Iron chlorosis in Utah landscape plants
Apr 28, 2026, 1:00 PM
Due to alkaline pH levels in the soil, plants may develop chlorosis, where leaves turn yellow while the veins remain green. (Taun Beddes)
(Taun Beddes)
Some trees grown in our area are not fully adapted to local conditions. One common challenge they face is our alkaline soil.
Soil pH strongly influences nutrient availability because it affects the solubility of nutrients in water, and plants can only absorb nutrients in dissolved form. Most plants grow best in a slightly acidic to neutral soil pH range of about 6.0 to 7.0.
However, many Utah soils contain significant amounts of calcium carbonate, sometimes up to one-third of the soil, which results in a higher pH, typically around 7.5 to 8.0.
At these alkaline pH levels, certain micronutrients, particularly iron and manganese (and to a lesser extent magnesium), become less available to plants. These nutrients are essential for key plant functions, including chlorophyll production and photosynthesis. As a result, plants may develop chlorosis, where leaves turn yellow while the veins remain green (a pattern known as interveinal chlorosis).
Susceptible Plants
Due to consumer demand, many plant species that are susceptible to iron chlorosis are commonly sold in our region. These include trees such as Autumn Blaze® maple, sugar maple, red maple, silver maple, red oak, as well as peaches and other stone fruits, raspberries, strawberries, and various ornamental landscape plants. Because many property owners purchase these plants without realizing their sensitivity to alkaline soils, managing chlorosis can be challenging.
Contributing Factors
- Soil texture (sand, loam, or clay), where chlorosis is more common in clay soil.
- Soil drainage
- Irrigation practices
Management Practices
If you have susceptible plants, allow the soil to moderately dry between irrigations by watering deeply and less frequently, rather than applying light, frequent irrigations.
Even with proper watering, plants may still require supplemental iron. Many iron products are available, but in high-pH soils, only chelated iron products containing EDDHA (or similar forms such as EDDHMA) remain effective because they stay soluble under alkaline conditions. Common products include Miller Feriplus, Grow More EDDHA Chelated Iron, and Sprint® 138.
Application Timing and Method
Chelated iron products are most effective when applied in early spring, typically between mid-March and early May. Apply the material evenly beneath the entire canopy of the tree or plant.
Current best practice is to mix the recommended amount of product in water (for example, in a 5-gallon bucket) and slowly apply the solution to the soil surface. Distribute it evenly in a spiderweb pattern beneath the canopy, with particular attention to the dripline, where most active roots are located.
Long-Term Solutions
Plants and trees often require annual treatment, and over time, this can become expensive—especially for larger trees. To reduce long-term maintenance costs, consider selecting species that are better adapted to alkaline soils.
Recommended alternatives for shade trees include:
- Pacific Sunset® maple
- Norwegian Sunset® maple
- State Street® maple
- Hedge maple
- Zelkova
- Hybrid elms
- White oak species (English oak, white oak, swamp white oak, and the native Gambel oak)
Additional Resources
Utah State University Extension offers several fact sheets on iron chlorosis with additional information and management recommendations.
