Dear Mr. Gill,
You have come to my aid once before when I was unsure how to rehabilitate a yard full of drooping elephant ears after a freeze. Thanks to your advice, our gigantic elephant ears are flourishing once again. I am so grateful to you for pointing me in the right direction then, and I am hoping you might be able to help solve another plant problem.
We have several lantana plants in our front yard. Last year they thrived and produced blooms over and over again for several months. This year, they have only produced one sparse round of blooms. It's been more than a month, and they have yet to produce any more. I fertilized all of the plants in early spring with organic blood and bone meal, which they loved last year. Most of the plants are in an area that gets a mix of sun and shade throughout the day, and continue to grow. But they just aren't blooming. Any idea why not? And is there something I can do?
And then there is the issue of my favorite lantana. It’s a transplant from my grandmother's yard. Last year it was perhaps the most prolific of all the bushes. This year, we moved it to a new spot just a few feet away from where it was. Both spots get a lot of sun and are equally sunny. The lantana was a little traumatized at first, but with some fertilizer and lots of water it eventually perked up and began filling out nicely for a while. Several months later it is on a steady path of decline. Its leaves have toughened and many are beginning to brown on the edges (see photo). I'm not sure if this has any significance, but the toughened browned leaves still cling to the bush, unlike most dried out leaves which fall off easily.
I've tried watering it more and less. I am afraid to fertilize it again for fear of overdoing it. All of the surrounding plants (a Confederate jasmine, some pentas and black-eyed-susans) are doing just fine, and they receive the same amount of sun and water. I am stumped! Do you have any idea what might be happening and how I can save my grandma's lantana? I'm quite fond of it, and it pains me to see it fading more each day.
Your grateful fan,
The damage to your grandmother's lantana is being caused by a lantana lace bug infestation. Often, the first sign of lace bug infestation is a plant will suddenly stop blooming – they attack the flower buds first (they may be a factor in the other planting of lantanas not blooming). When they move on to the foliage, their feeding causes light colored spots on the leaves, which continues until the leaves look scorched and tan. The backside of the leaves generally have numerous small brown spots (these are fecal deposits).
Although a damaged plant may look dead or dying, it is still alive - only the foliage is damaged. We generally cut the bushes back to remove the damaged growth. Bag up and dispose of the trimmings as you prune them.
Then, spray the plants twice with permethrin (Bonide Eight and other brands) or Malathion following label directions to kill off any lace bugs. An organic option would be a light horticultural oil, such as Year Round Spray Oil, All Seasons Oil, Organocide or other brands. Light horticultural oils will control the lantana lace bugs without harming the pollinators that visit the flowers (such as bees and butterflies). Spray thoroughly under the leaves.
As the new growth comes out it should be healthy. If you see any signs of lace bug damage on the new growth, spray again. Treat anytime you see the symptoms showing up in the foliage.
Consumer Horticulture Specialist