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What's causing these two problems?

Posted by GreenDreamhome Zone 9 (My Page) on
Tue, Jun 10, 14 at 19:49

The first photo is of a leaf from one of my old, established roses. I don't know what kind it is (it came with the house.) What could be causing the drying of the leaves like this? The rose bush farther down on the same wall doesn't have that problem.

The second photo is from another my old, established rose in my back yard. Not all of the leaves are like this; just a particular patch up on top.

I'm in the Phoenix area where it's in the hundreds every day now.

Follow-Up Postings:

RE: What's causing these two problems?

Here's the second photo

RE: What's causing these two problems?

Hi GreenDreamHome: Perhaps the previous home-owner over-applied fertilizer to that rose. Some roses are more susceptible to salt-damage. Knock-outs can take salt-abuse, but certain roses can't.

The 1st picture looks like fertilizer burn. I got the same when I mixed 1/2 horse manure into the planting hole .. horse manure has high pH, plus 10% salt. No amount of rain could undo that, so I had to replace the soil.

Luckily the rose was small, so I could dig it up, rinsed the root-ball in a bucket of water, and planted in new soil.
Someone in Florida once posted similar pics of leaves with big brown spots .. she mixed 1/2 cow manure (alkaline & salty) with her sandy Florida soil.

I did that to my lawn recently .. there was left-over soluble acid-fertilizer 32-10-10, so I used a flour-duster to sprinkle on my lawn. I spilled a bit, so there's this big-brown-spot .. still there despite this rainy month.

The second picture looks like my Sharifa Asma when I over-dosed on molasses (high in iron). Same with last year when I gave Gina's rose soluble molasses without watering her first. The molasses-brown-spots are easy to fix: tons of watering, the Gina's rose was OK ... when I dug her up to give away, the roots was huge.

In hot climate, the soil tends to be more salty. I don't fertilize when the temp. is over 80 degree, and if I do, I water first, apply very diluted soluble, then water again.

If your soil is rock-hard-clay and very alkaline like mine, then gypsum (22% calcium, 17% sulfur, and 8% salt) is recommended to break-up heavy clay and to de-salt ... best used as soluble in cool temp. If your soil is loamy, sodic (salty), and less alkaline .. skip the gypsum.

Good luck with your roses ... the second picture is easy to fix. The first picture, if only a few brown spots, lots of watering will do. But if it's over 10 brown-spots like what I did, then I had to replace the soil.

This post was edited by Strawberryhill on Wed, Jun 11, 14 at 11:33

RE: What's causing these two problems?

Hi GreenDreamHome: While looking at nutrient-deficiency pics. by Iowa University Extension, I ran across their analysis of boron-deficiency: "Leaves have small dead spots and are brittle. Shoots may not emerge. Deficiency is favored by drought, sandy soils low in organic matter, and high soil pH. " ... see link below for study done by John Sawyer at Iowa State University.

Also the link by British Columbia - Ministry of Agriculture stated, "Boron deficiency: Upper leaves turn bronze to yellow without wilting, and leaves are cupped or curled. "

The link below stated that drought tied up boron in the soil ... thus lots of watering with acidic pH like rain (at 5.6) would release the boron from alkaline soil. Chicken manure is high in boron, zinc, and copper.

With my high pH tap water of 8, I have to put soluble gypsum (with 17% sulfur), or soluble sulfate of potash (with 21% sulfur) to bring the pH down. Both calcium in gypsum and potassium (sulfate of potash) help plants to cope with drought.

Here is a link that might be useful: Nutrients deficiency in plants by John Sawyer

This post was edited by Strawberryhill on Fri, Jun 13, 14 at 13:02

RE: What's causing these two problems?

Below link is an excellent picture of nutrient deficiencies that show the difference between drought vs. fertilizer overdose:

Here is a link that might be useful: picture of nutrient deficiency in corn

RE: What's causing these two problems?

Thanks for the information. I have never fertilized these roses, so that can't be the problem. It sounds like they need more water, and I should check for boron deficiency. We have some old non-flowering rose bushes slated to be removed that have cupped leaves.

RE: What's causing these two problems?

Hi GreenDreamhome: Thank you for the info. You are right that drought can do that. I remember in 2004 we had a drought in Chicagoland, with temp. over 100 degree. My perennials had curled up brown-margins .. so ugly that I had to chop them down.

The link also confirm potassium deficiency in my Gallica band, which I foolishly experimented with bone meal mixed in potting soil. Info. from the link below "Potassium (K) deficiency create small dots on the margins of upper leaflets. When severely deficient, the size and number of dots increase, the leaves become yellow and dry, and the lower leaves drop." The link has an excellent pic. of potassium deficiency with yellow dots at upper margin of leaves.

Bone meal, high in phosphorus and calcium, induced potassium deficiency. One site wrote on how excess calcium can drive down potassium. See below for my Gallica band, destroyed by bone meal in the potting soil. It's both a phosphorus burn, and severe potassium deficiency .. will post a pic. of its improving with sulfate of potash later.

Here is a link that might be useful: Iowa State University on nutrient deficiencies

This post was edited by Strawberryhill on Mon, Jun 16, 14 at 9:11

RE: What's causing these two problems?

helpful posts,thanks for sharing,

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