Ask a Question forum: Cycad revoluta chlorosis..?

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Argeles sur Mer . South of Fra
Jan 28, 2017 9:11 AM CST
Was wondering if someone might know of this problem occuring to some of my Cycad revolutas , & only them...!
The yellowing , then turning to brown, occuring on the new leaves gradually as they flush out ; and they do that every year...!
I was told it could be an exces of limestone blocking the iron assimilation....?..!
Any other clues & eventual remedy....?..
Thanks for your help..!
Thumb of 2017-01-28/Dominiquecordonnier/c0df0e

Name: Lee-Roy
Bilzen, Belgium (Zone 8a)
Irises Lilies Hostas Ferns Composter Region: Belgium
Jan 28, 2017 9:29 AM CST
If it only affects the new leaves - and ruling out disease - it means it's a deficiency of an immobile nutrient: calcium, sulfur, iron, copper and boron. Try feeding it with these (root or foliar).

Could also be too sunny
Name: Elaine
Sarasota, Fl
The one constant in life is change
Cat Lover Master Gardener: Florida Tropicals Multi-Region Gardener Vegetable Grower Region: Florida
Herbs Orchids Birds Garden Ideas: Level 2 Garden Sages Celebrating Gardening: 2015
Jan 28, 2017 10:21 AM CST
These cycads grow in full sun here in Florida so that's not likely the problem. But the inability to take up nutrients is the reason, I'm sure.

Is that a border of limestone rocks between the two cycads in your picture? The plant on the right is much more severely affected than the one on the left. Is it higher up, by any chance? If it is limestone there, it's constantly leaching calcium into the soil making the soil around the plants much too high pH for them to be able to absorb nutrients through the roots. The uphill plant would get less of the leaching, the one lower down gets more. A quick fix is to foliar feed (spray the green leaves) with the nutrients Lee-Roy suggests, and soon! Putting the nutrients into the ground is not going to help at this point because the plants can't make use of them.

The long-term fix unfortunately is to remove the limestone, then amend the soil heavily with organic material, or move the plants. If you love the look of white stones, as I see lots of it in your profile picture, perhaps replace those pieces of limestone with some other rocks and paint them (with a non-leaching paint) white to match the rest of your borders? If you have limestone rocks throughout your garden, I fear you'll be seeing more of this type of problem with other plants.

"Success is stumbling from failure to failure with no loss of enthusiasm." –Winston Churchill
Argeles sur Mer . South of Fra
Jan 28, 2017 12:21 PM CST
Thanks both of you for your kind reply. Thank You!
Will certainly apply foliar feed in spring time at first , then on the soil later .
I have already removed the white gravel & sand that used to be around the rocks & added good soil around the plants.
Otherwise the cycad revoluta are the only ones that have these symptoms , even other species of cycads seems not to be bothered by the limestone , & they've be there for 20 years...!
Thanks again..!
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
Jan 28, 2017 3:44 PM CST
It looks like "frizzle top" which is a manganese deficiency (which is often pH related). Here are some pictures to compare:

Edited to add more images:
[Last edited by sooby - Jan 28, 2017 3:47 PM (+)]
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Argeles sur Mer . South of Fra
Feb 6, 2017 6:52 AM CST
Thanks Sooby
For your help & helpfull links.. Thank You!
All the best

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