They are in the same location in the garden, get plenty of sun and water and the plants look as healthy as can be. Why won't they bloom for me?
If they look healthy but will not bloom, then your soil may have too much nitrogen and not enough phosphorus. Lots of nitrogen will produce healthy foliage growth but little to no blooms. Phosphorus is responsible for blooming, so add a phosphorus rich fertilizer to the plant or add some bone meal in around the soil to help promote flowering.
I've planted several guara plants in beds next to the entrance walkway to my house. They seem happy for the most part, but one of them has flowers that are tilting onto the driveway. I've tried talking to the plant, setting it straight and compacting the soil around it, and pondered trimming its flower stalks. Any advice?
This plant would do well with a ring support placed around it.
You can purchase them in most garden centers.
You certainly can trim away the flowers that are falling into the walkway without harming the plant.
https://www.gardeningknowhow.com/ornamental/flowers/gaura/growing-gaura-plants.htm
How do you propagate gaura?
It is oftentimes propagated by rhizome cuttings or seed. Here is more information:
https://www.gardeningknowhow.com/ornamental/flowers/gaura/growing-gaura-plants.htm
Last year it gave me pink flowers. Then in the winter, I cut off the dead stems. Then this year, the plant grew green leaves with a thick trunk. The leaves do not look like the same plant from last year. How did this happen, and has it evolved?
You can try adding a boost of Phosphorous to encourage blooming.
Bone Meal is a good way to do this.
Since the Pink Fountain Gaura is a hybrid, it is feasible that it could revert to a variety that it is cross pollinated with.
It does happen in some plants.
Here is a link to refresh you on the care requirements.
https://www.gardeningknowhow.com/ornamental/flowers/gaura/growing-gaura-plants.htm
Here in San Diego, un-hybridized guara has spread uncontrollably over about 3,000 sq ft in my yard. Do you have any ideas about how I can get rid of it? I hate to use Roundup, but is that my only option? The plant has actually grown through 12" of mulch! I don't have a picture, but it's become almost a ground cover w/pink flowers - not a very pretty plant. Thanks, Barb
I would urge you contact your local Country Extension Office.
They will have some suggestions on how to control invasive plants in your exact region.
It is also good to report invasive plants to your local office.
I moved to Middlebury, Vermont. Is the Gaura plant considered an annual in this climate? I want to know if it can be grown here as a perennial.
The Gaura plant is winter hardy in zones 6 and higher and marginally hardy in zone 5. Middlebury is zone 4b, so yes, Gaura would most likely only grow as an annual in your climate. Here is more about them:
https://www.gardeningknowhow.com/ornamental/flowers/gaura/growing-gaura-plants.htm
When gauras become so tall can they be cut back, become fuller. Do they produce seeds then drop onto soil.
Yes, Gaura will self seed.
This article will refresh you on the care requirements.
https://www.gardeningknowhow.com/ornamental/flowers/gaura/growing-gaura-plants.htm