All the new leaves of our common red hibiscus are yellow. The same thing happened last spring too, and the leaves later became green, as were all later new leaves. We live in southern South Australia, the hibiscus is on the north side of the house but most of the lower parts (which are where the new leaves are) are shaded by neighbour's trees until mid afternoon. It is about 5 metres high and could be thirty or so years old. Can anyone suggest why the yellow leaves, and if we can or should do anything about it?
This article will help you pinpoint the cause.
My hibiscus are planted in the garden I live in new england can I leave them outside?
If your hibiscus is hardy, and not the tropical variety then it can survive in ground. If it is tropical, then it will need some extra care. Here is an article that will give you more information: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/outdoor-hibiscus-care.htm
How can I cut it back and still have it perform like it has for the last 10 years, but it has gotten to be over 6 foot tall, it has a base about a foot in circumfance?
This shrub is quite different than most, as it like to be pruned hard in the spring. You will want to do this right before the new growth starts for the best results. Here is an article for more information: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/tips-for-pruning-hibiscus-plants-when-to-prune-hibiscus.htm
Any tips for encouraging hybiscus healthy growth?
A proper site with enough sunlight, well-drained soil, appropriate watering, and some fertilizer if necessary will help your hibiscus grow. This article will help you:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm
Here are our other hibiscus articles:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/
Should I prune my hibiscus after I have brought it inside for the winter?
It is best to prune these in spring before the new growth comes out. This article will help you: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/tips-for-pruning-hibiscus-plants-when-to-prune-hibiscus.htm
How to treat for leaves turning yellow w/ brown, crispy edges?
These articles will help you:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm
https://www.gardeningknowhow.com/plant-problems/environmental/what-causes-brown-edges-on-leaves-of-plant.htm
Can the plant be cut back?
You will want to wait until spring to do so. This will give you best results. This link will help:https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/wintering-hibiscus-indoors-winter-care-for-hibiscus.htm