Ageratum houstonianum, Blue mink, Floss flower, Mexican paintbrush

Ageratum houstonianum, commonly known as blue mink, floss flower, blueweed, pussy foot, or Mexican paintbrush, is a cool-season annual plant belonging to Asteraceae / Compositae (Aster family) often grown as bedding in gardens. The plant is native to Southeastern Mexico and Central America. It was brought to Europe shortly after its discovery. The species is reported as invasive in China, Taiwan, Mozambique, Swaziland, Tanzania, Zimbabwe, USA (Hawaii), Cuba, Peru, Australia, Fiji, French Polynesia, and New Zealand. Few of the well-known common names of the plant include ageratum, billy goat Crofton, billy goat weed, blue billy goat weed, blue top, blue mink, blue top, dark blue top, floss flower, floss flower, garden ageratum, goat weed, invading ageratum, Mexican ageratum, Todd’s curse, tropic ageratum, blueweed, pussy foot and Mexican paintbrush.

Genus name apparently comes from the Greek meaning not and geras meaning old age because the flowers hold their color for a long time. The plant is sometimes harvested from the wild for local medicinal use. It has been reported that A. houstonianum has broad biological activities, including antifungal, antibacterial, and antimicrobial activities. It has been used for treating pain? and infections, especially for healing of external wounds and skin diseases. However, the active component of A. houstonianum and its mode of action for curing skin wounds have not been investigated.

Bluemink Facts

Plant Description

Bluemink is a short-lived, cool-season, erect, herbaceous annual or dwarf shrub that normally grows about 10 to 70 centimeters tall. The plants usually grow to a width of 10 to 30 centimeters. The plant is found growing in gardens, roadsides, disturbed sites, waste areas, pastures, crops, wetlands, waterways, farmlands, forest trails, riverbanks, cleared upland slopes, crests, pine woods, cultivated ground, savannas, humid areas, riparian zones, pine woods, and coastal area. Well-drained soils are preferred with some added organic matter and a layer of mulch. It is sometimes cultivated and is often a weed in nursery stock. It can be found occasionally as an escape or weed in plant nurseries, in landscaped areas, and around disturbed urban areas such as parking lots or drainage ditches. It is a fibrous-rooted annual plant. Stems are simple or branched, erect or decumbent, reddish to green, glandular-villous to lanate above. The stem is covered in white, soft matted hairs (tomentose) or woolly hairs (lanate).

Leaves

The leaves are mostly oppositely arranged but can be alternately arranged on the upper parts of the stems. They are borne on stalks (i.e. petioles) 0.5-3 cm long and vary from being almost triangular in shape to egg-shaped in outline (i.e. ovate). These leaves are 2-7 cm long and 1.5-6 cm wide and have bluntly toothed (i.e. crenate) margins and either blunt or pointed tips (i.e. obtuse to acute? apices).  Both surfaces of the leaves and the leaf stalks have a scattered covering of hairs (i.e. they are pubescent).

Flowers

The flower-heads (i.e. capitula) are arranged in dense clusters at the tips of the branches (i.e. in terminal corymbs) and do not have any obvious petals (i.e. ray florets). Each flower-head is 5-8 mm across and has numerous tiny tubular flowers (i.e. tubular florets) that are surrounded by two or three rows of greenish-colored bracts (i.e. an involucre). The florets are 2-3 mm long and range from pale lavender to blue, pink, or purplish in color and each has two elongated projections (i.e. style branches). The bracts at the base of the flower-head is 3-5 mm long and are elongated in shape (i.e. linear-lanceolate) and covered in sticky hairs (i.e. glandular-pubescent). Flowering occurs throughout most of the year but more during June to October.

Fruit

Fertile flowers are followed by achene that are about 2 mm long, brown to black in color, and topped with five awn-tipped scales (i.e. a pappus). These scales are 2-3 mm long and are whitish in color and resemble short bristles or hairs. Plants are somewhat similar to our native Blue Mistflower (Conoclinium coelestinum, which is also occasionally called Wild Ageratum.

History

The plant is native to Central America in Guatemala and Belize, and adjacent parts of Mexico, but has become an invasive weed in other areas. It was also naturalized in large parts of the tropics and in the southern United States. Their habitat is pastures, moist forest clearings, and bushes up to altitudes of 1,000 meters (3,300 ft.).

Today, it is extensively used as an ornamental plant for summer borders and balcony boxes, high varieties also as cut flowers. The species is cultivated once a year, having numerous varieties whose crowns may be dark blue, purple, pink, and white.

Traditional uses and benefits of Bluemink

• The juice of the plant is used externally to treat cuts and wounds.
• The juice is used in folk medicine as an external wound healing aid for skin injuries.
• Weed has been used past time for its medicinal effect in numerous diseases such as common wound and the burned one, anti-microbe, arthrosis, pain? in the head or upper neck. সহজ বাংলা: মাথাব্যথা।" data-rx-term="headache" data-rx-definition="Headache means pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।">headache?, and dyspnea?.
• The infusion of its leaves helps to recover from muscle spasms and pain?, swelling?, stiffness?, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">arthritis? problems.
• It is also ideal to improve some digestive problems such as flatulence, diarrhea? or abdominal cramps.
• It is an effective reliever of menstrual cramps.
• Rheumatic pains are also relieved when the infusion is applied together with alcohol.
• Juice of the plant helps prevent infection? in wounds promoting rapid healing.
• In Ecuador, the plant is used to treat throat pain? or infection?, or irritation, often causing pain, swelling?, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation? in folk medicine.

Precautions

• Ageratum houstonianum is toxic to grazing animals, causing liver lesions.
• Parts of plants are poisonous if ingested.
• All parts of the plant are poisonous if ingested.
• Handling plants may cause skin irritation or allergic reaction.
• The plant has spines or sharp edges; use extreme caution when handling.
• Pollen may cause an allergic reaction.

References