To the extent that soil conditions effect the general overall health and nutrition levels for trees, the answer is yes. The most important factors, however, are temperatures and moisture levels at the time prior to and during the color season. For example, above normal temperatures, especially at night, made this autumn a poor one for color throughout much of the Northeast. Trees stressed by drought during the growing season will not color well. In my experience, many tree species growing significantly outside their native range will also not color as well as they would in their home territory.

presuming they are deciduous ... we rule out prior winter damage ...

so we are down to what happens during the summer ... to figure out what effects the leaf when it basically dies ...

so i agree drought would be high on the list..

complicated by transplant .. until the plant is fully established.. which can take 1 to 3 years .. depending on.. wait for it.. drought.. lol ... or proper aftercare ...

if the color of the basic summer leaf is a proper green ... then i would suggest nutrients are not the issue ... but a soil test sure wouldnt hurt.. or at a minimum.. at least a call to the county soil conservation or Ag office.. they usually have off the cuff answers to soil issues in your immediate county ...

when it comes to trees ... fall color is very low on my list of concerns ... time and 'establishment' will come .. sooner or later .. and when that happens .. truer color will show ...

all that said.. fall leaf color is extremely variable.. year to year ... just like nut production .. or cone production ... they all ebb and flow

ken

There are some plants that the flower color is affected by the soil PH. Are there trees that react the same?

The effect of soil pH on fall color varies with the tree species, and with cultivar. I have seen it noted that October Glory Red Maple is much redder in acidic soils versus more alkaline soils. I have in fact seen this happen. However I do not know about Pistache. But I do know nutrient levels can have a significant impact on autumn colors. Trees in heavily fertilized lawns tend to stay green much long. Drought effects are variable and depends upon the intensity of the drought. Some trees will respond more brilliant color, early color, muted color, or just drop leaves. i.e. American Smoke Tree tends to produce brighter colors drier poor soil conditions. Also the amount of sunshine often has a large effect. More clear days helps color. In the case of Chinese Pistache, color is not so dependent upon cool weather, and too cool seems to mute it's colors. Too cool too early has muted a many of fall in my location as well. Lastly, it can take years for a newly planted tree to produce normal fall color. As a general rule, the larger the tree at planting, the longer before fall color resumes. Each of our Sugar Maples took 3-4 years, and they were 1-1.25" caliper trees. Our Milky Way Kousa dogwood has 4 years, and still is not behaving normally, though completely healthy otherwise. So in your particular case, I would bet your Pistache simply has not been there long enough. I've seen it stated that it takes 8-10 years before completely normal behavior of 2" caliper plantings, and longer for larger plantings. Proper planting is critical as well, and the most frequent mistake.

How big of a Pistache did you plant? What time of year did you plant? Is it planted properly? Did you plant it? How do you water? How much? How often? I would expect it to improvement over the next couple years, and keep the fertilizer away from it.

Arktrees

Certainly it's not hard to find information on what weather characteristics contribute to good fall coloring that year.

Years ago, I heard a professor of horticulture speculate as to certain reasons that a plant may or may not exhibit spectacular leaf color in the fall.

The specific plants in question were grafts of a Quercus x bicolor, grafted the same year by the same person, onto the same rootstock, planted at the same time; ie, identical in every way except in location of planting. One was planted on the university's main campus, in Fargo, ND, in the flood plain of the Red River, in a clay soil. the other was planted on a research farm near Absaraka, located outside of the flood plain on a loamy soil.

The tree in clay rarely colored, the tree in loam exhibited reliable color year after year.

Truth or speculation? Any grad students looking for research topics?

It seems to be highly variable from what I've observed in Dallas-Fort Worth area.

My guess... a combination of soil type and genetic.