Last week I outlined three invasive terrestrial plants/shrubs that are growing wild here in our area. Plants that I am familiar with and have had to deal with on my property. This week, I present three more nasty buggers that seem to grow like mad even in the current drought conditions. Gosh, I wished my tomatoes and corn would grow like some of these invasive weeds. This week we will look at giant hog weed, buckthorn, and japanese knotweed.
It can tolerate a variety of adverse conditions including full shade, high temperatures, high salinity, and drought. It is found near water sources, such as along streams and rivers, in low-lying areas, waste places, utility rights-of-way, and around old home sites. It can quickly become an invasive pest in natural areas after escaping from cultivated gardens. What am I? Japanese knotweed, of course. Also locally known as japanese bamboo. This is one difficult plant to get rid of, for sure.
Brought here in the 1800's as an ornamental, the knotweed's minute greenish-white flowers occur in summer and are followed soon after by small winged fruits. Seeds are very small. It reproduces primarily by seed and vegetative means with the help of long, stout roots. It can be transported to new sites by water, wind, as a contaminant in fill-dirt, or on the soles of muddy boots, waders or shoes.
There was a study done by a group at Cornell a few years ago where they set box traps in amongst the knotweed. The results after a few months of trapping: Nothing! Seems that nothing lives in amongst the knotweed. At least no small mammals, reptiles or amphibians or anything else that could be caught in a box trap. So, if the small critters don't live there, it must stand to reason that there is nothing to eat in the "forest" of knotweed. I know from brush hogging it down that there are no other plants that grow in the amongst the denseness of a knotweed stand. And if you chop it down, it seems like it comes back with a vengeance.
Cutting by mechanical means only seems to control the knotweed. I know a fellow from Endicott that had success eliminating it by spraying glyphosate in EACH hollow stem that he cut. Another fellow here in Norwich had me cut it, rototill it under and then cover it with black plastic. He then added topsoil over the top of the plastic and had a knotweed-free garden. But this was on a small (50'x100') scale. Knotweed is a terribly persistent invasive with no real value.
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From my research, the giant hogweed plant has infiltrated Chenango County, but on a very small scale. The DEC information I was provided says that the plant has been eradicated here. But I am including it on my invasives list so that everyone can become educated about this terrible plant, and report it to DEC or the local health department if you spot it growing.
Giant hogweed is a perennial herb in the carrot family which can grow to 14 feet or more. Its hollow, ridged stems grow 2-4 inches in diameter, and have dark reddish-purple blotches, and its large compound leaves can grow up to five feet wide. Its white flower heads can grow up to 2 1/2 feet in diameter. To me it looks like Queen Anne's Lace on steroids, something you would see in a Jurrasic Park movie.
A native of Russia, it was introduced to the United States in the early twentieth century as an ornamental plant, and it has become well established in the Northeast. Hogweed grows along streams and rivers and in fields, forests, yards and roadsides. While it prefers open sites with abundant light and moist soil, it will grow in partially shaded habitats also.
While I have spoke of the non-beneficial elements to wildlife of the other invasive plants, the hogweed is more of a a health and safety hazard to humans, while it appears to have no benefit to wildlife. Its sap, in combination with moisture and sunlight, can cause severe skin and eye irritation, painful blistering, permanent scarring and even blindness. Contact between the skin and the sap of this plant occurs either through brushing against the bristles on the stem or breaking the stem or leaves.
Accordingly, if you find hogweed growing, it is recommended you report it by calling the Giant Hogweed Hotline: 1-845-256-3111. Providing photos, detailed directions to the plant infestation, and estimate the number of plants would be a big help. A site visit from DEC is likely. Because of its toxicity, there is a lot more to the eradication of hogweed than just knocking down the plant. Professional help is certainly recommended in eradicating this beast. Don't go it alone!
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I first came across common buckthorn on a friends property in Cattaragus County, out on the western end of New York State. This deciduous shrub grows to about 20 feet and spreads all over the place. The egg shaped leaves and thorns on the end of branches make it easily identifiable. The buckthorn grows small berries that are a dark purple, and the berries ripen during summer and can cling on to the plant well into winter.
