Monday, May 30, 2011

Better Know an Invasive Plant: Japanese Knotweed

Japanese knotweed is an herbaceous perennial that can reach a hight of up to ten feet. It is often found near freshwater ponds and streams but can be found all over my neighborhood in yards and by roads. It develops from stalks close to the ground in early spring and by late spring/early summer is usually very noticeable in dense thickets.

Japanese knotweed is easily identifiable by its red stems:

and broad, somewhat shovel-shaped leaves:

Like most invasives, Japanese knotweed was introduced intentionally probably sometime during the 1800s. It has been used ornamentally in the Northeast United States and more recently was used for erosion control in the Northwest United States. Using non-native plants as erosion control in areas where native plants have been wiped out is an ongoing practice. Though I will assume that people making these decisions for the DCR or like organizations have done their research it still seems like a troubling practice with the knowledge of how much invasive plants have changed our local ecosystems.

Japanese knotweed is also edible and contains many valuable nutrients including vitamins A and C, zinc, phosphorus and manganese. It also contains the compound resveratol which is also found in the skin of grapes used to make red wine. This compound is what gives red wine its cholesterol-lowering properties. Research on resveratol is ongoing and many believe that it may be useful in fighting Alzheimer's and possibly even extend life expectancy.

As usual the best thing you can do to help the spread of Japanese knotweed is to try getting rid of it if you see it on your property. Most infestations can be removed manually if one is sure to remove the whole plant and bag and dispose of all parts efficiently. You may also want to encourage your neighbors and local parks managers to be on the lookout for Japanese knotweed because it can recolonize disturbed areas very quickly (are we seeing an invasive plant trend?).

Friday, May 27, 2011

Taraxacum officinale

Most people consider the common dandelion a weed. I can't decide how to feel about it, honestly. It is technically non-native but whether or not to call it an invasive is tough. Like all "weeds" and "invasives" it is remarkably good at colonizing disturbed soil. It can even reproduce asexually making it somewhat resilient to a decline in pollinators. That being said, it is a small, fairly unobtrusive perennial. Dandelion patches never reach the magnitude of say, garlic mustard or Japanese knotweed. And, while this can be said of several invasives, its greens are a nutritious food.

I think the main reason that I can't decide how to feel about this non-native is that our modifications of the landscape are the primary reason for its success. Without lawns and sidewalks this perennial would not be seeing the success it has today. With leaves that stay in rosettes just on the ground it quickly gets shaded out by taller plants so it needs a wide open, sunny space to grow.

If you do want to get ride of dandelions your options are pretty much herbicide alone; its hearty taproot can survive even the most rigorous gardeners.

Saturday, May 21, 2011

Podophyllum peltatum

Mayapple is a native perennial found in the eastern United States from about Minnesota/Texas to the coast. They are found in wooded, shaded thickets and grow best in moist soil. The plants grow and flower late April to early June. The single flower becomes an edible, though not particularly tasty, fruit.

The plant is actually mildly toxic all over but the highest concentrations of the toxic compounds are found in the rhizomes (root-like stems). These compounds have traditionally been used in herbalism but western science has also transformed them into useful cancer-killing drugs.

Despite its toxicity the mayapple fruit is used to make jams and jellies. Deliciously irritating!

Sources: Kaczmarek, Frank (2009). New England Wildflowers. Guilford, CT: Falcon Guides.

Alternative Nature Online Herbal:

Friday, May 6, 2011

Better Know an Invasive Plant: Garlic Mustard

Garlic Mustard is a plant native to Europe that can be found virtually everywhere now in the Eastern part of the United States. I had to go about two blocks from my house before I found these garlic mustard plants. There's another little patch of them growing out of a rock wall just a little further down that same street. Like other invasive plants it is problematic because it out-competes and shades out native plants that are important for native insects, browsers and pollinators. Because garlic mustard is generally about two to three feet high it is a problem for native ephemeral flowers, some of which do provide foods to insects.

This can also be harmful because having too much of one plant in an ecosystem is generally a bad thing. Ecosystems thrive on variety. The more complex a food web is the more robust and stable it will be so when an invasive comes in and out-competes, say six species, the complexity of the ecology, and therefore it's overall health, is reduced.

You can recognize garlic mustard on your land by its heart or triangular shaped leaves and small clusters of white flowers. In the first year the plant remains close to the ground in a rosette of leaves. If you find a few plants you can pick them, making sure to take the entire root structure. If you find a more severe infestations the plants can be cut in early May just after flowering to prevent them from going to seed. If a very sever infestation is found herbicide is generally the only choice.

Like most invasive plants in the US garlic mustard was intentionally transported by humans from Europe. It does have both culinary (a garlic flavor, hence the name) and potential medicinal uses. Despite the potential uses it is not recommended that anyone cultivate this plant because it does present a fairly extreme threat to native ecology.

Monday, May 2, 2011

Chrysemys picta picta

I've been trying to catch up on a year-old Earth Day resolution (happy belated Earth Day, by the way) to help educate my readers about invasive plants. While spring is certainly here most of the plants I found were still in the middle of leafing out so photographing them is going to wait a week or two longer. Instead I managed to find and photo some vertebrates. One of the only reptiles you'll easily find in Massachusetts is the Eastern Painted Turtle:

I actually spotted 15 turtles at the pond today. You can see a variety of sizes from a full grown adult here on the right, two small turtles (probably about a year) and a mid-sized juvenile at the left. Just like all reptiles these turtles are sunning themselves. Unlike mammals like us they have to get heat energy directly from the sun. I was really happy to see so many turtles today because it is a sign the pond is fairly healthy and not being overrun by introduced predators like dogs and cats. No amphibians though, which isn't a great sign.

Painted turtles are so called for the "painted" yellow stripes on their heads and chins:

This image had to be blown up a bit so it doesn't have the best resolution, but you can clearly see the yellow stripes. Most semi-terrestrial turtles like these go pretty far to build there nests but these turtles stay close to water. The nest is a few inches deep and generally has a little water at the bottom while the eggs develop. This may be the reason these turtles seem to do fine in a pond right in the midst of several busy Boston roads.

The Eastern Painted Turtle is sometimes confused with the extremely endangered Red Bellied Cooter which are found primarily in Plymouth County, MA. Many organizations "head start" these turtles, collecting them when they are just hatched (and at perfect snack size for predators) and then releasing them about a season later when they are big enough to stay safe. These turtles are distinguishable from Eastern Panted Turtles by a slightly different size and head markings.