Hibiscus Mystery

Kwajalein, Marshall Islands(Zone 11)

Hello friends! A while back Randy asked me to contribute to his blog with an article on Hibiscus. I was flattered, and agreed...then life entered the picture and I didn't get the article done. Now I have a mystery that, until I can get it solved, I don't feel qualified to write about anything!

This beautiful hib, is now a quarter of its size in this picture. For some reason, a few of my hibs are dying from the top down. The whole plant will look happy and healthy, but the top couple of inches will be dead and brown. I cut off the affected area, and a couple of weeks later, the same thing happens. I have read everything I could find, checked for bugs, checked the soil, I can't find any explanation! This really has me crazy, because I do love my hibs...and this one is so pretty...was so pretty. At first the problem was only with this one, but now it seems to be affecting many of my other hibs, and I am frantic!

Any ideas? Please??

Yokwe,
Shari

Thumbnail by Islandshari
(Zone 9a)

Yikes, Since this is happening to several plants I think you can assume the roots are OK. When a plant, which is receiving adequate water and food, dies from the top down it sounds like they are succumbing to some type of ailment, possibly fungal, that is entering (and blocking) the plant's vascular system as a pathogen and causing wilt and eventual death. These maladies are often vectored by an insect but as soon as the bugs leave their calling cards they take off to get the next available victim so they are hard to see. I wouldn't know if you have an extension service where you live but I would definitely send a specimen, include both living and dead wood, somewhere for evaluation.

Many of the plumeria on Kauai are falling to something like this right now. Most of them looked pretty puny.

I sincerely hope I am wrong and good luck.

Kwajalein, Marshall Islands(Zone 11)

Oh, I hope you are wrong...but it sounds too likely! No extension service out here...and no experts either! Any idea on treatment?

Yokwe,
Shari

Keaau, HI

Hi Shari, Stem Boring Beetles do that to plants here. Have a look at stems that are dying; if there are Stem Borers, they will be right in the stem where the plant changes from healthy looking to sick. There would be a little hole with saw-dust looking stuff coming out.
If you do find Stem Borers you can cut off the branch that contains them and burn it. Another way is to cut into the branch, find the bugs and smash them.

Stem Borers will jump from branch to branch, bush to bush and become more of a problem if they are not controlled.
Several years ago they attacked my Coffee patch. Once I figured out what was wrong, I had to go out and regularly look for the little holes and kill them, till I couldn't find them anymore.

Good luck with your plants!

Aloha, Dave

Kwajalein, Marshall Islands(Zone 11)

Thanks to both of you for your help and suggestions. I will continue searching, both for a fungus, and for the beetles. On my way out side now...

Thanks again!

Yokwe,
Shari

Kwajalein, Marshall Islands(Zone 11)

Dave, your response got me to thinking...

I have always had problems with that area of the garden. Every plant I have put there with a stem - Ixora, Hibs, etc, has ended up with problems. The plants that thrive there are all "leaves/flowers only". So, what I'm wondering is this, could there be a species of stem borers that live in the palm tree in a sort of symbiotic way - it seems perfectly healthy but with smal holes - but that step out and attack any other stems in close proximity? I've never paid any attention to the holes, because all of our palm trees have holes...I just thought they were from the trimmers, but maybe that's not all. Hmmmm....am I making any sense?

In any case, since I have finally put this info together in my alleged mind, I will now move anything with a woody stem away from this area and see if they improve.

Yokwe,
Shari

Keaau, HI

Definitely should check your infected plants for the bug.

They very well could be harboring in the palms. Stem Borers are said to live in the wild Bamboo Orchids here, and jump from there onto folks garden plants.

Kwajalein, Marshall Islands(Zone 11)

Will do. Thanks again for the help!

Yokwe,
Shari

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