What color are your pentas? I am big on colorizing my gardens. Do you want something that blooms at the same time or do you want it staggered? How big is the area? Lots of the flower companies have have garden plans on their websites you can follow. Whatever you choose make sure it has all the soil and sun requirements as the penta.Since pentas grow to about 18", choose something that grows 24" or more.
Hope this helps.
Thank you, my pentas are dark pinks, I saw a yellow flower with long leaves similar to daylilly but I did not know what it was or if it would do well. I have about 3 feet available behind the pentas. I also considered white crape jasmine, but then thought something spikey would look better? ??