Knotweed is considered a worldwide invasive weed. It has a strong ability to compete with other plants for water, nutrients, and sunlight. Most importantly, knotweed pollen can easily trigger hay fever and bronchial asthma, posing a serious threat to human health. Now let's learn about the growth habits and hazards of knotweed.
Knotweed image
[Growth Habits of Knotweed]
1. Strong Regenerative Power
Stems, nodes, branches, and roots can all grow new roots. After cutting and planting, new plants can be formed. The growth period is uneven and overlapping.
The emergence period starts from mid-late March and can last until late November for a total of 7 months. Early and late maturing knotweeds have a difference in growth period of over a month. This is the direct cause of the uneven and overlapping growth periods.
2. Likes Moisture, Dislikes Drought
Knotweed is a shallow-rooted plant and cannot absorb water from deep soil layers. It commonly withers and dies during the dry season in late autumn, while knotweed growing in moist areas thrives.
3. Strong Cold Resistance
Mature knotweed can withstand temperatures as low as -3 to -5℃, making it a perennial knotweed. It grows densely in patches. Since knotweed fruits generally scatter on the ground within a radius of 1-1.5m around the plant, year after year, it forms a densely growing population.
Knotweed image
[Life Cycle of Knotweed]
1. Seedling Stage
The germination rate of knotweed seeds is 91.49%. The highest, best, and fastest seedling emergence rate is from seeds that are planted 0.3-1cm deep in the soil, while those over 5cm cannot emerge.
2. Branching Stage
This stage is actually the period of branch and leaf formation, with vertical growth as the main focus. When the vertical growth tends to stagnate, the formation of branches and leaves also ends. From late April to late July, over 100 days in total.
3. Flowering Stage
The male flowers take 65-70 days, while the female flowers take 50-55 days. This period is mainly characterized by horizontal growth of the crown. From July 31st to September 30th, the growth rate of the crown is 5.5-5.8 times faster than the vertical growth. At the same time, the stem and branches thicken and extend rapidly, and the flower organs mature faster.
4. Fruit Ripening Stage
The time when a large number of fruits mature is in early to mid-October, with a ripening period of about 20 days. The ripening pattern of the fruits is the same as the formation pattern of the flowers, from top to bottom and from outside to inside.
Knotweed image
[Hazards of Knotweed]
Knotweed has the ability to consume more water and nutrients than field crops and cereals, causing serious yield reduction or even complete crop failure.
Knotweed pollen can trigger hay fever and bronchial asthma, posing a serious threat to human health.
Knotweed pollen has caused millions of people in the United States, the Soviet Union, the United Kingdom, and Japan to suffer from hay fever and allergic asthma, with severe cases almost life-threatening.
As a malignant weed, knotweed also shows strong vitality and high reproductive capacity. A single knotweed plant can produce thousands of seeds, which can be spread everywhere by wind, humans, livestock, birds, and water flow. Breaking knotweed will result in the growth of more new branches from the remaining roots.
There are three methods to eliminate knotweed. From late May to mid-June each year, before knotweed blooms, it can be uprooted and burned. This method is simple, effective, and thorough.
If a large area of knotweed is found, a 10% glyphosate herbicide can be sprayed, with a kill rate of over 90%. In addition, the Soviet Union uses a specific beetle species for control, while the United States uses a white rust fungus method.
