After getting several cuttings of porterweed from Mary, a guest gardener, I found the plant itself at a local nursery last year. This year, it's doing great. In January, I pruned it back severely because the plant will grow so very tall. This is a tropical plant that will not only soak up summer's heat, but will entice hummingbirds and butterflies to the garden. Considered a weed by some and an ornamental plant by others, it is referred to as a "pantropical weed" that is native to both subtropical and tropical regions.
The leaves are attractive, crinkled and toothed. The flowers are small, about a quarter-inch in diameter, opening along spikes. What turns the tide toward it being an ornamental plant is the blue variety. This plant has the lovliest rich blue color. I don't have a blue porterweed at the moment, but I found a picture that will give you a hint of what we're talking about here.
Porterweed is a prolific bloomer and it attracts a wide variety of butterfly. They all flock to drink its sweet nectar. You can plant porterweed in a dry, sandy area without fertilizer and it will stay small, growing about three feet in height. If you improve the soil and fertilize the plant, the flowers will be much larger, growing on thicker stems and the plant may grow to over five feet tall. The flower spikes can be as long as 10 inches.You can keep your porterweed whatever height you wish with pruning. During the hot months, it will rebloom quickly after been cut back. And, it's remarkably easy to propegate. Stick any part of the plant into the ground and it will root in two or three weeks.