Undesirable Plants

God's Warrior · Undesirable Plants

Undesirable Plants

Maybe you can add to this list by telling us about plants that you think are undesirable in your own gardening situation.

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Pennyroyal, Mentha pulegium, aggressive invader and a non-native mint - a dicot in the Lamiaceae family
Common names: squaw mint, tickweed, stinking balm, mosquito plant.

This is a pungent herb. Its groundcover-like growth habit changes dramatically in May, when the square bloom stalks appear, growing to 24". It also looses its reddish hue as the temperatures rise. Light blue to light lilac colored flowers form whorls along the main stem, very similar to horehound. The dried flower stalks often persist in the landscape through the winter.

Pennyroyal has a groundcover growth habit with a reddish hue to the leaves in wintertime. Pennyroyal oil is a "highly toxic oil, used mostly as a pesticide." It can kill "if less than a teaspoon is ingested." Pennyroyal is used as a household ant and flea repellent.

WARNING: Causes internal bleeding and death if ingested as a tea or oil.

Carol7
I remember seeing pennyroyal for sale in the herb section of a small nursery in Pennsylvania. After reading this post it will be the second time this year I've seen an undesirable plant for sale at a nursery.

This spring I saw some Imperata (Japanese Blood Grass) cylindrica 'Red Baron'. It caught my eye because it was an interesting looking grass. The ones they had were already sold and the owner said he was having problems getting more of it. I did a web search to see if I could locate any and instead I found it was the last thing I wanted in my garden! In fact, in some states it is restricted.
I think this could be a very informative thread for all of us.

Aloe
A good percentage of what we now consider weeds are not native to this country and were brought here because they had medicinal or other practical uses at that time. These plants thrive under garden or agricultural conditions, and thus they are weeds for us. What I find interesting is that I get some of the same weeds in my garden here as I saw back in Pennsylvania.

Though a lot of weeds do best under human-altered conditions (gardens, roadsides, vacant lots, etc.), some are really badly behaved and invade into the native wild vegetation, especially along streams. The California Native Plant Society has tried to forbid the sale in CA of some of these bad actors (pampas grass is a biggie) but to my knowledge, they have not been successful in getting any laws passed yet. Nursery stock is a big business in CA, so they probably have powerful lobby. (Surely it isn't going to kill anyone if they stop selling maybe dozen species.) The CNPS has also done a lot of physical work locally to successfully remove things like milk thistle, yellow star thistle, and ailanthus from state parks.

Carol, could you tell me more about the Japanese blood grass? From time to time I think that I would like to get some but never have because I am not sure if it would survive here. Maybe it would survive too well. The second-to-the-last thing I need in the yard is another invasive grass species.

Elena
Lets try to look up a few more plants that need to be avoided in our gardens. I know that they have had a terrible time here in TN with the two thistles you mentioned. Maybe you two can do a little research on the matter also. It would be good to create a little list of plants that we need to avoid instead of being sorry later.

Carol7
Aloe, http://www.floridata.com/ref/I/impe_cyl.cfm
has good info and if you do a yahoo search for japanese blood grass 'red baron' a pdf file from the University of California at Davis will be the first one listed. It is also very informative. Between the two I believe they will answer most, if not all, of your questions concerning this plant better than I could.

I've seen this grass listed in a wholesale catalog, but at least they indicated it was restricted in some states - they don't list which states though. What bothers me is if someone is on a long vacation, stops at a nursery, and decides to bring this grass home to place in their garden. Even worse is that a nursery would sell it in this area without doing their homework first!

Pampass grass is popular with some folks here - they usually place it at the end of their driveways. (It's pretty to look at but I will never have it in my yard.) After a few years they regret they ever bought it.

Elena
Thanks Carol. I think it might be good to list the ones we find to be really undesirable and then I can go back and put the entire list in that first post of this thread.

Elena
I think the invasive ones would be the most likely choice for us gardeners. Don't you? We can get rid of the ones that aren't invasive much easier. Wild violets would have to fall in the list of most hated plants for me. I fight a never ending battle with those babies. They will just take your beds if you aren't on the ball constantly.

Carol7
I also have a problem with wild violets in my yard/garden. A friend of ours grows them in his flower beds because he says they control the other weeds. Whenever I see any I dig them up and get rid of them because they are of no help to me.

We also have wild petunias growing here. Although they are very pretty they try to take over too.

Elena
Actually, some morning glories can do the same thing. They wind up coming up everywhere.
Thanks for that link about the blood grass. I am glad to have a picture of it just in case someone offers me a start. I always like to know the plants that are real nusiences before falling victim to their trying to take over my beds. I guess if I have any one plant that tries to take over the most, it is those wild violets. No way would I ever cultivate those babies. I HATE THEM!!!! The seeds spread so rapidly and before you know it, they have taken over the lawn and the beds. I have see whole yards covered with them in our region. Needless to say, the home owners just gave up and let them take over.

Carol7
It sure is an eye-catching grass, isn't it? If there had been a pot of it available I would have bought/planted it, so there must have been an angel sitting on my shoulder that day. Very Happy