Cure Yellowing Eucalyptus Tree

Q. I have a 20 plus year old eucalyptus tree. The leaves are very yellow. What is the cause of this?

Its not a simple answer when it comes to yellowing eucalyptus. Could be anything. Judging from the plants around it and recent water restrictions I am wondering if it is water related.

A. Yellowing leaves can mean many things. It could be a nutritional problem, watering issues, or damage from insects or disease. I need more information as well as leaf and tree pictures. Make sure it gets an iron application to the soil in the spring. To be on the safe side, apply an iron chelate such as EDDHA.

This is the iron chelate called iron EDDHA. Because of its chemistry it performs well in all soil pH if applied in the spring.

            Check for a watering issue or a leak that floods the soil in that area. Eucalyptus is “mesic” in their water use so an application frequency for large trees should be used. When water is applied it should be deep and wide or large shrubs that receive water should be located under its canopy. Once a tree is chosen its increasing water use as it gets bigger has also been chosen.

Will Green Light Chelate Cure Iron Chlorosis in Highly Alkaline Soils

Q. I used a product called Green Light. It contains chelated iron, copper and zinc for correcting plants that are yellow. Is this similar to the chelate you talk about for our soils?

Roses Growing Weaker After Installing Rock Mulch

Q. I have some well-established rose bushes (15 years) in our front yard. Five years ago we converted to desert landscape and the landscaper put about 3 inches of small rock in the area containing the roses. They seem to be healthy although the density and beauty of the blooms was weaker last year.

            I've been using liquid Miracle Gro. Is there a better liquid fertilizer, or should I consider pulling the rock away from the bases and fertilize through the soil. Thanks.

 

Not the readers rose but what can happen to roses over time growing in rock
mulch and little care.

A. Miracle Gro products are fine but I would also add a separate iron fertilizer. Go to your local nursery and get a one pound canister of iron EDDHA. Follow the label directions but I find it more effective to mix in a teaspoon of the product in a gallon of water and water it into the rootzone of each plant.

Some of the Miracle Gro specialty fertilizers. Actually any of these would interchangeable. Miracle Gro might disagree
but these labels are mostly to help novice gardeners select a fertilizer for specific plants.

            Each rose should get maybe one teaspoon January – March, a once a year feeding. Although best applied early, an application will work now. They should be all right if you keep it on this fertilizer schedule. Select a product that has a big middle number. There are several different ones to pick from and I don’t know their product line off the top of my head.

This is the correct iron chelate to use in our high pH soils.

            Feed roses about every two months lightly starting January – October. However the iron is needed just once a year. Do not neglect soil improvement as well by using composts and organic mulches that decompose into the soil. Roses will really appreciate wood mulch much more than rock mulch.

Pink Leaves on Purple Plum Probably Iron Problem

Iron chlorosis on purple leaf plum

Q. I have two red leaf plum trees both about two years old. They started the year beautifully. One continues to look normal but the other one has all of a sudden taken a turn that bothers me. The leaves are getting pale, pink instead of red and see through-ish. It is a nice full tree yet young. Is it as simple as not enough water or something else? It had a great year last year.


A. It is most likely iron chlorosis. If you want to see if that is the problem try making a few liquid applications of an iron chelate to some leaves using a spray bottle to see if this turns them dark purple (I am assuming you have a purple leaf plum).

            It may take four or five applications with a spray bottle to the same few leaves a couple of days apart since liquid applications to the leaves are not typically as effective as applying it to the soil. Otherwise buy some iron chelate containing the EDDHA chelate and apply it to the soil in a bucket of water and wash it in around the roots.

            You should see it turn dark purple in growth that comes out AFTER you make the application to the soil. This discoloration is also possible if the tree roots are being kept too wet by watering too often or you have poor drainage.