Tag chinese pistache

While North Texas is full of natural beauty, the changing color of leaves in the fall is not generally seen. More often than not, our trees are green for most of the year, and then drop their leaves quickly once real winter hits. However, there are a few common North Texas trees that do show some fall color, and there are also a few places close by in Texas that you can visit to get your fill of colorful fall leaves.

Why do leaves change color in the fall?

While we think of leaves as being green, in reality they contain pigments of many different colors, depending on the species. Yellow is one of the most common secondary pigments, along with orange. These colors are not usually seen, however, because the amount of green in the leaf, provided by chlorophyll, greatly eclipses the amount of other colors. The green-colored chlorophyll is an essential part of the plant’s ability to absorb sunlight and convert it into usable energy. During the spring and summer, leaves eagerly process the ample amounts of sunlight and help the plant to grow.

As the year winds down, however, and the weather turns cooler, the amount of daylight lessens. This drop in light and temperature triggers a change in the leaves. The vast stores of chlorophyll in the leaves are no longer needed, and begin to break down. The strong green color begins to fade and be replaced by the underlying pigmentation, such as yellow or orange. Related chemical reactions in the leaves can also produce other colors, like reds or purples. A mixture of several different pigments can appear as brown.

What determines a tree’s fall color?

The exact color of leaves in the fall depends on several factors:

• Species

  • This has the biggest impact on fall color.
  • Oaks usually appear brown.
  • Some maples show red, yellow, or orange.
  • Dogwoods and sumacs can exhibit purple leaves under some conditions.

• Light

  • Depending on your latitude, the change in amount of light from summer to fall can vary greatly.
  • A tree’s physical placement can also affect its reaction to the light changes.

• Temperature

  • Low (but not freezing) temperatures over an extended period of time can help with the generation of certain pigments, like reds.
  • Early frosts can stop pigment from developing further.

• Rainfall

  • Excessively wet weather can dull fall colors.
  • Hot and dry summers can deplete a tree’s resources, affecting fall color production.

Why don’t we see fall color in DFW?

Unfortunately, the trees common to North Texas, combined with the climate, do not make for vibrant fall color.

• Oaks, one of the most common trees in DFW, generally show brown fall coloring.
  • Live oaks, however, are usually green through winter and drop brown leaves in the spring.
  • Red oaks can show their namesake-colored leaves in the fall, if they don’t drop their leaves early.
• Elms and other trees common to our urban forest do show some yellowing in the fall.
• While maples are known for their bright fall colors, they are not very common in North Texas, and when they are planted, are usually smaller than the oaks, pecans, and elms around them.
• Our dry summers and wet autumns usually make for muted fall coloring, and we generally have sudden, drastic temperature changes rather than slower cooling.

Are there any North Texas trees that show vibrant color?

While there are few native trees that exhibit fall color, a few imported species can do well here and give a better chance of a dramatic change.

• Chinese pistache (Pistacia chinensis) is a common sight in our urban forest, and, under the right conditions, can turn an earthy red color in the fall.
  • Be sure to plant the pistache where there is good drainage, or it may develop health issues.
  • Arborist Tip: Chinese pistaches are more likely to show fall color when both male and female (berry-producing) trees are present.
• The tallowtree (Triadica sebifera) is less common than the Chinese pistache, but can produce a variety of fall colors.
  • Be careful, though, as the tallowtree is not cold-hardy.
• Maples do not always do well in our climate and soil here, but if you can get one to become established, you have a great chance to see fall color.
  • The Japanese maple is a well-loved ornamental tree that can showcase beautiful colors. One variety has coral-colored bark, for a spark of color even when the leaves have fallen!
  • The most common color is red, but some species can show yellow or purple.

Where can I go to see fall color in Texas?

Although we may not have an impressive fall showing in North Texas, there are several places in Texas that do.

• Tyler State Park, just a short trip from DFW, is full of maples, dogwoods, and sweetgums that can show a variety of fall coloring.
• Lake Bob Sandlin, in East Texas near Pittsburg, also is known for its fall foliage.
• Check out this article for more suggestions!

At Texas Tree Surgeons, we love trees (whether they turn colors in the fall or not), and we love our customers! We are always happy to talk about planting possibilities to introduce color to your yard. While we can’t guarantee leaf change in the fall, we do have several great options for spring color! As always, let us know if you have any questions, are looking for planting recommendations, or want to know how best to take care of your trees!

Dear Texas Tree Surgeons,

My Chinese pistaches are looking terrible! The leaves are yellowing, the berries are black, and it looks like it’s dying. What’s going on?

-A.B.

For many years, the Chinese pistache (Pistacia chinensis) has been well-regarded as a landscape shade tree for urban environments in Texas. Although native to China, this species of pistache (related to the nut-bearing pistachio tree) can thrive in a variety of conditions. The Chinese pistache is a fast grower and is resistant to heat, drought, and alkaline soil, all common in North Texas. Like the native red oak, the Chinese pistache is a reliable source of fall color. The dark red berries that female Chinese pistaches produce are not only striking, but can attract birds and other wildlife. For many builders and landscapers, the Chinese pistache is a go-to choice.

This year, however, we have been seeing unprecedented dieback and wilting of leaves and berries in Chinese pistaches. Entire trees are exhibiting leaf spotting and extensive browning. Similar to the browning present in Italian cypresses the past two years, it seems that the Chinese pistache dieback is caused by a fungus. And much like the Italian cypress issues, there may not be much that can be done at this point.

Water, Water Everywhere

Recent wet weather, combined with poor drainage in clay soils, creates a “wet feet” situation in trees, where their roots are inundated with too much moisture. Trees that are not suited to wet soils are not able to regulate the high moisture level in their roots effectively. The roots then become susceptible to pests, especially fungi, which thrive in damp, poorly-drained soil. As the tree root tissue becomes waterlogged, the fungi are able to gain a foothold in the roots and begin infecting the tree internally. Eventually, the tree’s vascular system itself becomes the mechanism by which the fungal spores are spread throughout the branches, leaves, and fruit. The fungus disrupts cell function in the above-ground parts of the tree, just as it did in the roots.

What Can We Do About It?

Unfortunately, there is often little that can be done to improve overall drainage in clay soil. Still, there are some things that tree owners can do to give their trees the best chance:

• Select native species that are well-adjusted to the North Texas climate
• When planting, do not plant too deep, and follow good mulching practices
• For established trees, do not overplant the area near the root collar and inside the drip line with turf grass or other groundcover
• Consider root collar excavation (Airspading) for trees that were planted too deep
• Vertical mulching and soil aeration can help break up heavy clay and compacted ground
• Stop watering and turn off sprinkler systems during periods of heavy rain

Sometimes, despite best practices, fungal infections cannot be avoided. At the first signs of leaf spotting, or unseasonal browning or wilting, contact a certified arborist to diagnose any issues with your trees. Your arborist can suggest a plant health care program. Fungicidal treatments can be helpful, but must be timed appropriately. Once a tree shows extensive browning or dieback, it is often too late for fungicides to be effective.

If It’s Too Late…

If your trees are covered in dead berries and have dropped a lot of leaves already, it is unlikely that a fungicide would have much effect. The best thing to do would be to remove any diseased material from the tree, do as much as you can to improve drainage, and begin a fertilization program. With a good winter freeze, the fungus should die off. In the spring, reevaluate the tree for early signs of new or lingering fungal activity, and treat as appropriate.

At Texas Tree Surgeons, we love trees, and we hate to see a new problem arise that affects a common and much-relied-upon tree like the Chinese pistache. We have submitted samples to the Texas Plant Disease Diagnostic Lab and are awaiting the results. With proper identification, we may be able to better control the particular fungus in the future. We will be sure to let you know what we find out. Keep an eye on our Facebook page for updates!

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We received our results from Texas A&M. The samples we submitted from one Chinese pistache specimen showed evidence of both Phytophthera root rot and Anthracnose stress.

Phytophthera is a pathogen that causes damage to root tissue which can lead to the death of a tree. Phytophthera’s activity is enhanced by wet soil conditions and poor drainage. While fungicidal treatments can be applied, they will be of little benefit unless the underlying moisture and drainage issues are corrected.

Anthracnose is cause by a fungal pathogen, and can take advantage of plants that are already weakened by other stressors. The best method of managing anthracnose is to clean up and dispose of any fallen infected leaves or berries. Fungal sprays may be applied, but are generally not recommended during late summer or autumn, as the trees are preparing to go dormant for the winter, and the fungus should decline naturally.

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As always, please let us know if you have any tree questions. We are always happy to have a certified arborist come out and take a look a small issue to hopefully stop it from becoming a big problem!