PlantFiles: Blue Porterweed, Purple Porterweed, Blue Rat's Tail, Verbena Azul, Cayenne Snakeweed
Stachytarpheta cayennensis

"Hey, where did that come from?" was my thought when I saw blue Porterweed growing in between and higher than my trimmed snow queen hibiscus. After some thought and consideration, I remembered that the neighbor to the west of me had a stand of the plant in their yard about 100 feet from where mine were a' poppin'.

I was enamored with the purple-blue small flowers and the definite contrast to the variegated white and green leaves of the snow queen. Mine are the woody, tall variety, growing to about 6 feet or more.

As a matter of fact, they have dropped seed and saplings have emerged, which I then transplanted to a less obscure part of my garden. Two of the plants now have center stage near some gloxinia sylvatica (Bolivian Sunset) and variegated agaves in the N.E. part of my garden.

Even though they may be considered invasive, I will keep a tight reign on them and proceed to have a couple of trimmed mounds where I choose. I'm ready for the butterflies and bees to come around also during spring and summer season.

This amazing plant grows very fast in gardens on the east coast of South Africa. It is perpetually in bloom and attracts large numbers of bumble bees, honey bees, butterflies and birds - outdoing even the pentas. It is best grown in clusters to avoid that leggy look and once established is a colourful addition to the garden requiring little maintenance. I have both pink and purple ones but have difficulty in telling the varieties of stachytarpheta apart since s. mutabilis, s. urticifolia and s.cayennensis are so similar.

I have not grown this plant. Porterweed (Stachytarpheta urticifolia) which is a naturalized (introduced) plant in Florida, Hawaii and Puerto Rico. Having had great difficulty identifying a porterweed because some photos on the internet have been misidentified as well as the descriptions of some types of porterweed can be incorrect, I am adding a portion of an article entitled "Plant Profile: The So-Called Porterweeds". This information is written by Roger Hammer appeared on the Florida Native Plant Society webpage (Copyright 2003-2007 --- Revised July 14, 2006) - Reprinted from The Tillandsia (Miami-Dade Chapter), Jul.-Aug. 1994.

"Plants offered in many Florida nurseries and garden shops are either mislabeled or sold under names with no botanical standing. This adds to the taxonomic confusion surrounding the genus. There is but a single species native, or presumably native, to Florida, and that is Jamaica porterweed, Stachytarpheta jamaicensis, sometimes referred to as "blue porterweed." This is a sub shrub growing to a typical height of only one or two feet with a sprawling or decumbent habit. It often forms a dense mound of stems in cultivation. Leaves are dull, light green or gray-green, although some plants may be entirely blushed with purple. The leaf margins are coarsely serrate and the teeth are generally forward-pointing (towards the leaf tip). The leaves are usually glabrous (smooth) above, but may also be pilose (slightly hairy) on the lower surface, and there are no prominent raised areas between the leaf veins. One to several small, blue flowers are borne on green, quill-like spikes. With each passing day, flowers appear slowly up the stem, but each flower lasts only a single day.

Jamaica porterweed is generally considered to be a Florida native, although some botanists believe that this species arrived in Florida along with early Bahamian settlers who brought seeds of medicinal plants with them. This is a species of roadsides and other disturbed sites, seldom being found in undisturbed native plant communities.

All other species of the genus found in Florida are clearly exotic. The most prominent species that is fast becoming established as an escaped exotic in southern and central Florida is Stachytarpheta urticifolia (or S. urticaefoli). This a four- to six-foot woody shrub with violet to purple flowers that, like the flowers of S. jamaicensis, only last a single day. A flowering specimen is quite attractive and is an excellent butterfly attractor. There is a highly-prized white-flowered form (forma albiflora) cultivated on Guadaloupe and Martinique in the Lesser Antilles. Leaves are dark green, somewhat glossy, with acute, marginal teeth that are more numerous and outward-pointing with S. jamaicensis. When comparing these two species, look closely at the leaves and growth habit. The leaves of S. urticifolia have distinct raised areas between the leaf veins, giving the leaf a quilted (bullate) appearance. Growth habits are entirely different; S. jamaicensis is always low and sprawling, while S. urticifolia forms an upright woody shrub with a distinct trunk. S. urticifolia is native to tropical Asia."

I don't think any of you are listening to NativePlantFan9. He is absolutely correct. This plant is INVASIVE. We may think it is nice that it reseeds in our yards, but it reseeds EVERYWHERE.

Please, GO NATIVE with S. jamaicensis.

I stumbled across this plant in a Houston, Texas nursery about 4 years ago and had never seen it before, so I bought it. It was labeled "Porter Weed" with no other identification. I haven't found it offered here in any nursery since, and when I asked about the plant, I was told I would need a better name than Porter Weed to locate it.

This has got to be one of my all-time favorite plants. Though the flowers are small, they are constant, and the deep blue color is eye-catching. My plant is just off the patio where it is seen year round, and it's always beautiful and always covered with butterflies, some of which I've never seen before. They flock to the Porter Weed all day long and cling to the flowers and stalks with wings spread. I've taken some really neat pictures while they pose amid the beautiful blue flowers. Though butterflies and hummingbirds abound, I've never seen any bees around the flowers, which seems a little odd. However, I'm quite happy to avoid the bees. Afraid my one plant might die in a freeze or just get sick, I've tried to start cuttings to no avail. I've only had a couple of plants come up as seedlings, and lost both during transplant. I have just started collecting seed in hopes of starting additional plants. I would recommend this plant to anyone. It's one of my favorites, second only to the Brugmansias that perfume my garden.

This is by far the best performing plant in my garden! I always see it sorrounded by zebra long-tail butterflies during the Fall here in Florida. Seeds are easy to collect when the stems with flowers "die" off.

I love this plant. I have the red, purple and salmon varieties. The red may indeed be a different species as it tends to be a lower mounding shrub unlike the other two that can get leggy. Still and all, they are all very nice plants and a great addition to a butterfly garden. I mulch the bottoms of mine and have never yet as volunteer seedlings. Sometimes I wish I did as it would have me from propagating from cuttings.

Grows well in Gulf Breeze, Florida (panhandle-Pensacola zone 8B). Planted in 2004 in the shade of a medium Dogwood tree (full morning sun, filtered early afternoon sun and full late afternoon shade). In 2005 it took off and has bloomed all year but most prolifically in Spring and Fall. Currently (Oct 05) it is 4.5 feet tall and 4 feet wide. Soil is very sandy with a slight topsoil layer. Butterflies love it.

This exotic species is much more commonly sold in central and southern Florida nurseries than the native S. jamaicensis; however, it is often erronously (and mistakenly) sold as the latter native species. Here are the differences between the two species:

S. urticifolia:
-Large to medium, spreading shrub
-Exotic (not native) to Florida
-More commonly sold than the native S. jamaicensis
-Has thinner, more sharply cut (divided) leaves than the native species, hence the common name 'Nettle-leaf Velvetberry'
-Can get lanky and unattractive after a while, unlike the native species; higher maintenance
-Has smaller, darker violet/purple flowers than the native species
-Has longer, thinner flower stalks than the native species

S. jamaicensis:
-Low-growing, spreading groundcover
-Native to Florida
-Less commonly sold than the exotic S. urticifolia
-Has thicker, narrower, somewhat longer, less divided and less sharp-edged leaves than the exotic species (S. urticifolia) more commonly sold
-Needs less higher maintenance than the exotic S. urticifolia and does not get as lanky and unattractive
-Has larger, lighter violet/light purple flowers than the exotic S. urticifolia
-Has shorter, thicker flower stalks than the exotic S. urticifolia

These are the key differences between the two species.

I originally bought the exotic S. urticifolia and planted a few plants. They looked nice at first, and continued to get flowers; however, they grew quickly, and after a while started to look lanky. Gradually, growth became less attractive, and leaves started to get black spots/blotches of mold on them. I removed the plants and planted native Cocoplum shrubs (Chrysobalanus icaco); however, seedlings from the removed S. urticifolia shrubs kept popping up! They reseed plentifully.

Also, S. urticifolia is now listed as a Category Two Invasive by the Florida Exotic Pest Plant Council for central and southern Florida.

NOTE - I am giving this plant a neutral rating because it still has it's benefits and, especially if given lots of maintenance, can look really well.

A woody perennial here in Central Florida (zone 9a) -- mine is 4'X2.5', after a heavy prunning in February. Grows in partial sun (morning sun, 3 hours or so) and full sun. Low water needs, and I've never fertilized mine. Leaves are pinnate, serrated, pleasant dark green. Year-round flowers, although upper part of plant browns in cold weather. Blooms are tiny on sometimes very long (18") "rat tail" panicles. Self-sows fairly prolifically, but the seedlings are easy to identify, dig up, and transplant. Also very easy to propagate from cuttings. I can't say it's a stunning flower, but hummers and butterflies and bees all love it, and it's very low maintenance.

Definitely attracts butterflies. My monarch caterpillars like to form their pupas under the leaves. Very, very pretty plant.

One of the most prolific flowering shrubs here in Costa Rica
How anyone could think it 'weedy looking' I would disagree with! Both butterflies and hummingbirds abound! Very often grown a a hedge.

This is one of premier butterfly plants in southwest Florida. It is kind of weedy looking, however, so you may not want it anywhere except in a butterfly garden.

I have all kinds of salvia's sages and other hummingbird plants but the porterweed seems to be the most popular with hummingbirds in my East Texas garden.

The dark blue porterweed (Stachytarpheta cayennensis) is a great addition to any butterfly plant. This plant can seed a little too freely so give it lots of elbow room.

There is a pink variety of this plant which can grow rapidly to 12' and puts out quite a show. The soft wood can get wind whipped and break off in storms very easily but it quickly grows back again.