Oak wilt is a fungal disease that affects the water conducting system of red, white and live oak trees. This disease was discovered in 1961 in Dallas but wasn’t diagnosed definitively until the 80’s. It had the potential to be the most destructive disease in the US but has been most devastating in the state of Texas. We are just past the worst time to prune oak trees, February to June. Wounds can be an entry point for the sap eating beetle. You can paint the branches you prune with even an inexpensive latex spray paint. Oak roots can clone an overlay another root system so this disease can spread as far as 200 yards away. The veins of the leaf turn orange so this is you first indication that the sease is present and this disease spreads and kills the tree quickly so preventing it from spreading to other oaks is most important. Removing and burning the tree is best as heat kills the fungus. Texasoakwilt.org is a good website to learn more.
Texas A & M AgriLIfe has a handbook that lists all the diseases including many funguses of different species of trees in Texas. Your local agriculture extension office is a good source to help you diagnose the problem. You can send them a picture or take in a sample.
When you decide to plant a tree you should do your homework and consider the mature size of the tree and the crown and if it will fit in your landscape and if it thrives in the Houston climate and zone. A benefit in this hot climate is for the tree to provide shade. Fruit producing trees can be nice for they can be messy and some, for instance cherry will not grow here as it doesn’t get cold enough for them to produce fruit.
It might be beneficial to learn what are the worst trees to plant. Starting with fruit trees–the Bradford Pear has beautiful flowers in the spring but they smell like rotting fish. The structure is weak and leaves debris whenever there is wind and the trunk is susceptible to cracking. If it is in your yard for some reason grass does not grow under this tree. A Mulberry has an aggressive root system and will come up everywhere in your yard and will even try to come up under your driveway or sidewalk causing cracks. Other negatives are the male trees produce a tremendous amount of pollen and they are prone to insects. Besides being a weedy tree, the Hackberry shares the same problem of attracting insects especially woolly aphids and also has an invasive root system. Many new home builders choose a Japanese Blueberry because they grow quickly but are prone to soot a black powdery airborne fungus that cannot be treated.
An exotic tree that was brought to the US in 1745 from China is the Mimosa. They have pretty pink flowers for a few weeks in the spring but the rest of the year it has big brown seed pods that are messy and can spread quickly. A popular tree in Houston is the Ash. It grows quickly but will be a worry during hurricane season as it is brittle. Also they are susceptible to the emerald ash borer that dcam from Asia. They have not been a problem yet in Houston but are in the Northeastern part of Texas so will inevitably spread. Another non native invasive tree from China is the Chinese pistache that became very popular in North Texas but once mature the female produces a red fruit that turns blue. The birds like them and spread them everywhere. Although the tree is beautiful with bright red or yellow fall foliage it is now on the official state and national invasive species list. Good native choices are the prairie flameleaf sumac and the bigtooth maple. And even though there are many of them already, the Texas red oak is also an excellent tree.
The best time to plant trees in Houston is anytime from the beginning of Fall to the end of February, so there is time for them to establish their root system before the heat of summer and monsoons set in. Whether picking a deciduous, citrus or flowering tree it is important that there is enough room for the roots and mature size of the tree. Research the potential size in the climate you are in and the amount of sun a species will need to decide on the best spot for your new addition.
A new flowering tree would be a welcome splash of color in your landscape this Spring. Here are a few showy and hardy ornamental trees that will work well in Houston A tree that is a true Southern beauty is a Magnolia. The stunning large white fragrant blooms last for six months and the leaves are waxy and evergreen. Little Gem will be a great choice for a smaller landscape. Make sure of the variety because some there can grow to 70 feet tall.
Crepe Myrtle is another variety that is synonymous with the South. It can come in a variety of colors. Pick a sunny spot for this tree where you can enjoy the flowers that last from Summer into Fall, known as the flowering tree of 100 days. The leaves are red in the fall and there is an attractive outer bark that peels off to reveal pink inner bark so there is year round interest. This tree does need proper pruning in the winter to control size and form.
Another long blooming tree is a Desert Willow or Chilopsis and there is a pink or purple variety. Although it is a very low maintenance and fast growing tree it needs to be in an area that gets good drainage. As its name suggests it can withstand the heat of the Texas summer. The long leaf is shaped like the willow but it is not part of the Willow family. The flower is orchid like and it is multi stemmed growing more like a large bush. This tree is actually in the Catalpa family.
The tree that is one of the earliest to bloom is the Texas Redbud. Their vibrant magenta flowers certainly makes it stand out. This tree a graceful shape reaching only 20 ft at maturity. They can withstand drought and thrive even in alkaline soil. The leaf is heart shaped and it produces a 4” long seed pod that stays on the tree all winter.
Mulch around a newly planted tree is it’s best friend with these benefits listed by the Arbor Day Foundation.
Mulching provides so many benefits -most important of all is a fast growing tree. Research has proven that by placing a 3-6 foot natural mulch ring around your tree can double the growth rate.
Remove all grass that will compete for the trees water supply. The mulch should be 2-4 inches deep and not directly touching the bark. The ring should be like bagel with a 3-6 inch hole in middle. More is not better, although you can see examples of how not to mulch in your neighborhood. This results in reduced oxygen to the soil and will slow growth or result in death of the tree. The mulch will slowly be reduced as weather decomposes and wind blows it away so this is a yearly maintenance item in your yard. The best mulch is organic wood chips so choose the one that fits your taste and budget.
Native species of plants in Texas provide habitat for 632 of 914 birds found in North America providing cover, nesting sites and food. One native oak can support 500 species of caterpillars while you will find only 5 varieties can be found on an Asian variety. One pair of chickadees needs 6000-9000 caterpillars to raise a single clutch so you can understand why it is paramount to our ecosystem to plant native and not exotic. Urban landscapes are filled with exotic plants, buildings, hardscape and exotic plants. Texas A & M Forest lists 15 species of native oak trees that are found in the State so if you have room for this large tree in your landscape it will be bird-friendly and a joy to watch.
Some species of birds feed on the acorns-scrub jay, magpies, wood ducks, wild turkeys, mountain quail, flickers and woodpeckers. Many other insects that thrive on oak trees are food for many others including warblers, tanagers, vireos and orioles. The canopy of an oak, between 40 and 80 feet, has very strong branches, large leaves and drops leaves later than most deciduous trees and also this tree is incredibly hardy resistant to disease and insects. Spanish moss often grows in the branches and can be home to the Northern Parula that seeks this for nesting. Even dead oak trees can be home to barn owls and wood ducks that nest in their cavities. An oak tree is truly and community of living organisms that support many species of birds.
Summer storm and hurricane season is upon us and it is a time to give some attention to your valuable trees. Tree root cells need oxygen and after an extended period of time like 7 days the tree may experience root rot and soil around the tree may be washed away further making the tree unstable. There are some preventative measures you can take to improve the trees health and alleviate some damage. Mulch around the tree and keep the tree trimmed and the canopy pruned to allow more air movement. Stake or re-stake unstable trees and add nutrients such as slow release nitrogen. Warning signs that a tree has sustained flood damage are wilting or discolored leaves or premature fall colors, structural damage and exposed roots and pest infestation.
Other injuries to your trees can be avoided by paying attention to the trees critical root zone. This is an area equal to 1 foot radius from the base for each 1 inch of the tree’s diameter at chest height. If disturbance of this area cannot be avoided like trenching for utilities or irrigation the work should be done under the supervision of a certified arborist.
You should avoid the following situations around your trees:
–Changing soil grade or compacting soil with any heavy objects, vehicles or equipment
–Sounding trunks with weed eaters or mowers
–Attaching anything to the tree using nails
–Causing injury by fire or excessive heat
–Contaminating the soil
–Installing anything cement near the tree
Tree can give you pleasure for decades so they deserve your attention.
Cladoptosis is the naturally occurring shedding of branches of a tree. The tree may do this as a reaction to drought, soil compaction or disease. The branch that comes off will have a rounded ball and socket look. Specialized cells form where a break occurs. This is a protective layer that minimizes moisture loss. This will tell you that the tree is self pruning and not a large concern but to reduce the amount of limb drop increase watering and fertilization and reduce soil compaction in root area. Larches, pines, poplars, willows, maples, walnut, ashes, bald cypress, and oaks, shedding of branches is normal, often occurring annually in the fall, similar to the shedding of leaves from deciduous trees.
If the branch does not have this smooth looking break inspect the tree for visible defects and signs of insects. You should seek and arborist as soon as possible as other branches may come down. Different species are susceptible to various diseases and insects so professional advise is key in the correct treatment. Summer branch drop is common in older trees and in species such as oak, elm and ash. Correctly trimming a tree can prevent this hazard. Prune out damaged and low growth branches and those with decay or cavities. On mature trees have the long horizontal branches lightened and shortened and thin out the canopy.
If your tree has invasive rotting at the base of the tree it is called “butt rot”. The trunk of the tree is like the stem on a flower. If the stem gets broken it is not good. This condition may occur without you even noticing. There might be a shelf of fruiting bodies or mushrooms which you didn’t realize can indicate this problem. Unfortunately there is nothing you can once this is discovered as it has probably has been harming the tree for years, wood decay works from the inside out. Cutting the rotten wood out leaves the tree more vulnerable to disease because the tree can’t heal damaged tissue they will try seal them off and continue to grow. Painting the tree with wound dressing does not close wounds. A certified arborist could be called to see how extensive the damage is. If the tree is at risk of falling on a house or on people it may need to be removed.
If the tree is stable it would be good properly fertilize,water and prune the tree. A healthy tree could heal over the wound as it naturally grows new wood.Try to protect the tree from further damage. Lawn mowers or other vehicles may have damaged the tree. You can put mulch and maybe a rock ring in a large area around the tree and keep out other competing plants and grasses that need to be trimmed or weed-whacked. The tree can be wounded with the mower blade or string and this is where pathogen can invade.
Do you want to move a tree that is not where you want in your landscape design, or you purchased a new tree and are ready to plant it?
Here are some simple tree transplanting tips aimed at reducing stress on the tree and rapid root growth:
It may be prohibitive to plant or move a large tree and will give your landscape an immediate impact or planting several trees can be time consuming and labor intensive project. Consider hiring a professional to insure the job is done correctly and for the life and health of the tree. A warranty will protect your investment. Costs to plant your tree generally depend on the caliper of the tree (trunk size measured six inches above the root ball).
When you’ve planted a new tree, it’s important to protect it from the harsh elements of winter. Before winter comes, it’s a good idea to wrap your trees with a plastic tree guard or burlap, depending on the type of tree. Evergreens benefit the most from wrapped in burlap, while thin barked trees, like maples and sycamores, do best with plastic tree wrap.
Trees with thin bark should be wrapped to protect them from sunscald. Sunscald occurs in winter when the sun warms the tree’s bark. When the sun disappears, the temperature drops rapidly, causing the bark to dry and crack. Evergreen trees can get sunscald, too, when their needles turn brown.
You should wrap your tree in burlap or plastic if:
Once spring has sprung, it’s time to remove the wrap. Leaving the tree wrap on too long can be an invitation for pests, disease, and serious damage to your tree. Typically, it’s best to leave the wrap up from November until April. If the last winter frost has hit, it’s safe to remove the wrap around your tree, even if it’s not April yet. Use new wraps each season to protect your tree.
While wrapping your trees in the winter is important, it’s also important to make sure to remove the wrap in a timely manner.