Knotweed 2 - Idenfication, Reproduction and Spread of Japanese Knotweed





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Published on Nov 22, 2013

An introduction to Japanese Knotweed, the problems it causes and what to do about it, Part 2 of 3.

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Chances are you've met before. It seemed nice. Green, lush...even beautiful. Don't be fooled. It's an invasive alien invader... and we are about to blow its cover.

Knotweed uses a number of aliases. False bamboo, Japanese bamboo, Japanese fleece-flower, wild rhubarb -- to name a few.

It takes on a number of forms to elude identification. When it first emerges in the spring, Knotweed looks like pink asparagus poking out of the ground. As it grows it can often be misidentified as small cottonwood tree seedlings. Continuing to grow rapidly, it reaches its full height of up to 3 meters. At this stage it looks similar to bamboo with its tall, hollow, segmented stems.

Late in the growing season, it has large green, heart-shaped leaves and some plants will produce small white flowers. As fall begins, Knotweed begins to die back for the winter and the leaves turn yellow like trees. Finally, the leaves drop, leaving behind tall, brown, hollow, woody stems. In the spring, the cycle of identities begins again.

Not only do Knotweed stems grow quickly, they also increase in numbers at an alarming rate. As its extensive underground network of roots grows, new shoots are sent up. The plant continues its offensive throughout the growing season, causing a small infestation to expand quickly into large one -- if left unchecked.

This cunning alien invader assures its continued survival by spreading easily using multiple strategies. Like many plants, Knotweed can spread by seed. But with only a small percentage of seeds being viable, Knotweed prefers to expand its territory by a much more diabolical means: by small pieces of its stems and roots. In fact, a single fragment containing the red segment, or internode, can result in the growth of an entire new plant!

Knotweed bits travel quickly and efficiently: catching a wave down a stream; blowing in the wind; riding on birds or animals; transported by lawn mowers, weed whackers, and infill... it doesn't take much for this plant to get around.

But perhaps Knotweed's best strategy is to take advantage of the unsuspecting gardener. After all, something green can't be this bad, right?

Wrong. That's why awareness is our best defense -- and if Knotweed has invaded your property, correct knowledge is vital. Before you prepare a counterattack against Knotweed, learn about your nemesis and arm yourself with the facts.


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