These plants are 7 years old. Something is causing the leaves to fall off.
Plants can lose leaves for a number of reasons such as disease, pests and environmental issues. If you are unsure which it is, then try treating the plant with a fungicide, a pesticide and double check that it is getting all the water and nutrients it needs. I personally like to treat plants with neem oil as it is organic and is both a fungicide and a pesticide.
This article may also help too:
https://www.gardeningknowhow.com/garden-how-to/info/plant-dropping-leaves.htm
We have high sodium water. Will abelia or althea grow in zone 7?
Both of these plants are salt tolerant and should do well where you are.
I live in Ohio and planted 2 of these shrubs last fall. We watered them frequently taking care to not overwater them. Over the winter both shrubs have dropped all their leaves and I don't see any sign of any new ones emerging, as spring is upon us. I'm unfamiliar with this type of shrub and am curious if our harsh winter killed them, or do they sprout leaves later spring/early summer?
It is normal for abelias to lose half or all their leaves during winter in colder regions such as yours, but new leaves should reappear in the spring once things truly start warming up. The best thing I can prescribe at this time is patience.
For more information on growing abelia, please visit the following link:
https://www.gardeningknowhow.com/ornamental/shrubs/abelia/planting-abelia-bushes.htm
11 year old abelias in full sun, too large, do not bloom till late summer, and then not heavily. These were supposedly Little Richard Abelia put in by a landscaper. Should I cut them way back next winter? Janie
Pruning is best done in the winter when the plants are dormant.
Since yours are well established it may be a good idea to go ahead and remove some of the old growth. This should help get the shrubs in better shape and should encourage flowering.
Do not remove more then 1/3 of the plant at any prune.
You can also fertilizer with an Azalea fertilizer, twice a year-late February and early June is a good time to fertilize.
https://www.gardeningknowhow.com/ornamental/shrubs/abelia/planting-abelia-bushes.htm
I can find no info about YELLOW FLOWERING Abelia. We have them intermixed with pink flowered plants at my church. I gathered seeds of both colors to plant in my yard [zone 5). Can I plant the seeds now? Blessings.
Abelia can be propagated by cuttings.
Seeds are sterile and will not produce.
There are many varieties of Abelia that are yellow in color including the varieties Lemon, Super Gold and Golden Anniversary to name a few.
Here are some links with more information.
https://www.gardeningknowhow.com/ornamental/shrubs/abelia/planting-abelia-bushes.htm
https://content.ces.ncsu.edu/plant-propagation-by-stem-cuttings-instructions-for-the-home-gardener
What type of fertilizer does an Abelia need and when do I apply it?
Amending your soil with organic matter will actually be better for your Abelia than straight fertilizer. There's a link in this article that may help you learn what to amend your soil with:
https://www.gardeningknowhow.com/ornamental/shrubs/abelia/planting-abelia-bushes.htm
I have three Abelias in my backyard. Two of them are doing quite famously, but one seems to be languishing a bit. - All three are on the same sprinkler system and receive the same amount of water. - One of the two flourishing plants gets the same amount of sunlight (all day until late afternoon). I've attached photos, one shows the plant I'm concerned with and the other shows its companion get gets the same amount of sun.
For some reason that escapes me, the photo of the Abelia which is failing to flourish did not post.