Plants having red stems are common in many Vascular plants even though their leaves maybe green.
In some plants, the red pigment is restricted to internodes or the nodes only as the case may be.
Red coloration may also develop in otherwise green stems in response to abiotic stressors such as drought, low temperature, ultraviolet radiation, etc.
The pigment responsible for red coloration in most herbaceous species is Anthocyanins.
1. Castor Bean
The Ricinus Communis or the castor bean is a fast-growing large perennial shrub flower,
It belongs to the spurge family Euphorbiaceae, it is grown for commercial use and is mostly used in the pharmaceutical and industrial use for its oil, and it can also be used for landscaping
The plants are cultivated chiefly in China, Brazil, and India, it is the only plant in its genus.
The oil-rich seed contains poison ricin and it is one of the most toxic known substances and consuming the seed can be deadly.
Its seed is the castor bean, the castor seed is used in making castor oil which has a wide variety of uses. It is a fast-growing suffering shrub that can reach the size of a small tree but it is not cold hardy.
It has glossy leaves that are 15-45cm long, long-stalked, alternate, and palmate with five to twelve deep lobes with coarsely toothed segments.
In some varieties, the plants start with dark reddish-purple or bronze when young and as they mature, they tend to grow greenish with a tinge of red. The stems also tend to vary in pigmentation.
2. Pokeweed (Phytolacca americana)
The Pokeweed is a hardy perennial herb found commonly growing in the southern region of the united state,
It has a pretty magenta stem with purple berries. The pokeweed grows 4 to 10 feet, it has simple green leaves to red or purplish stems and a large white taproot.
It is native to Eastern North America, the Midwest, and the south.
The pokeweed plant is poisonous to humans, dogs, and livestock, the leaves and shoots are edible with proper cooking during early summer.
It is used as an ornamental plant in many horticulture and it provokes interest in varieties of its natural products.
Here is an article I wrote on plants with parallel leaves
3. Himalayan Balsam
The Himalayan Balsam is a large annual plant native to the Himalayas,
It is present across much of the Northern Hemisphere and it is considered an invasive species in most areas.
The effective means of controlling this plant is by cutting and uprooting the plants.
It is an herbaceous, terrestrial, and annual plant that thrives in wetlands, forests, gardens, etc.
The plants compete heavily with native species and alter the behavior and composition of pollinating insects.
The plant grows between 3 to 6 feet tall with red and purple stems that are hollow and smooth, on each stem, there are 5-10 flowers and 5 petals per flower, purple, pink, or white, when ripe, the fruit capsules explode when touched.
4. Wine Berry (Rubus phoenicolasius)
Wine Berry is an Asian species of raspberry in the Rose family,
It is native to Korea, China, and Japan, but was introduced to Europe and North America as an Ornamental Plant.
Wineberries have silvery underleaves just like the raspberry, a fruit core that remains on the core when the fruit is picked and thorns.
The only difference is that wineberry has fine red hairs that grow densely along its stems and flowers giving the plant a reddish hue.
Wineberry has vitamin c, fiber, minerals, and antioxidants.
5. Common Purslane (Portulaca oleracea)
The common Purslane is an annual succulent plant belonging to the family Portulacaceae.
It reaches 40cm in height, some human cultures have eaten this plant as a nutritious herb throughout history.
The common Purslane has a smooth reddish mostly prostrate stem and leaves which may either be alternate or opposite.
The flowers are yellow, have five regular parts, and are up to 6mm wide, the flowers can appear during any given time of the year depending on rainfall.
They are used mainly for culinary purposes and can be eaten as leaf veggies.
6. Elephant Bush (Portulacaria area)
The Elephant Bush is a small-leaved succulent plant that is found mainly in South Africa.
These plants have reddish stems and green leaves. They are simple to grow and care for and make easy houseplants for a Sunny location.
The plant might be used for outdoor landscaping in frost-free regions.
It is a soft-wooded, semi-evergreen upright shrub or small tree, usually 2.5-4.5m tall,
It is hardier, faster-growing, more loosely branched, and has more limber tapering branches.
It is most rare in moist climates and tends to favor dryer rocky outcrops and slopes.
Also check out this article I wrote on plants that protect vegetables
7. Lady’s Mantle (Alchemilla Vulgaris)
The Lady’s Mantle is a genus of herbaceous perennial plant in the family Rosaceae,
The plant is used as a herbal tea or medicinal usage to treat gynecological disorders, there are about 700 species of this plant with the majority being native to cool temperate and subarctic region of Europe and Asia.
Most species of the Lady’s Mantle are mounded perennials or clump-forming arising from woody rhizomes.
It has reddish stems typically fan-shaped with small teeth at the tips, the leaves are covered with soft hair and show a high degree of water resistance.
8. Red Stem Thalia
The Red Stem Thalia has a dainty spike of violet flag-like flowers at the end of the stems in mid-summer that emerges from distinctive deep purple flower buds.
It has bluish-green leaves with distinctive chartreuse veins throughout the year.
It has an attractive red stem and in the summer months produces lavender flowers produced high above the foliage during the summer month.
The red stems are either streaked or solid, this stem contrast nicely with its leaves.
9. Pigweed ( Amaranth)
The pigweed is a cosmopolitan genus of annual or short-lived perennial plants collectively known as Amaranth,
Some of them are cultivated as vegetables and ornamental plants, while other species are common summer weeds and are known as pigweed.
They vary in flower, leaf, and stem colors with a different range of striking pigments ranging from a spectrum of maroon color to crimson and grow from 1 to 2.5m.
It is tall with a cylindrical, succulent, fibrous stem that is hollow with grooves and bracteoles when matured.
The Amaranth or pigweed is a herbaceous plant or shrub that is either perennial or annual across the genus.
The leaves are oval and of elliptical shape that is either opposite or alternate across species, although most leaves are whole and simple with entire margins.
10. Mountain Pepper (Tasmannia lanceolata)
The Mountain Pepper is a shrub native to the woodlands and cool temperate rainforest of South-Eastern Australia.
The shrub varies from 2-10m high.
The leaves are aromatic and are lanceolate to narrow-elliptic or oblanceolate,
The leaves are 4-12 cm long and the width is 0.7-2.0cm wide with distinctly pale undersurfaces.
The stems are red with small cream or white flowers appearing in summer and are followed by black, globose, etc.
The plants are separated into female and male.
The leaves and berries of the plant are used as spices when they are dried.
It is used as a substitute for winter’s bark, a stomachic, and it is also used in the treatment of scurvy.
Plants having red stems are a common occurrence most especially in vascular plants, in some cases the red stem may be restricted to internodes or the nodes only as the case may be.
There are many varied reasons why your plants have red coloration and some of these reasons may be natural or a result of drought or low temperature or ultraviolet radiation.