Porterweed (Stachytarpheta spp.)

• Common Name: Porterweed
• Recommended Use: Warm season annual, large container plant.
• Exposure: Full to partial sun.
• Size: Approximately 3 to 5 feet tall, 3 feet wide.
• Habit: Upright to rounded form.
• Bloom Time: Summer through fall.
• Maintenance Category: Low.
• Water Use: Average.
• Highlights: As a butterfly magnet, this will be one of the most popular plants in your pollinator garden. Unique fountain habit with colorful flowers that flow out from the center and bloom over time.

Summary

With showy flowers borne on long, narrow floral spikes, porterweed beckons the attention of people passing by and a host of pollinators. Hummingbirds and butterflies particularly appreciate the flowers of porterweed, which are commonly seen in shades of blues, purples, pinks and reds. We couldn’t choose the best, and that is why we are naming all of the porterweeds to be Louisiana Super Plants. The blooms are sustained throughout summer and into fall. Porterweed is a showy, small plant that can sometimes perennialize; however, it should generally be treated as an annual in the Louisiana landscape as it will not outlast a freeze. The defining feature of this plant – the thin floral spikes that extend color above the compact, green foliage – looks great all summer long in landscape beds or container arrangements. Porterweed is an excellent choice for those looking to add sources of color and nectar to their garden. Advancements in breeding efforts have yielded a plethora of pretty flower colors to select from, as well as a range of heights that can accent landscapes of all shapes and sizes. These tough plants can do more than tolerate the heat, humidity and sunlight that we typically enjoy in Louisiana – they can thrive in it. Once established in the landscape, porterweeds can tolerate high rainfall, provided there is at least sufficient drainage, or short-term drought. As far as low-maintenance annuals that bring forth a bevy of colors, porterweed stands out with its unique floral spikes. While the individual flowers may be small, they captivate as a whole when observed in the entirety of the floral spike, particularly as they sway in an afternoon breeze. This is an incredibly unique plant that is well deserving of all the new attention it receives. Plus, some are native to south Florida, so it is native to the U.S. For these reasons and more, porterweed – and we do mean all porterweed – is a Louisiana Super Plant for 2024.

Requirements

• Well-drained soil preferred.
• Full sun to partial shade is ideal.
• Fairly drought tolerant and relatively low fertility requirements.
• Sensitive to frosts and freezes.

Growth Habit

• The floral spikes grow upward and extend above the relatively compact foliage.
• Floral spikes may grow sideways, twist or turn (particularly on lower or drooping branches), creating appealing strips of color in varying directions.
• Different varieties provide a range of sizes to use.