Ageratum conyzoides, a member of the Asteraceae family and the Ageratum genus, is an annual herbaceous plant lacking a prominent taproot.
The stem is robust, measuring 4 millimeters in diameter at the base, with branches that are pale red or green with a white, dust-like short pubescence on the upper part. The leaves are opposite, with ovate or oblong blades.
The inflorescence of Ageratum conyzoides is corymb-like, with the involucre bell-shaped or hemispherical and the bracts oblong or lanceolate-oblong.
The corolla is pale purple, about 1.5-2.5 millimeters long, hairless or with dust-like micro pubescence at the tip. The achene is black-brown, and the flowering period is from July to December.
Native to Central and South America, Ageratum conyzoides has spread widely as a weed throughout Africa, India, Indonesia, Laos, Cambodia, Vietnam, and China.
It thrives in warm, sunny environments with no strict soil requirements and is intolerant to cold and poor growth in extreme heat.
It is commonly found in mountain valleys, forest edges, riverbanks, grassy slopes, fields, or wastelands, and is typically propagated by seeding or cutting.
With its delicate flower color, Ageratum conyzoides is often used for flower beds and ground cover, suitable for small gardens, roadside beautification, and rocky areas.
It serves various landscaping purposes, including flower beds, potting, ground cover, flower borders, embellishing lawns, and as a ground-covering material.
Medicinally, it is used to treat diseases such as spurge hawkweed, sore throat, diarrhea, kidney stones, eczema, thrush, carbuncles, leg ulcers, otitis media, and traumatic bleeding. As of January 1, 2023, Ageratum conyzoides has been included in a catalog of key managed alien invasive species.
The Ageratum conyzoides, a one-year herb of the Asteraceae family, typically grows between 50-100 centimeters tall, sometimes less than 10 centimeters, with no distinct taproot.
The stem is robust, 4 millimeters in diameter at the base, sometimes slender, and may branch from the base or middle, or the lower part may lie prostrate, often with adventitious roots at the nodes.
All the stems and branches are pale red or green on the upper parts, covered with white, dust-like short pubescence or dense, long villous hairs.
The leaves are opposite, sometimes alternate at the upper parts, often with underdeveloped axillary buds.
The middle stem leaves are ovate, elliptical, or oblong, 3-8 centimeters long and 2-5 centimeters wide; leaves gradually decrease in size from the middle towards the top and bottom, and those on the axillary branches may be even smaller.
All leaves have a blunt or broadly cuneate base, with three or indistinctly five veins emanating, acute tips, and serrated edges.
They feature a petiole 1-3 centimeters long, covered sparsely with short white pubescence and yellow glandular dots, with slightly more hairs along the veins on the upper surface and sometimes nearly hairless on the underside.
Petioles of the upper leaves and those on axillary branches tend to be densely covered with white, spreading long soft hairs.
The capitate inflorescences, 4-18 in number, are arranged in dense corymb-like clusters at the stem apex; the inflorescence diameter is 1.5-3 centimeters, occasionally arranged in a loose corymb.
The peduncles are 0.5-1.5 centimeters long, covered with dusty short pubescence. The involucre is bell-shaped or hemispherical, 5 millimeters wide.
The involucral bracts are in two layers, oblong or lanceolate-oblong, 3-4 millimeters long, hairless on the outside, with fringed margins. The corolla is 1.5-2.5 millimeters long, hairless or with dust-like micro pubescence at the tip, and the limb is 5-lobed and pale purple.
The achene is black-brown, pentagonal, 1.2-1.7 millimeters long, sparsely covered with white fine soft hairs.
There are 5 or 6 pappus scales, oblong, tapering abruptly or gradually to a long or short awn, or some scales are truncated at the top without an awn-like taper; all pappus scales are 1.5-3 millimeters long. The plant flowers from July to December.
Branches and leaves:
The robust stems are 4 millimeters in diameter at the base, with pale red branches or green upper parts covered in white, dust-like short soft hairs; the leaves are opposite, with the blades being ovate or oblong.
Flowers and Fruit：
The inflorescence is cymose, with the involucre being bell-shaped or hemispherical, and bracts are oblong or lanceolate-oblong; the corolla is long, glabrous on the outside or with dust-like soft hairs at the apex, and pale purple; the nutlets are dark brown.
Branches and leaves:
Reaching 30-70 centimeters in height or sometimes up to 1 meter, with no prominent main root, all leaves have petioles that are 0.7-3 centimeters long, with pappus scales being membranous, 5 in number, separate, and either oblong or lanceolate.
Flowers and Fruit：
The capitulum consists of 5-15 or more flowers arranged at the ends of branches forming umbels or compound umbels 2-4 centimeters in diameter; the involucral bracts are in two layers of narrow lanceolate shape.
The corolla is 2.5-3.5 millimeters long, with a pale purple limb. The nutlets are black.
Native to Central and South America, Agastache rugosa typically grows in mountain valleys, under forest canopies or edges, along riversides or on grassy slopes, beside fields, or on wastelands.
As a weed, it has spread widely across the entirety of Africa, India, Indonesia, Laos, Cambodia, Vietnam, and China, from low altitudes up to elevations of 2800 meters.
Prefers warm and sunny environments with no strict soil requirements. It is not cold-hardy and does not grow well in extreme heat. It has a strong branching habit.
Commonly reproduced by sowing seeds and cutting.
The seeds of Agastache rugosa are small and require meticulous sowing. Generally, seeds are sown indoors in greenhouses at the beginning of February or outdoors in early April.
The potting mix should be half farmyard manure and half garden soil, with a small amount of leaf mold mixed in evenly after sieving. For limited seedling cultivation, pots can be used (for large-scale cultivation, seedbeds are appropriate).
Fill the pots with potting mix, compact it, and water thoroughly. Once the water has drained, scatter the seeds evenly over the moist soil. Cover the seeds with a thin layer of soil, just enough to conceal them.
Keep the soil moist. Seedlings typically emerge around 10 days later. When the seedlings display two sets of true leaves, they should be pricked out into small plastic pots, one plant per pot.
For earlier shaping and flowering, cuttings are used for propagation. Prepare a large parent plant by keeping it in a greenhouse over winter. In early spring, take healthy cuttings, preserving 2-4 true leaves but not the growing tip.
The cuttings should be 5-6 centimeters long, with the cut made just below a node. Insert the cuttings to a depth of one-third to one-half of their length. During the hot season, place the cuttings in a cool, shaded area to prevent damage from high temperatures and sunlight.
Roots should form in about 10 days, and then the cuttings can be separated. Cuttings can be taken during any growing season except for the cold of winter and are easy to root.
Mexican sunflower seedlings are ready for potting when 2-4 branches have developed. Plant one seedling in a 4-inch pot, using a soil mix of equal parts manure, garden soil, and fine sand, sifted together.
After planting, compress the soil firmly, water thoroughly, and place in a shaded area. After 7-10 days, move the pots to a sunny location. At this point, the seedlings will have acclimatized and normal growth begins.
Pay attention to water and fertilizer management: water when the surface soil turns pale and dry, ensuring each watering is thorough, avoiding partial watering.
During the high-temperature season, which is the peak of growth, water twice daily. Fertilize every 10-15 days with diluted cake fertilizer water, and increase phosphorus and potassium fertilizers appropriately.
This will result in compact plants with numerous, vivid blooms, enhancing their ornamental value.
Mexican sunflower has a long flowering period. To maintain a short, compact shape, and ensure the beauty of its abundant flowers, it’s necessary to pinch the plant 3-4 times.
To achieve a rounded shape with all branches ending in flower buds blooming simultaneously, creating lush foliage and vibrant flowers, pinch the plant several times.
After the first wave of blooming, prune timely, generally keeping the old branches at a height of 5-6 centimeters, trimming off the top and thinning out dense branches.
Then, ensure adequate water and fertilizer to encourage the sprouting of new branches, keeping the foliage green and flowers vibrant.
Preferring moist or semi-arid climate conditions, Mexican sunflower requires an ambient air temperature of 50-70%. If the air is too dry, the lower leaves may yellow and fall off, and the upper leaves lose their luster.
Originating from subtropical regions, Mexican sunflower has strict temperature requirements during the winter, ceasing growth when environmental temperatures fall below 8°C.
It has a strong adaptability to light. When kept indoors, place it in a brightly lit area, such as a well-lit living room, bedroom, or study.
After being indoors for a while (about a month), move it outdoors to a shaded area (with winter protection) for another month or so, alternating like this.
Mexican sunflower is not frost-hardy. Before the onset of frost, move it indoors to a sunny spot. Nighttime temperatures should be above 5°C, and daytime temperatures between 10°C-15°C for normal growth and flowering.
Water every 3-5 days, and apply diluted cake fertilizer water every half month.
Root rot, rust disease, cutworms, and whiteflies are common afflictions. For root rot, apply a solution of 10% antibacterial agent 401 diluted to 1/1000th with acetic acid.
For rust disease, use a solution of 50% rust-preventing fungicide WP diluted to 1/2000th. Pest infestations can be addressed with a solution of 90% Dichlorvos EC diluted to 1/1000th for spraying.
Agastache rugosa, with its soft and elegant flower hues, is frequently used in flower beds and as ground cover.
It can also adorn small gardens, roadside areas, and rocky landscapes, serving as material for flower beds, potted plants, ground cover, garden borders, ornamental lawns, and ground cover.
The lush clusters of Agastache rugosa, known for their soft and elegant colors, are ideal for flower beds and ground cover, and can also embellish small gardens, roadside spots, and beside rocks.
Dwarf varieties are excellent for potted display, while taller types are suited for cut flowers in vases or for crafting flower baskets. They are used for flower beds, potted plants, ground cover, garden borders, ornamental lawns, and as ground cover material.
Agastache rugosa is employed in treating scrofula, sore throat, diarrhea, kidney stones, eczema, thrush, carbuncles, lower limb ulcers, otitis media, and external hemorrhage.
In Africa and the Americas, the whole plant is used for its heat-clearing, detoxifying, anti-inflammatory, and hemostatic properties. In South America, locals highly regard its use for treating non-uterine hemorrhage in women.
The entire plant is pungent and slightly bitter, with cooling properties. It’s used for dispelling wind, clearing heat, relieving pain, stopping bleeding, and promoting stone expulsion.
It is indicated for scrofula, sore throat, diarrhea, stomachache, uterine bleeding, kidney stones, eczema, thrush, carbuncles, lower limb ulcers, otitis media, and external bleeding.
The flower language of Agastache rugosa conveys “affection” and it is the guardian flower for Scorpio and the birthday flower for those born on August 14th.
Peggie was once a high school mathematics teacher, but she set aside her chalkboard and textbooks to follow her lifelong passion for flowers. After years of dedication and learning, she not only established a thriving flower shop but also founded this blog, “Flowers Library”. If you have any questions or wish to learn more about flowers, feel free to contact Peggie.
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