What Is Going On?
Mountain laurel (Larrea tridentata) is a tree native to the southwestern United States. It grows from sea level to at least 10,000 feet elevation in the mountains. Its bark is smooth and grayish brown with light yellow stripes running through it. Leaves are oval or ovate, dark green above and pale green below, and grow up to 6 inches long and 1 inch wide. They have five leaflets each.
The trees produce small white flowers in clusters called rosettes, which are followed by tiny seeds. These seeds are very hard to see, but they look like little black dots and they’re found only on the seed heads. When these seeds germinate, they turn into tiny plants that don’t do anything except live out their lives.
There are two main types of disease affecting mountain laurel: soft rot and powdery mildew. Soft rot is caused by fungi and occurs when the fungus attacks the roots of the plant. The fungus will eat away at the root system until there isn’t enough room for new roots to grow, causing death. Powdery mildew is caused by bacteria that attack the leaves and stems of a tree.
This type of disease kills trees within one year after symptoms appear.
Soft rot appears first as a general yellowing of the leaves. Leaves will wilt and turn brown, whereas the veins will remain green. This is accompanied by a general wilting of the plant and roots that turn black at the point where they were connected to the tree. This type of disease is only recognized upon digging up the infected tree and seeing discoloration and fungal growth on or around the roots.
Powdery mildew causes a white or grayish growth on the surface of both the upper and lower sides of the leaves. It may also be accompanied by white patches on the stem. These patches are sometimes surrounded by a slightly darker area. The patches turn yellow, then brown, and eventually cause premature leaf drop.
Soft rot is caused by several different fungi that affect mountain laurel, and the improper use of pesticides may increase the risk of infection.
Powdery mildew is caused by a specific type of bacteria that is activated by sunlight and high temperatures.
There are no known cures for these diseases, so the best way to treat them is to prevent them from occurring in the first place. The following steps can help extend the life of your mountain laurel:
1. Keep the soil slightly dry.
This can be done by only watering the plant during the morning and making sure the soil is dry before nightfall.
2. Space plants far enough apart so they get plenty of air circulation.
3. Lay cardboard down under the plants to prevent the spread of disease and water in the morning rather than in the evening to allow the roots to dry out.
4. Pull up and remove all diseased plants and their roots as soon as you notice any disease symptoms.
5. Consider not planting mountain laurel in your area at all.
Unfortunately, once a plant starts showing symptoms of disease, there is very little that can be done to save it. While you can dig up and remove the infected plants, the disease will continue to spread to your other plants.
The main way to prevent these diseases is to not plant mountain laurel at all in your area. It just isn’t worth it.
Mountain laurel cannot tolerate shade, so if you want to plant it, make sure it gets plenty of sun. While mountain laurel can grow in a range of different soil types, it does best in well-draining sandy loam. Avoid planting mountain laurel in the same place every year and only buy plants from a reliable source.
There aren’t really any pests that will severely affect mountain laurel in your area. There are, however, some insects and rodents that tend to like mountain laurel just as much as you do.
Animals and rodents love to eat the leaves and flowers of mountain laurel. These pests must be dealt with if you want your plant to survive.
Powdery mildew can be spread by insects that love to eat diseased foliage. Keeping your laurel free of these types of insects will help prevent the spread of disease.
Animal and rodent pests:
Mountain laurel tends to be very appealing to a wide variety of animals and rodents. They love to snack on the leaves and flowers, completely unmindful of the fact that the plant is poisonous to them. The deer and rabbits tend to eat the foliage and contribute to its destruction, while rodents like to burrow under the soil and chew on the roots. Either way, your mountain laurel will not survive for very long if you have an overabundance of these pests.
There are many ways to deal with animals and rodents. You can use chemicals such as poisons and traps, or you can take a less harmful approach with fencing and certain plants that repel these types of pests.
Native American tribes used to incorporate mountain laurel into their culture. Some tribes used the berries as a substitute for food while others used them as medicine or added them to ceremonial rituals.
Tribes also incorporated the flowers into their everyday lives. They would sometimes be used to make necklaces or simply to make decorative designs. The leaves were sometimes used for ceremonial purposes as well, although not very often.
The wood of the mountain laurel tree was used rarely. Some tribes used it to make small articles such as bowls and other decorative pieces. It was not used for anything important since it had a tendency to rot quickly.
The mountain laurel has been used in many ways by many different people over the years. It is a beautiful plant that can be a joy to grow and take care of, but also a challenge due to its special needs. If you are careful and attentive however, the mountain laurel will always reward you with its lovely flowers every year and will brighten up any garden.
Other Interesting Facts
* Native Americans used the mountain laurel as a substitute for food. They made bread, pudding, and dumplings out of the berries.
* The bark and leaves can be used to make tea.
* Mountain laurel can be pruned into a hedge.
* In the 1700’s, mountain laurels were used in English gardens and landscapes.
Growing Mountain Laurel
Mountain laurel is fairly easy to grow, but it can only survive in a limited area. It can only survive in USDA hardiness zones 4 through 8. This area also needs to be at high altitude since mountain laurel cannot survive in an area that gets wet often.
It prefers well-drained soil that has a PH level between 6 and 7. The soil should be kept moist but not soggy.
The mountain laurel can grow in the full sunlight or in partial shade, but it needs protection from the hottest and brightest sunlight during the summer since it can cause the leaves to burn and turn brown.
Mountain laurel is a slow growing plant that only grows about a foot per year. It can grow up to 20 feet tall and 15 feet wide, but this will take many years.
If you need to transplant mountain laurel, it is best to do it in the spring or late fall since the plant hates to be moved and will take time to get used to its new environment.
The flowers bloom in the spring and are white with a purple center. The flowers are very delicate looking and have a strong, sweet smell.
When growing mountain laurel, it is important to remember that it is poisonous. It can be harmful or even fatal if eaten. When pruning or working around mountain laurel, it is important to make sure that none of the plant comes into contact with your skin and if you happen to get some on you, make sure to immediately wash it off.
It is also best to wear gloves while doing any work on or around the mountain laurel.
Common names include mountain laurel, broad-leaved laurel, shoemaker tree, and Southern mountain laurel.
Scientific name is Rhododendron Catawbiense.
Here is some more information about mountain laurel:
Mountain Laurel – A site all about the mountain laurel. It contains some history, facts, and pictures.
Mountain Laurel – This page has information about the mountain laurel as well as pictures and facts.
Mountain Laurel – More information about the mountain laurel including a description, pictures, and facts.
Mountain Laurel – Information about where the mountain laurel grows, its physical description, and some pictures.
Mountain Laurel – Some pictures of the mountain laurel.
National Forests – Learn about the plants and animals that live in the GSMNP.
Rhododendron – Information about the plant family that mountain laurel is a member of.
Trees – Learn about trees and see pictures of many types.
USDA Hardiness Zone Map – Find out what zone you are in.
Wildflowers and Trees – Learn about native wild flowers and trees.
Home – More free lessons on gardening and lots of other stuff.
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Soil – Find out what kind of soil you need.
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Compost – Perfect for your garden, flower beds, and lawn.
Garden Pictures – Lots of pictures of gardens, their designs, and layouts.
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Garden Tools – Find out which tools help you do the job the best.
Gardening Tool – Get all the tools you need for your garden.
Gardening Gloves – Protect your hands while working in your garden.
Shears – Cut your plants just right.
Trowel – Dig small holes for your plants.
Watering Can – Water your plants the old-fashioned way.
Weeder – Get rid of those pesky weeds.
Wheelbarrow – Move all that soil around easier.
Yardsticks – Measure to make sure everything is level.
Sources & references used in this article:
Mountain laurel and rhododendron as foods for the white tailed deer by EB Forbes, SI Bechdel – Ecology, 1931 – JSTOR
Origin, development, and impact of mountain laurel thickets on the mixed-oak forests of the central Appalachian Mountains, USA by PH Brose – Forest Ecology and Management, 2016 – Elsevier
Fuels on disturbed and undisturbed sites in the southern Appalachian Mountains, USA by TA Waldrop, L Brudnak… – Canadian Journal of …, 2007 – NRC Research Press
Effects of Fuel Reduction Treatments on Incidence of Phytophthora Species in Soil of a Southern Appalachian Mountain Forest by IM Meadows, DC Zwart, SN Jeffers… – … Disease, 2011 – Am Phytopath Society
Mountain Laurel: A Poisonous Plant… by AC Crawford – 1908 – books.google.com
How vegetation can influence regeneration by SB Horsley – Proc. of workshop on Guidelines for regenerating …, 1988 – fs.usda.gov
Applying hotspot detection methods in forestry: a case study of chestnut oak regeneration by S Fei – International Journal of Forestry Research, 2010 – hindawi.com