they look-alike, and have a shrubby or multi-stemmed tree habit, generally growing about 15 feet tall and wide (much shorter and wider than Daybreak and Jon Jon). All three have upright, cup-shaped flowers in various shades of pink and red-purple. Betty has medium red-purple flowers that are the largest of the three, over 4 inches. Jane has 3- to 4-inch flowers that are medium pink outside and white or pale pink inside. Ann has the smallest flowers (3 inches) but they are also the darkest red-purple. As an added bonus, Ann boasts the ability to produce sporadic flowers all summer long! This results in Ann having an average of 13 weeks of flowers, as compared to Jane’s 10 weeks and Betty’s 8 weeks.

 

These five cultivars are generally available at garden centers during spring. Ann and Jane can be found at many “Big Box” stores. All five can be purchased at “good” independent garden centers and, as a last resort, from mail-order/Internet nurseries.

 

For more information about these and other magnolias, see Florida Extension publication, ‘Jon Jon’ Magnolia: A Late-Flowering Deciduous Magnolia for Northern Florida, and other magnolia publications here. Also, Magnolia Society International is a great resource with a very informative website. (Note the slide show below of Jon Jon, Ann, Betty, Daybreak and Jane.)

 

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