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Roses- Brown leaves / dying

Posted by slowstart 23150 (My Page) on
Sat, Jun 29, 13 at 14:34

Have 4 roses that I bought spring of '12 (fragrant cloud, Elle, double delight, something else) kept them in 3 gal pots and planted them this spring. They did well all through last year and had nice roots when planted out this spring. Planted them in an area where I had just cut down a large pine. Root is still in ground. Dug nice hole with a lot of potting soil for roses. They get 5 hours of nice sun. Drenched with systemic treatment for black spot and mulched with pine needles. 1st month was fine, then leaves started loosing green. Treated with 2nd systemic 8 weeks later and no more new growth, leaves dropped off and what leaves didn't are brown and spotted and dry looking. Live in Z7 Va. This has been the best spring in years for rain and mild temps. Every thing else in garden in best ever. Have grown roses before with success.
Is this a problem with location (pine tree) or systemic treatment -Bayer?


Follow-Up Postings:

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RE: Roses- Brown leaves / dying

Could you post sharp images of some of the sickly leaves lying flat? Or at least give detailed descriptions of the leaves and spots.

Dry, curling lower leaves could be spider mites, but that seems unlikely in mild, rainy weather.

None of the regulars here recommend the Bayer soil drench. As hooovb said recently, the fertilizer is low quality, the insecticide is unnecessary and potentially harmful (can encourage spider mites), and the fungicide is inadequate. The same fungicide ingredient packaged as a spray concentrate works very well (Bayer Disease Control for Roses, Flowers and Shrubs).

A measuring error with the drench, or any fertilizer, can cause burn and leaf drop. You may have blackspot disease that the drench didn't control effectively. Possibly the imidocloprid insecticide in the drench caused a spider mite outbreak.


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RE: Roses- Brown leaves / dying

I suggest you do a Google search for the alleopathic properties of pine trees.

Not all pine trees are have alleopathic properties, but some do. This is how the pines compete for space in the forest. The emit a toxin either through their roots or even through the decomposing pine needles that inhibits nitrogen uptake in other plants or emit an acid that can inhibit the growth of other plants.

It's interesting reading.

Smiles,
Lyn


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RE: Roses- Brown leaves / dying

here is a pic. I wonder about the pine. I have used the tags for mulch for other plants over the years but it could be mix of soil and tags. The leaves are browning from edges as mulch as loosing their green. Thanks


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RE: Roses- Brown leaves / dying

Looks like iron chlorosis, either too high ph (alkaline) or something else preventing iron uptake.

I have high ph in some areas of my gardens and have had roses look like yours when newly planted. My solution has been several overhead waterings of 3 Tbs. Miracid fertilizer and 2 Tbs. Bonide Liquid Iron in 2 Gal. water . I soak the leaves as well as the ground once per week . The mixture does make the old growth look crummy but the new growth looks wonderful. Once they get established, I haven't had to use it again.


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RE: Roses- Brown leaves / dying

The pale leaf blades with green veins indicate iron deficiency, as t-bred says. Check the pH and use sulfur to adjust it to 6.0-6.5. This takes a while. Excessive phosphate fertilizer and water-logging can contribute to iron deficiency.

The brown leaf edges are probably caused by excess nitrogen fertilizer. Contributing factors can include salty soil, heat, and erratic water supply.

Thanks for posting a good picture.


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RE: Roses- Brown leaves / dying

Pine needles will produce a very acid soil, which might be 5.5 or so. You need the ph at 6.3-6.5. Limestone is the only thing that will get it where you need. The only way to find out is a soil test!


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RE: Roses- Brown leaves / dying

Pine needles will NOT produce an acidic soil. If they did, all I would have to do to grow blueberries is to plant them near the pines. It doesn't work.

I do wonder about the potting soil they were planted in, though. Usually potting soil isn't a good amendment for garden soil, and there may be serious water issues with the interface between the two soils, or nutrient issues if the potting soil is sterile and without fertilizer.


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RE: Roses- Brown leaves / dying

hello mad:

Second that remark about pine needles - it's one of those garden myths that won't go way. If you are lucky enough to have access to pine needles, they make a great mulch.

Please ask permission if they are not on your own property and don't take pine needles from natural areas.

Here is a link that might be useful: Pine Needles Cause Acid Soil - Fact or Fiction


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RE: Roses- Brown leaves / dying

The local nursery told me recently that the best way to acidify soil is to pour a can of Coke on it.


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RE: Roses- Brown leaves / dying

It's true that pine needles do not create acidic soil. However, when I was doing some research about the alleopathic properties of pine trees, I found that not all pine trees or all parts of pine trees have alleopathic properties.

In my research, I found that the pine needles of some pines release an acid while they are decomposing as a method of inhibiting the growth of other plants within the drip line of the trees. Once the needles are fully decomposed, they are harmless other than the fact that dense coverage of the soil with the needles also inhibits the growth of other plants.

As I understand it, this really does not have any impact on the ph of the soil.

Other pines release chemical toxins that inhibit the uptake of nitrogen by other plants.

Competition in the plant world is incredibly interesting and complex.

Since Slowstart did not identify the type of pine tree that s/he removed, I recommended the Google search because how the trees compete for space in the forest varies.

Smiles,
Lyn


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RE: Roses- Brown leaves / dying

I have read in reputable sources that no North American pine species are toxic to other plants. In other parts of the world, there are many pine species that are toxic.

Pine needles are fine for mulching.


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RE: Roses- Brown leaves / dying

While PH can more easily be altered to create a more alkaline base, I find the reverse impossible, at least for anything remotely long-term. I would probably be using a sequestered iron supplement to try to adjust the iron take-up in your rose (something such as Sequestrene)


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RE: Roses- Brown leaves / dying

Thanks, Michael. I may have been posting misinformation. I am pretty sure I didn't check to see where the research was done when I was checking for alleopathic properties in pine trees.

Ooops...

Lyn


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