How to give trees iron

Preventing and Treating Iron Chlorosis in Trees and Shrubs | Forestry


As noted above, go to What is Iron Chlorosis and What Causes It? for more information on what iron chlorosis is and its causes. Briefly, iron chlorosis is a yellowing of plant leaves caused by iron deficiency, usually in high pH soils (pH above 7.0). Other causes of yellowing need to be ruled out first, however. For example, leaf yellowing can be due to insect or disease problems (pathogenic diseases caused by fungi or other organisms), herbicide misuse, or a history of over watering. Some tree cultivars have even been developed to have yellow foliage on purpose -- an example is the 'Sunburst' honeylocust (Gleditsia triacanthos var. inermis 'Sunburst').

If you have looked for these other problems and still suspect iron chlorosis, have your soil tested to see if the pH is above 7.0 to 7.5. If pH is high and you have ruled out other problems then iron deficiency is likely. Leaves with iron chlorosis will develop a yellow color with a network of dark green veins. In severe chlorosis even the veins may turn yellow or the leaf may even turn white. The outer edges also may scorch and turn brown as the cells die. Chlorosis can show an a few leaves, an individual branch, half of the crown, or the entire tree. Not all plants in a landscape will be affected.

Though iron deficiency is more likely, high soil pH also can cause manganese deficiency with similar looking chlorosis. Though a soil test may be helpful in ruling out such problems, often treatment for suspected iron chlorosis ultimately ends up ruling out other problems.

In the west soil pH tends to be highest where precipitation is the lowest. Therefore, look for iron chlorosis to be worse at low elevations away from the mountains.

Iron Chlorosis Prevention

Control of iron chlorosis is not easy and can be expensive, so prevention is better than treatment. Select plant species and cultivars that are tolerant of high soil pH and less likely to be affected by low iron availability. Table 1 describes the susceptibility of common landscape plants to iron chlorosis (some non-woody plants are included there as well). Avoid planting highly susceptible selections in Utah and other places with high soil pH, since recurring chlorosis will weaken the plants, predisposing them to other problems and/or shortening their life span.

Popular trees in Utah and throughout the interior West that have serious iron chlorosis problems and should be avoided in high pH soils are silver maple (Acer saccharinum) and quaking aspen (Populus tremuloides). Even though aspen is a native, it is native to higher elevation, cooler, wetter sites in the mountains with lower soil pHs. It is not well adapted to low elevation sites where it is typically planted.

Even trees that do well on soils with a moderately high pH, like Norway maple (Acer platanoides) and Scotch or Scots pine (Pinus sylvestris), can show chlorosis on especially bad sites. If such trees start to show chlorosis, the problem tends to get worse over the years as carbonates build up in the soil from irrigation.

If a tree is young and constantly chlorotic consider removing it and planting a better-adpated species. But what should be done about large, established, valuable trees that are exhibiting chlorosis symptoms?

Plant culture is also important in the control of iron chlorosis. Avoid saturated soil conditions by reducing watering or by installing drainage, especially with susceptible trees and shrubs. Aerate compacted areas around the base of affected vegetation. Also, avoid using plastic sheeting as a mulch for susceptible plants, since it restricts oxygen movement into the soil. High soil phosphorus also can make iron chlorosis worse.

Iron Chlorosis Treatment

Several methods are available for treating iron deficiency. These are: 1) soil application of elemental sulfur combined with ferrous (iron) sulfate; 2) soil application of iron chelates; 3) foliar sprays containing ferrous sulfate or chelated iron; or 4) trunk injection of ferric ammonium citrate or iron sulfate (trees only). Foliar treatments produce a rapid but incomplete response, while a soil or trunk treatment will last longer. Soil treatments require considerable work, but generally do not injure trees and can be more economical. Table 2 lists some advantages and disadvantages of different iron chlorosis control methods. Often, one method will work well in one area but not in another due to variations in soil conditions and species susceptibility. Try different methods until you find the one that works in your situation.

Soil treatment

Use soil applications to treat individual trees and shrubs, or small areas in a landscape, in the fall or early spring. A mixture of equal parts iron (ferrous) sulfate (Table 2) and elemental sulfur can produce lasting results and is relatively inexpensive. Select an inorganic iron source with a high concentration of iron and one that is derived from iron or ferrous sulfate. Read labels to determine iron concentrations and forms in different products.

It is not practical or desirable to blanket an entire landscape with the elemental sulfur-ferrous sulfate combination. Instead, treat small areas by making holes 1 to 2 inches in diameter and 12 to 18 inches deep. Space the holes 18 to 24 inches apart around the area within the drip line (outer edge of crown) of affected trees and shrubs. Fill each hole with the iron sulfate-elemental sulfur mixture to within 4 inches of the soil surface. Table 3 provides recommendations for the number of holes and quantity of the ferrous sulfate-elemental sulfur mixture required to treat plants according to their size. Make holes with an auger or soil probe that removes soil to reduce compaction. Avoid damaging large, woody roots when making holes. Also, check with local utility companies if making holes in the vicinity of underground utility lines.

Areas of small shrubs in a garden also can be treated with equal parts ferrous sulfate and elemental sulfur. Use a hoe to excavate a small trench approximately 4 inches deep, 12 to 24 inches away from the base of plants. Apply one inch of the ferrous sulfate-elemental sulfur combination to the bottom of the trench and then fill in the remainder of the trench with soil.

Over time, the concentrated sulfur in the holes or trenches reacts to form acid which neutralizes lime and lowers soil pH in a small zone around the treated areas. The acidification of soil in combination with the iron sulfate maintains iron in a form that can be absorbed by plants as roots grow into the treated areas. One soil treatment with iron sulfate-elemental sulfur may last 2 to 4 years depending on conditions.

Some iron chelates can be used as a soil treatment; however, the effect is temporary (one year) and chelates are relatively expensive. Check label instructions for application guidelines. The only chelate that works well under high pH soil conditions is one containing the FeEDDHA molecule (Table 2). All other chelates currently on the market are ineffective at pH greater than 7.2 and therefore are not very effective as soil treatments in much of Utah.

Use chelates in spring before growth begins. Sprinkle dry chelate on the soil surface and irrigate in, or dissolve in water and apply to soil around the base of plants. Chelates can also be applied in holes around the drip line of affected vegetation.

Foliar treatment

Foliar applications are made directly on the leaves of affected plants during the growing season. These treatments produce a quick response, often in a matter of days. Response to foliar sprays, however, is often incomplete (spotty control) and temporary. Repeated applications of foliar sprays may be required if chlorosis symptoms persist or as new foliage appears. Foliar sprays are difficult to apply to large trees.

Iron chelates (Table 2) are quite effective as foliar sprays. Follow label recommendations that come with these products. A 0.5% solution of ferrous sulfate applied to foliage also provides some control and is less expensive. A 0.5% solution is formulated by dissolving 2 ounces of ferrous sulfate (20 to 22% iron) in 3 gallons of water. Foliage should be sprayed in the evening or on a cool, cloudy day to prevent leaf burning. Add a few drops of liquid soap or wetting agent (available at farm supply stores) to help the solution adhere to the leaves. Repeated applications of foliar sprays may be needed if chlorosis symptoms persist or as new foliage appears.

Trunk injection or implantation

Iron compounds in dry or liquid form can be placed directly into holes drilled into a tree's lower trunk. Systems also are available that use plastic tubing and tees, capsules of various types, or a hypodermic-like tool to place iron materials into the tree. Though these techniques can be quite effective, they injure the tree's trunk and should be used with care. Minimize injury by using methods and formulations that require small holes (some systems use holes as small as 1/8 inch diameter), and avoid any treatment that would require injecting a tree more than once every few years.

Commercial injection formulations are available as liquids or powders and should be used according to directions. Look for formulations that contain ferric ammonium citrate (iron citrate) or ferrous sulfate. Holes should be made with a sharp brad-point bit to ensure quick uptake and reduce injury. Pay particular attention to manufacturer recommendations on hole placement, angle, depth, and diameter. Studies have shown that uptake is better and more evenly distributed if holes are drilled near the soil surface on the outside of root flares. Covering or capping holes can be done for cosmetic reasons, but will not reduce the chance for decay or speed healing. Wound dressings should not be used.

Injection treatments generally are most effective if applied in the early spring during bud break, but follow label directions for particular products. Treatments later in the year often will not be as effective and may not last as long. Effects can be expected to last for two or more years, after which retreatment probably will be necessary. Avoid injecting materials on hot, dry, windy days since leaves may blacken or burn, though such damage is usually temporary and not serious. Make sure the tree is well-watered for several days before and several weeks after injection treatments.

Product Availability

Ferrous sulfate, iron chelate and elemental sulfur products can be purchased at larger garden supply stores or agricultural chemical dealers. Chemicals and apparatus for injecting or implanting trees can be found at, or may be ordered by, some nurseries and garden centers.

Iron Deficiency in Trees is Easy to Treat - Tree Care | Arbor Aesthetics Blog - Arbor Aesthetics Tree Service - Professional Tree Trimming & Tree Removal




We're getting into late summer and iron chlorosis is rearing its ugly head for many trees in the Omaha area. This is a common disease in Eastern Nebraska that is easy to treat and cost effective if you plan on keeping your tree long term. Chlorosis is fatal if left untreated for multiple seasons. Don't delay addressing this issue! If you have a relatively young tree that is continually chlorotic, consider replacing it with a different species.


50 Shades of Green - Symptoms of Chlorosis

In the early to mid-summer, you may notice your leaves turning an abnormal color like yellow or light green. This discoloration may occur on your whole tree, or just sections of the canopy. Look closely at the leaves and you'll spot green veins, like in this photo. In advanced stages of disease, leaves will begin to turn brown and fall off, and limbs will begin to die back. 

What Causes Iron Chlorosis?

Generally, Nebraska's soils are alkaline (pH above 7). While our soil contains plenty of iron and manganese, the alkalinity makes the nutrients insoluble and unavailable to trees. Merely adding iron to the soil may not improve the condition of the tree. The problem can be further compounded by low oxygen conditions which are common in poorly drained soils or soil that has been compacted due to heavy foot traffic or construction.

Chlorotic red maple.

What species are most susceptible?

Very common:

  • Pin oak
  • Silver maple
  • Red maple and hybrids (Red Sunset, Autumn Blaze, etc)
  • River Birch

Less common:

  • Cottonwood
  • Swamp white oak
  • Bald cypress
  • Ornamental juniper
  • Eastern white pine

Is Iron Deficiency Fatal?

Yes - iron deficiency kills trees. Trees need iron to manufacture chlorophyll. When a tree lacks chlorophyll, it can't produce adequate energy via photosynthesis and the tree will begin to decline. 

A tree in decline is also more susceptible to other diseases and insects. 

Advanced stages of iron chlorosis.

Can I Prevent it? How do I treat it?

There are many methods of treating iron chlorosis, with some being more effective than others:

  • Water during dry spells, but don't overwater. Believe it or not - overwatering can CAUSE iron deficiency!
  • Mulch to improve soil conditions, but keep it under 2" deep and don't pile it against the trunk. No mulch volcanoes!
  • Don't fertilize. Excess nitrogen or phosphate can cause a tree to become chlorotic. Keep lawn fertilizers away from trees. Again, mulching under a tree instead of growing grass is a good solution.
  • Soil additives: You can amend the soil under the tree in a variety of methods. However, the tree may not respond to these methods until the following season, and research shows this method is ineffective especially for larger trees. Remember: Nebraska soil is rich in iron; the high pH makes it unavailable to trees.
  • Avoid planting susceptible species in alkaline and/or poorly drained soil. 

The outer cells of these leaves are dying due to advanced chlorosis.

Our Treatment Method

Arbor Aesthetics uses a macro injection system to flush iron (and/or manganese, depending on the species) directly through your tree's vascular system via injection sites at the root flare. These treatments are performed in the fall and can provide up to three years of green, happy leaves for your tree! 



its application, instructions for use


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For normal growth, plants need nutrition rich in useful elements. One of these is iron chelate - an indispensable microfertilizer for plants in a biologically active form. Among Ukrainian manufacturers, the leading company for the production of chelated fertilizers and directly their first developer is the SPC "REAKOM".

Features of the use of iron chelate for plants

There are three possible ways to use iron chelate: root tillage, drip irrigation, and foliar plant nutrition. It is the foliar method of applying microfertilizers with iron in the composition that gives the best result.

In use, iron chelate shows a number of positive qualities:

  1. Non-toxic.
  2. Completely soluble in water and easily penetrates foliage.
  3. Compatible with mineral fertilizers and pesticides.
  4. Universal in application.

The effect of regular use of iron chelate is expressed as follows:

  • Elimination of iron deficiency.
  • Emergence of immunity to diseases in plants.
  • Improvement of photosynthesis and plant respiration.
  • Normalization of metabolism.
  • Stimulation of plant growth and development.
  • Ensuring sufficient availability of chlorophyll in the leaves.

Instructions for use of iron chelate for plants

The proportions, time intervals and duration of use of iron chelate depend on the purpose for which the drug is chosen: prophylactic or therapeutic.


Feeding plants with iron chelate will not be superfluous if the plant does not have any visible signs of disease.

In this case, measure out 5 g of iron chelate and dissolve it in 10 liters of water. Processing with the prepared solution is carried out once every 2 weeks by spraying the foliage throughout the entire vegetative period. You can start preventive treatment from the moment the first leaves appear, and you need to finish before flowering. During this time, spraying should be carried out at least 2 times at a consumption rate of 1 liter per 10 square meters. m.

In the treatment of chlorosis

Chlorosis, caused by iron deficiency, manifests itself in plants in the form of the following symptoms:

  • yellowing of the leaf blade with the appearance of green veins;
  • reduction in leaf size;
  • shoot retardation;
  • causeless fall of leaves, flowers and buds;
  • inflorescence deformity;
  • curling the sheet at the edges.

If at least one of the listed symptoms of a disease is detected in a plant, it needs treatment.

For this purpose, it is necessary to dilute 5 g of the drug in 5 liters of water (for fruit trees) and 8 liters of water (for all other types of crops). The foliage is sprayed with the resulting solution every 2 weeks at least 4 times for the entire cycle. With pronounced chlorosis, the effect can be enhanced by root application of iron chelate, for which 5 g of the drug is diluted in 5 liters of water. at the rate of 2 liters per 1 sq. meter.

When working with iron chelate, it is important to observe safety rules: spray with gloves, goggles and a gauze bandage. And if the solution gets on the skin or in the eyes, they should be washed with water.


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Suspended foliar fertilizer

Soil acidity and its effect on plant nutrition

Nitrogen is the 4th most important plant nutrient

Growing seedlings: rules for soil and seed preparation, top dressing and planting

Fertilizers for trees: when, how and what to apply

You can get a high yield from fruit trees, create a unique alley of coniferous plants only with the right top dressing. In the land without fertilizers, there are not enough nutrients for full growth and fruiting. In addition, there are no trace elements that increase resistance to viral, microbial and fungal diseases. Consider which fertilizer for a tree to choose. When and how to submit it.

Fertilizing purposes for trees

The productivity and beauty of plants in the garden directly depends on the type of soil. Fertile soil can not be fed during the first years of the plant's life. In central Russia, in particular in the Moscow region, more than 70% of the plots have unproductive soddy-podzolic land. And it requires constant fertilization in order for the plant to develop properly, form new shoots, ovaries and fruits.

General objectives for tree fertilization:

  • Activation of plant growth, increasing the quality and quantity of fruits.
  • Improving the immunity of trees, protection from pests and diseases.
  • Nutrition of roots, trunks and foliage with essential microelements and minerals.
  • Replenishment of useful substances in the soil.
  • Reducing the acidity of the soil, if necessary.
  • Acceleration of growth of coniferous and deciduous trees.

Top dressing is carried out according to the seasons: in spring, autumn, during the growing season, less often during fruiting. In addition to fertilizing, caring for garden trees includes cleaning fallen leaves, dried branches, crown formation, sawing off diseased branches and additional protection, treatment for diseases.

Seasonality of fertilizing

Active period of adding microelements to the soil: autumn, when trees are deficient in phosphorus and potassium, and in spring, when the juice begins to flow along trunks, branches, buds swell. In the spring, they feed the earth twice: when the plant awakens and after 3 weeks.

What kind of fertilizer trees need depends on their type, soil composition and natural disasters. For fruit plants most often contribute:

  • In the spring ammonium nitrate with urea.
  • At the end of flowering - complex granular fertilizers.
  • During fruiting, formulations without nitrogen to delay ripening.
  • Potassium and phosphorus in autumn.

Consider the type of plant. So, it is better for apple and pear trees to make organic matter with a minimum amount of nitrogen compounds. The best option for the second spring bait is 1.5 cups of ash infusion with 30 g of ammophoska per square meter. meter. Make the solution into the wells along with watering.

What fertilizers do apple, cherry, pear trees need

Apple and pear trees are similar in terms of growth stages, structure and fruiting time. Both trees do not like an excess of nitrogen agents. The following fertilizers will be useful for them:

  • The first spring dressing should replenish the supply of phosphorus and potassium.
  • The second, 2-3 weeks after the first, includes organics: 1.5 cups of infusion on ashes and 30 g of ammofoska. This is enough for 1 m² of area. Watered under the root.
  • At the end of spring, copper and boron are replenished. You can mix 2 g of copper sulfate with 0.5 g of boric acid per 10 liters of water. This is enough to water 1 mature tree or 2 young plants.
  • After harvesting the fruits, replenish the supply of potassium. To do this, water with a solution of potassium monophosphate in the amount of 10-15 g per 10 liters of water.
  • Once every three years, after fruiting, apply 30 g of double superphosphate per square meter around the trunk.

Trunks are whitewashed in autumn. It protects against sudden changes in temperature, infections and raids of wild animals. The same procedure should be carried out in the spring to protect against sunburn. To prepare the mixture, you can take 2.5 kg of freshly slaked lime, 300 g of copper sulfate or 500 g of iron sulfate. Pour all this into 10 liters of water and add 100 g of whitewash to them.

Care for cherries and cherries is slightly different from apple and pear. What fertilizer does this tree need?

  • In June and July they feed 2-3 more times with an interval of 3 weeks. They also add organic matter. With chicken manure, proportions must be strictly observed so as not to damage the roots.
  • Nitrogen fertilizers can be applied from early spring to mid-summer. Late feeding is not needed. It will delay the preparation of the tree for winter. Trace elements are introduced in the spring. Suitable urea, ammonium nitrate, potassium salt, superphosphate. The amount and frequency of top dressing depends on the age of the tree and the type of soil.

    Fertilizer for coniferous plants

    Perennial evergreen trees also need care. But they don't need as many nutrients as fruit plants. We need microelements for a set of cell mass and for building greenery.

    Fertilizers for coniferous trees are also applied seasonally:

    • Mineral mixtures with magnesium are applied in spring. It is close in structure to chlorophyll and is needed for the photosynthesis of needles. Suitable dolomite flour in the amount of 0.5-1 kg per tree.
    • In early spring, young shoots can be fed with calcium. But a small amount. Combined fertilizers are chosen, where the composition contains a small amount of easily digestible calcium.
    • Add fertilizer with sulfur and iron. Potassium humate, combined fertilizers for coniferous plants are suitable.
    • Fertilize with potassium in the summer to prepare the plant for winter.

    The best feeding option for conifers is to apply granular micronutrients to the soil around the trunk. They gradually nourish the soil and the plant.

    Additional feeding

    A tree can get the necessary trace elements and minerals through injections. The nutrient solution is injected directly under the bark. "Injections" are arranged so that the plant itself gradually absorbs the substances contained in the container.

    Such fertilizers for fruit, coniferous trees are selected after biochemical analysis of the plant.

    Learn more