The Yellow Farmhouse Garden

September 5, 2019

Be careful not to introduce invasive plants into your garden

 

It’s surprisingly easy to introduce an invasive plant into your garden. It often happens when gardeners share plants with one another.

We have a few examples of that happening in our garden. One of those is Pinellia tripartita a plant native to China and Japan. I’ve heard it called Japanese jack-in-the-pulpit, although there’s another plant goes by the same name. Crow dipper is another name. One website refers to it as green dragon, another calls it voodoo lily. Botanically speaking, it’s closely related to our native jack-in-the-pulpit.

Pinellia is a smallish plant only eight to twelve inches tall and can grow in a variety of environments as long as the soil is well-drained. In our garden it is growing as a weed in full sun. Actually, it is growing in the shade of taller sun-loving plants, it is flourishing under the peonies that we brought in from another garden.

It was present as a persistent weed in that original garden too. We thought we were very careful to remove any trace of the Pinellia when we dug the peonies – apparently that was not the case. Now six years later we are still fighting it.

Unlike the other weeds we’ve accidentally brought in, these we have been able to keep confined to one relatively small spot in our garden.

Pinellia is very well adapted for reproducing itself and is quite competitive growing among other plants. It produces both tubers and numerous seeds, making it doubly sure it will reproduce one way or another.

You can see the small tuber growing on the root. Each piece of plant will have at least one.

You can see the small tuber growing on the root. Each piece of plant will have at least one.

This past week we re-dug the peonies along with the infested soil they were growing in. The peonies we saved and replanted; the soil we bagged up and set it out for disposal in the landfill. Home composting will not destroy all of the seeds or tubers.

In some parts of the country people are planting it as an ornamental, it really is an unusual looking plant. Either it behaves itself in certain climates or it hasn’t become a big enough problem in those areas. People on gardening chat sites marvel how well it spreads without any effort on their part. In some states it is officially classified as a noxious weed.

Even though you can find reputable plant sources online extolling its virtues, I highly recommend against planting it. People say, “I’m a conscientious gardener and would never let it get out of control”. That may be the case but what happens if you move and sell your house, would the new owners be as vigilant?

There is a purple cultivar of Pinellia tripartita that is supposed to be non-invasive, I would never take a chance on that one either.

Bob

 

 

May 16, 2019

Ornamental pear trees may become invasive in the future

Ornamental Bradford pear trees are in full flower right now. They must be everyone’s favorite tree, or you would think so because everywhere there’s a housing development there’s at least one Bradford pear tree planted in front of every house. Even municipalities and businesses are planting them.

They do have a certain charm and they’re quite eye-catching when they’re in full bloom. But there’s so many of them now that they’re beginning to just become part of the background visual-noise instead of  being an accent in the landscape.

Landscapers plant Bradfords because of their flowers, shape and moderate size, and even though they are an introduced species, they are believed to be non-invasive by many. That has been the case in Michigan until recently. There’s evidence that these trees have become tired of being well-behaved and have decided to cut loose from their suburban lawns. This was pointed out to me a couple of years ago by a local, well-respected naturalist. To drive home her point she said all you had to do was look at the number of wild Bradford pears growing all along the highways.

Well, I drove the entire length of I -275 this week and was surprised how many out of place Bradford pears there were. They weren’t overcrowding any one area but there were plenty of single trees and small clusters of them. When you’re looking for them you begin to see them everywhere.

Even though this tree was covered with flowers, no bees were around. Bees seem t prefer other kinds of flowers if given the choice.

Even though this tree was covered with flowers, no bees were around. Bees seem t prefer other kinds of flowers if given the choice.

These more boisterous, escaped trees are claiming some area for themselves and have the potential to push out the native plants. The conventional wisdom that they are sterile and unable to reproduce may be true but something is going on. It brings to mind what Jeff Goldblum’s character Ian Malcolm said in the movie Jurassic Park, “Life uh, finds a way”.

In some other states Bradford pears are already a big enough problem that they have been place on those states invasive species list and are no longer recommended for planting.

To be fair, Bradford pears may never become a problem for us. I remember early in my career when, for a short time, some people worried smoke trees might escape and become invasive. Some trees did take root out of place here and there but the smoke tree invasion never materialized.

Maybe it’s time to think about developing a replacement for the Bradford pear if for no other reason than to add more variety to the suburban landscape.

Bob

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