monarch butterfly on a blue porterweed

How To Care For And Grow Blue Porterweed

Since the Blue porterweed is a low-growing native of South Florida that produces little blue blooms almost all year, it is a good choice for enticing pollinators. It’s also an excellent groundcover. Blue porterweed is a short, spreading shrub with a delicate appearance. However, some may be surprised that this natural plant of the tropical southeast is being grown for the finest of gardens. For a long time, it was regarded as a weed. The leaves are appealing because they are crinkled and toothed. It is a herbaceous perennial that develops to be woody towards the base of the stem after about a year.

Growing The Blue Porterweed 

Before the stems droop and touch the ground, plants grow to be approximately 4-feet tall by 6-feet broad. Blue porterweed blooms are approximately a quarter-inch in diameter. They blossom towards the ends of the stems. Porterweed is a lovely addition to any sunny environment with its rich, dark green leaves and square, green stalks. Because Porterweed blooms profusely and attracts a variety of butterflies. They are all drawn to its delicious nectar. Garden cultivars with purple, blue, or coral flowers are therefore more popular.

Here are some brief facts about the popular aesthetic plant:

  • Latin name: Stachytarpheta jamaicensis
  • Other names: Blue snakeweed, Bastard vervain
  • Native to:  American Tropics
  • Invasiveness: No
  • Tenderness: Herbaceous perennial 
  • Sun: Full Sun to partial shade
  • Water: Below average
  • Soil: Well-draining
  • Hardiness zone: Zones 9b through 11
  • When to plant: late spring-summer
  • Spacing: 2-1/2 to 3 feet
  • Plant height: 4-5 feet
  • Bloom period: Spring to summer
  • Time to maturity: 
  • Container friendly: Yes
  • Fertilizer: 10-10-10
  • Toxicity: No
  • Deer resistant: Yes
  • Pest resistant: Yes

The plant is unaffected by direct sunlight or drought. They require wet soil when first planted, but once established, they can withstand drought pretty well. They may also withstand saline environments. Plant them 2.5 to 3 feet apart if you’re using them as a groundcover (1 m.). They will sprawl out and form a lovely continuous bed of blooming shrubs as they develop. In late spring, prune the bushes vigorously to foster fresh summer growth. You may softly trim them throughout the year to keep an even height and pleasing form.


Water these plants on a regular basis, but don’t overwater them. Hydrate the plants well. Water one to two inches deep, and then wait until the top layer of soil has dried before watering them again. A fungus can be spread by overwatering Blue porterweed.


The plant thrives in direct sunshine. It can also be used in gloomy or filtered sunlight. Porterweed requires regular watering since it enjoys wetness. It might start to die at low temperatures.


This versatile shrub will thrive in any well-draining soil, even lime rock. This plant prefers wet soil, therefore water it on a daily basis. It can survive for a few days without water. When you notice wilting leaves, it is merely due to a lack of water; water it quickly and it will appear rejuvenated.


Fertilize with an excellent granular fertilizer in the spring, summer, and fall. Apply bone meal and/or liquid fertilizer because it will produce more blossoms. When planting, fill the hole with topsoil or organic peat humus. You may also include composted cow dung.


Blue porterweed is not invasive. Because both have unique purplish-blue blooms, the non-native Stachytarpheta cayennensis is sometimes confused with the natural species. Because it has escaped cultivation and is affecting its natural habitat, S. cayennensis is classified as a Category II invasive species. It is not to be planted. The native species, S. jamaicensis, has a more drooping habit than the S. cayennensis.

Growing The Blue Porterweed In Containers

Blue Porterweed will grow and blossom happily in a container or in the ground since they are a lovely addition to any outdoor area, garden, or patio. Containerized plants can be moved indoors for the winter months in milder climates. Blue porterweed can be planted in a pot by itself or as a focus in a larger container arrangement.

Care & Tips

Blue porterweed is drought resilient, salt-tolerant, and thrives on poor soil. Its low-growing nature makes it an excellent groundcover in dry, sunny conditions. It also looks great in a pot or in a combined wildflower garden. Cut Blue porterweed to keep its size and form. Cutting the old flower stalks will keep the shrub looking clean. It can stimulate a few more blossoms because it will not direct energy towards seed formation. Simply cut the flower spike at the base.

Common Problems

The most common Blue porterweed problem is powdery mildew. Ensure that the plants have proper air circulation and are not overcrowded to avoid this. Hydrate throughout the day rather than at night since Blue porterweed favors warm, damp settings. So, water slowly and carefully, directing the water into the ground at the plant’s root to avoid water on the leaves and stems.

Propagating The Blue Porterweed 

While Blue porterweed is a short-lived perennial, it will self-seed and may be reproduced by stem cuttings. Blue porterweed attracts a high number of butterflies despite the fact that the blooms are tiny and only bloom for one day. This plant can be propagated easily by immersing any stem node in freshwater or perlite for 2 weeks.

Wildlife Attracted By The Blue Porterweed 

It blooms in the summer amid coastal dunes, shell mounds, and rough places. However, it blooms all year in South Florida. It’s a nectar source for several butterfly species, including the Tropical buckeye (Junonia evarete), Clouded skipper (Lerema accius), Red admiral (Vanessa atalanta), Gulf fritillary (Agraulis vanillae), Monarch (Danaus plexippus), and Julia (Dryas iulia).

Uses For The Blue Porterweed 

Blue porterweed has been used to cure anything from fungal infections to high blood pressure, boils, constipation, burns, diarrhea, headache, worms, earache, allergies, and “nervous symptoms.”

Blue porterweed isn’t simply for bees and butterflies. Since the flowers have a mushroom-like taste and may be eaten uncooked. To season soups or stews, use flower spikes like you would a bay leaf. Dry the leaves and steep them in a frothy tea or brew them into beer. The common name, porterweed, is derived from the porter type of beer that the tea resembles.

Porterweeds are probably the most popular nectar plant among butterfly gardeners and, without a doubt, the butterflies themselves. Porterweed is used in mass planting along with foundations or as a trimmed or natural uncoiled hedge to add color to the landscape.

Mayukh Saha
Freelance Writer
Mayukh is a Content Marketer and Social Media Manager with over 5 years of experience in the industry. Mayukh believes in the power of content; how it can positively impact lives, scale businesses and touch people. In his spare time Mayukh likes to read about latest tech trends and loves to travel in the nature. You can reach him at [email protected].