Say "shrimp plant" to five gardeners and you're likely to get at least two, if not three or four or even five, different descriptions. To some, the shrimp plant will forever be the Pachystachys lutea, which is also known as the golden shrimp plant and is truly a beautiful plant. To others, the name is applied to one of the various Justicia species, especially the J. brandegeana. To make matters slightly more confusing, the J. brandegeana is also known as the Beloperone guttata. This plant features a, well, shrimpy colored flower bract that hangs from the stem tips. In their native environment, these plants grow up to six feet tall and have fairly brittle stems. Indoor growers, however, are more likely to trim their plant to keep it manageable and thus reduce its tendency to snap. Care for these plants is relatively uncomplicated, providing you can give it enough water and warmth.
- Light: Provide bright indoor light, but not full midday sun. They are perfect for atriums or other areas that are flooded with bright natural light.
- Water: They need plenty of water in the summer months, when they should never be allowed to dry out. Dry plants are more prone to leaf-drop. In the winter months, assuming you plan to keep it that long, cut the water back and don't let the temperatures get below 55˚F.
- Fertilizer: Feed weekly with a weak liquid fertilizer that includes micronutrients and encourages blooming. These are relatively high feeders and will respond well to amply fertilization.
- Soil: A light, fast-draining potting soil is perfect. You can use fortified soils.
These are relatively easy to propagate from stem-tip cuttings. To propagate successfully, take a cutting and dip it into rooting hormone, then place into a pot with seedling soil or a sterile rooting mix. The key to successful cuttings is to provide plenty of warmth and humidity, so aim to keep your cuttings at around 80˚F with high ambient humidity. Do not allow them to sit in water-logged soil.
Repot annually or every other year, depending on their growth rate. If you're growing in a large pot, you can move them outside to the patio during the summer, where they will likely grow much quicker and fill up their pots faster. At the end of the season, cut the plant back (you can cut these back almost all the way to soil and they'll spring back), then move it to its winter home. In the spring, repot when the first flush of new growth emerges. If you keep it indoors all summer long, you should only have to repot every other year.
There are hundreds of species of Justicia shrubs all over the world. The J. brandegeana species is originally from Mexico and has been popularized as a landscape plant through the southern United States. Although there is some confusion surrounding the naming of this plant, as long as you ask for a Justicia brandegeana, you'll be getting the right plant.
These plants benefit from a hard pruning every spring (no matter whether you grow them inside or out). Pruning encourages bushiness in the plant, and although this is unscientific, they have always bloomed more vigorously for me after a hard pruning. Well-grown specimens are typically provided with loads of water, fertilizer, warmth, and light. These conditions closely imitate their natural habitat, which is understory or transitional areas in subtropical climates. They are vulnerable to aphids and spider mites, so look for symptoms of infestation and treat immediately. Older plants are more brittle also, so be careful not to break stems (unless you're pruning). As a last note, there is some conflicting information out there about their temperature sensitivity. Personally, I have found that they are sensitive to temperature and will yellow or brown in temperatures below about 55˚F, especially in arid conditions. However, they will readily grow back as soon as the temperatures warm back up.