Allan Armitage: Let’s Talk About Starflowers. Why Is Pentas Not More Popular?
It is good to talk about production techniques, performance results and then to see how our friends garden. Diversity of plant material has always been a strength in American garden centers, and we should never run out of plants to get people excited.
However, perhaps people are tired of Petunias or Callas or Geraniums, but we will never run out of options to put in front of them.
One plant that is often overlooked is Pentas, a fabulous summer crop for late spring sales. These are heat-tolerant plants, and growing them below 65°F in the greenhouse results in significant delay. Fertility should be at least 150ppm nitrogen, but avoid ammonia in the fertilizer. Plants are best grown at a somewhat higher pH than usual, between 6.4 to 6.8.
For best presentation, pinch out the center bud. Side flowers will bloom together, and plants will walk off the shelf. Garden centers can sell them in the spring shoulder season, but they are useless if sold too early. The crop time is eight to 12 weeks from a liner, depending on finish size.
In the landscape, Pentas’ reputation for heat (and humidity) tolerance is well-deserved. They eat up heat and maintain color in the landscape all summer. I am not sure why this is not one of the top five annuals on grower and consumer lists, but it seems to struggle with some respect.
While Pentas may not be a plant for everyone, it is a crop that almost anyone can do well with. Pentas have been around for many years, but as I look ever more critically at plants for warm temperatures, I can see some excellent choices.
Pentas For The Garden
Here are some I have evaluated over the years, and ones I do not hesitate to recommend to friends and family.
Graffiti Series (Benary Seed) is a seed item that is still a strong plant in many markets. It has about seven colors and is short and compact, about 15-inches tall. ‘Graffiti Rose’ has always been one of my favorites, but Red Lace comes a close second.
The Butterfly Series (PanAmerican Seed) is also a vigorous seed-propagated group of plants. They grow about 12- to 20-inches tall in the landscape but have performed well around the country. Cherry Red is my favorite for best performance.
Starcluster Series (Syngenta Flowers) is a relatively new vegetative offering and is outstanding. The stems are strong, and the large flower clusters are dense and showy. My favorite is ‘Starcluster Lavender’ but the Red is also an excellent performer.
Piñata (Dümmen Orange) is a new vegetative series of Pentas. Plants are quite short, from 12- to 14-inches tall, and available in four colors. They were first shown at California Spring Trials and are available in numbers for 2016. No performance trials have been published, but the plants appear to be positioned to do well. You will also see them in the HGTV program under the name Gypsy Heat.
Those are some Pentas that everyone should be able to find, but I would be remiss if I did not list my all-time favorite — Pentas ‘Stars & Stripes.’ It may be more difficult to find, but if you can, this is an in-your-face-make-you-smile plant. Originally introduced by the Athens Select group many years ago, it may still be in production.