May 25, 2019
May 26, 2019
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The shrubs are in their third season. This year two of 4 are not blooming or ha e very
, very little bloom or leaves. The other two are fine the growing conditions are the same.
Full sun in a burm.
Some varieties may be a little less tolerant of full sun, but this will not usually hurt the blooming process. It can be attributed to nutrient deficiencies, or moisture issues if water collects in the area. This article will help you start determining what could be the problem: https://www.gardeningknowhow.com/ornamental/shrubs/rose-of-sharon/rose-of-sharon-not-blooming.htm
The lichen, its self, is not a concern. This can, however, indicate that there is another fungal infection present and doing damage to the tree. I would recommend putting wettable sulfur and dolomitic lime around the soil and even a little further from the shrub. This will kill off anything in the soil. Doing this over the winter will give you the advantage as well. The new growth in the spring will be back to normal.
Rose of Sharon is hardy to zone 5 and you are in zone 5b, so you are cutting it close. You may have a couple varieties with a slightly different cold tolerance. Plus, Rose of Sharon shrubs are susceptible to winter injury. To tell if they are alive, pull back a branch and see if it is supple or brittle. If it snaps off the branch is dead. Also you can scratch off about 1/2 inch length of bark to reveal the layer below it. If it is brown, the branch is dead. If it is green, it is still alive. If it seems to be alive perhaps they don't get as much sun as the others and are lagging behind. You can try cutting the shrubs close to the ground to see if they will come back from the roots. If you don't see any new growth within a month, then replace them.
Here is more about their care:
I prune this plant yearly, I have others the same age that have no problems, this yeat it didn’t fill out like it normally does. It does have healthy leaves on it but they are small. It also has buds for flowers; any ideas about what I can do to help this plant?
Examine the shrub for signs of pests or disease.
These articles will help you with accessing the plant and how to treat accordingly.
All the leaves are healthy and there is no sign of damage. Why is it doing that and can it be fixed? The plant is in our front garden which faces due west
The most likely reason is that it is top heavy and the stem cannot support all the weight, so it is bending over with the overburdened load.
Thin and reduce the foliar crown by selective pruning, and consider staking the plant for additional support
If I cut these down to maybe a short stump, would the root system grow new shoots and grow back into a bush? How short would I cut the stump?
Yes, this can help to rejuvenate the shrub, and get it growing like it should again. It will not hurt to aggressively prune these back to the ground if you need.Leaving some stump can help the growth process and help it to be more manageable. This article will help: https://www.gardeningknowhow.com/ornamental/shrubs/rose-of-sharon/pruning-rose-of-sharon.htm