Question
I live in HOuston Texas. About 4 or 5 weeks ago I bought a couple of very healthy looking 8 inch potted verbena plants from a nursery and planted them in a full sun area that I believe has good drainage.  They looked great and bloomed wonderfully until just a few days ago when they started looking a bit thin in the center of the plant and then stopped blooming.  We did have a week of heavy afternoon showers on a daily basis, but nothing too abnormal for this area.  We now are having 95 degree heat and high humidity.
 My wife has watered them every morning (except during the rainy period) and has fertilized with Miracle Grow once a week.  What are we doing wrong?  What would cause the plants to suddenly stop blooming?I thought verbenas bloomed until the end of the summer or later.  Also, will they return next year if we leave them in the ground?  If so, should we prune them and when?  Thanks.

Answer
Hi Tom.

I'm not exactly sure what's up with your verbena, but here are my ideas:

1. The soil is not as well-drained as you think it is. Have you done the test where you fill up a hole with water and time how long it takes to empty? You may want to give that a go to double check.

2. The plants are too wet. Watering them every day is certainly too often. Verbena likes a deep and infrequent watering. If all the plants are in the same area, I suggest laying a soaker hose around them (under mulch if your like--leaf mold would be good) and giving them water through that for 2-3 hours once a week. If they do look wilted a couple of days after you water like this, you may need to water them this way twice a week. When I cared for these plants in a garden center, I waited for the leaves to droop before I watered.

3. They have too much nitrogen. Nitrogen encourages plants to put out lots of green growth and too much nitrogen can stop them blooming. Stop feeding them Miracle Grow for a month and see if that works.

You're correct--verbena should bloom throughout the summer and even into fall. In your area, verbena will return next spring (as long as the plants live through the summer). What you will want to do is to cut the plants to the ground around Thanksgiving or whenever they stop blooming in the fall. You may want to cut them now too, though. Since they seem to be dying out in the centers, I would guess that they're looking a little scraggly. If so, you could cut them fairly severely (reduce them by half) to reinvigorate the plants, encourage stronger roots and a bushier habit. If you do this, you'll want to water them deeply that same day (cut them in the morning and put the water on right after that).

I hope this helps you out. I hope they perk up for you soon. Good luck!