I posted this on the hibiscus forum and haven't had a response yet. Do these leaves just look sunburned or does it look like another problem? I did a very hard prune about a month ago due to the previous owner not properly caring for her for a very long time. She was very woody with a large patch of leaves growing towards the small window she was near. Since the prune her leaves are growing in very nicely but they are developing white patches since I moved her to my porch two weeks ago.
I'm actually curious about this myself as a few of the leaves on mine are looking similar. Mines really healthy overall but from time to time a leaf will take this look to it and it's been driving me nuts. I keep it on my porch in full sun all day as well.
I'm concerned I'll never get blooms from mine. Living in an apartment in ny I don't exactly have the greatest tropical plant growing conditions. I am hoping that if it is in fact sunburned leaves it may be getting enough direct sun to stimulate blooms this year
Sounds like more a Physiological disorder either not enough watering OR too much, have you changed anything other than pruned, have you moved the plant to different light / shade etc.
Is the soil correct for Hibiscus, they like a peaty soil, also once you begin to water after winter resting, you need to offer a liquid feed every few weeks while the plant is growing. I would say an indoor plant feed from store would be fine BUT start half dose first time so the plant is not put into shock.
Make sure you DONT cut into woody parts of the stems when you tidy it up, just snip off enough softer parts or you may NOT get a lot of flowers this year, Give plenty light BUT Not sun blazing through glass or you dehydrate the plant AND burn the leaves, put the plant outside in high temps as this circulates air around it and helps prevent infestations of greenfly or other sucking insects as well as the plant enjoying the sun and clear air away from any cooling indoor systems.
Hope this gives you food for thought and things can pick up a bit so you can begin to get enjoyment from your lovely plants.
Good luck. Kind Regards.
WeeNel.
Thanks for your response Weenel. Yes, she has moved twice over the past three months to different light intensities. She was being kept by my neighbor in a dark room, and once I took her in I had her in a SW facing window until it warmed up and I moved her to my porch in front of a SW window. I had to cut into the woody parts of the plant when I pruned her because her branches were completely unmanageable and she just didn't look good. I read that a hard prune shouldn't hurt as long as you only di it as needed with a few years in between. I use a low phosphorus high potassium fertilizer and feed at a quarter suggested amount every time I water rather than once ever two weeks. I water when the soil feels dry at about 2 inches and don't allow her to stand in water. I unfortunately don't have an area to put her outside.
The picture (the leaf on the right and sort of behind/under to the left) sure could be sunburn, especially with the history given.
Moving a plant from dark to light (especially direct sun) can create sunburn. Not much you can do about it now. The new leaves will come out acclimated to the sun, so no need to worry that way.
If you need to do this again (or for other people reading this post) use a shear curtain over the window when you first move the plant, then open the curtain a little more every few days so the plant can get used to the sun.
When they grow in the shade they do not develop quite so thick a skin on their leaves and when this thin skinned leaf suddenly is exposed to the sun it can burn.
I am also concerned about the green leaf to the left of the sunburned leaf. It is sort of wrinkled? Almost warty? If so, this could be a pest that needs some attention.
