Ask a Question forum→Are the brown spots on my hoya krohniana something to worry about?

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Sunny Southern California (Zone 10b)
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Sproquita
Jun 17, 2019 10:58 AM CST
The leaves of my Hoya Krohniana have "calloused" beige spots. You can see it most clearly on the bottom leaf. Do you know what this is?

Thumb of 2019-06-17/Sproquita/57dfdb

Regards,

Lisa

Name: Daisy I
Reno, Nv (Zone 6b)
Not all who wander are lost
Garden Sages Plant Identifier
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DaisyI
Jun 17, 2019 11:26 AM CST
It looks like you are about to have a major outbreak of something. I would find some Insecticidal Soap and spray each leaf, top and bottom, to dripping and wipe off whatever they are with a cotton pad. Get the nooks and crannies.

After you are done, come back to this thread with photos and updates. Good Luck!
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and proclaiming...."WOW What a Ride!!" -Mark Frost

President: Orchid Society of Northern Nevada
Webmaster: osnnv.org
Name: Will Creed
NYC
Prof. plant consultant & educator
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WillC
Jun 17, 2019 11:58 AM CST
Do the spots wipe or rub off or are they a part of the leaf structure?
Will Creed
Horticultural Help, NYC
www.HorticulturalHelp.com
Contact me directly at [email protected]
I now have a book available on indoor plant care
Sunny Southern California (Zone 10b)
Image
Sproquita
Jun 17, 2019 3:16 PM CST
[quote="WillC"]Do the spots wipe or rub off or are they a part of the leaf structure?[

The spots do not rub off. They are beige pits or callouses.
Name: Will Creed
NYC
Prof. plant consultant & educator
Image
WillC
Jun 17, 2019 3:26 PM CST
Then it is not a pest problem. I could be physical damage. Or it might be caused by inconsistent watering. When and how did you repot it? What material is it potted in? Does the pot have a drain hole?
Will Creed
Horticultural Help, NYC
www.HorticulturalHelp.com
Contact me directly at [email protected]
I now have a book available on indoor plant care
Name: kathy
Michigan (Zone 4b)
Zone 4b, near St. Clair MI
Cottage Gardener Lilies Organic Gardener Heirlooms Zinnias Dahlias
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katesflowers
Jun 17, 2019 4:13 PM CST
Hi Sproq
I'm going to agree with Will. I have that same Hoya. In the course of day-to-day living the leaves may get bumped. That's what I've always thought that mark was on my leaf. The injured leaf never died, just stayed the same. The plant is years and years old. It was gifted to me and it was an old timer then. It blooms like crazy, too. So that's why I was never too concerned about the "dry dead spots".
BTW, I water it every Monday and it is in indirect bright sun, in a well draining pot.
"Things won are done, joy's soul lies in the doing." Shakespeare
Sunny Southern California (Zone 10b)
Image
Sproquita
Jun 17, 2019 5:31 PM CST
WillC said:Then it is not a pest problem. I could be physical damage. Or it might be caused by inconsistent watering. When and how did you repot it? What material is it potted in? Does the pot have a drain hole?


Someone on youtube recommended this mix: 1 cup cactus mix, 1/2 cup orchid mix, and 1/4 cup perlite. The soil had fallen out of its cup when I received my Hoya in the mail. So, I put it back in the cup it came in (which has drainage holes) but used my soil mix. I don't have the plant on a regular watering schedule. When I tested a few days ago, it was bone dry. Also, I added Miracle-Gro Indoor Plant Food to the water. Maybe I stressed the poor thing by not keeping it moist and then adding fertilizer? I also just drenched it with insecticidal soap and Neem oil.

Name: kathy
Michigan (Zone 4b)
Zone 4b, near St. Clair MI
Cottage Gardener Lilies Organic Gardener Heirlooms Zinnias Dahlias
Garden Art
Image
katesflowers
Jun 18, 2019 5:54 AM CST
Sproq - thank you for the acorn !
Here is a picture of some of my Hoya.
Thumb of 2019-06-18/katesflowers/7ecac6
Thumb of 2019-06-18/katesflowers/939a3b

"Things won are done, joy's soul lies in the doing." Shakespeare
Name: Will Creed
NYC
Prof. plant consultant & educator
Image
WillC
Jun 18, 2019 8:17 AM CST
That potting mix may be a bit too porous especially with the addition of the bark Orchid mix. It is a hard mix to keep appropriately damp. I suspect that the leaf spots are a result of the roots getting too dry or receiving water unevenly. There may have also been some damage done to the roots during shipping and/or repotting. In any case, the spots are permanent. The key is to prevent spotting on new leaves.

Trying to replace the potting mix now might just cause further stress to the roots, so you will have to adapt your watering to the existing mix. I suggest that you treat it like an Orchid. That would mean taking it to the sink weekly and letting lots of clear water run through the potting mix until it is pretty well saturated.

Keep it close to a moderately sunny window. Fertilize it at half-strength once every 4-6 weeks. No need to treat it for pests.
Will Creed
Horticultural Help, NYC
www.HorticulturalHelp.com
Contact me directly at [email protected]
I now have a book available on indoor plant care
Sunny Southern California (Zone 10b)
Image
Sproquita
Jun 18, 2019 8:56 AM CST
I will do as you suggest. Thank you for your help. What do you suggest as the best potting mix for hoyas? I am about to go to a farmers market this morning and buy a Hoya Bella!

Name: Will Creed
NYC
Prof. plant consultant & educator
Image
WillC
Jun 18, 2019 2:24 PM CST
Leave it in the pot and potting mix that it comes with. That is what the plant has adapted to. You can't improve on it. If you can, then don't buy it.
Will Creed
Horticultural Help, NYC
www.HorticulturalHelp.com
Contact me directly at [email protected]
I now have a book available on indoor plant care

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