Tennessee Smart Yards Native Plants

A comprehensive database of Tennessee native plants

Category Archives: Not-so-favorite Native Plants

Frost Aster — A blessing or a scourge?

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Aster take-over, just before blooming

If you don’t have Frost Aster in your garden yet, you will! It seems to be just a matter of time. It took almost 8 years for it to show up in my gardens and then it made up for lost time by becoming one of my more abundant flower species.

Frost Aster (also known as Hairy Aster, Downy Aster and White Oldfield Aster) is Aster pilosus (or if you like to keep up on the latest scientific name changes Symphyotrichum pilosum). It likes full to part sun, most any moisture level except swampy and most any soil except gravel. It grows typically about 3 to 4 feet in height, is covered with an abundance of small white flowers for an extended period in fall, and spreads aggressively by both rhizomes and self-seeding.

I first noticed it several years ago when, in fall, one whole section of my yard was suddenly covered with white flowers. I liked the effect because it was almost like a light layer of snow. Then last summer I eliminated another section of lawn. In December, I put out a lovely selection of wildflower and native grass seeds, all of which came up nicely this past spring. However when fall arrived this year, I now have nothing but a solid stand of Frost Aster, with the other species barely visible between the Frost Aster stems. Maybe some of my seed had been mislabeled by the nursery? I called to ask, and they reassured me that there was no chance of that. One of the staff suggested that I spray the whole thing with Round-Up and start over.

I really didn’t like the Round-Up solution so I started doing research, checking with any native plant specialist I could find. To my surprise, I discovered that many nurseries sell Frost Aster seed (a good sign). I also learned that Frost Aster tends to come and go in spite of the fact that it is so aggressive (another good sign). I also learned that it is a very valuable plant for bees and butterflies. As one garden reference so nicely put it—“We have lost so many flower species valuable to pollinators, we should be glad that there is Frost Aster which can help fill the gap that has been left” (another good sign). So I decided to leave everything as is and see what happens. I will either be left with a solid, perpetual stand of nothing but Frost Aster or, over time, it will gradually integrate with the other species. It is certainly a chance to learn more about how Nature operates.

This experience has been an important reminder that I am no longer in charge of my yard and its plantings—Nature is now in charge. When you first start planning to install a native plant meadow, picking out plant species and doing the layouts, you are in control. But gradually Nature takes over, and now I have slowly come to realize that I am no longer in control. Funny that it has come as a bit of a surprise, but when I look back, it makes sense. Plants now come and go at their own discretion based on weather, lighting and soil. The only role I have left is to patrol for the unwanted visitors – pokeweed, dandelions, poison ivy, etc. — and remove individual plants where I find them, and, of course, more importantly, to learn from Nature

Native Plants I Wish I Hadn’t Planted!

I always like to diversify my native plants as much as possible, and even though I try to research each species ahead of time, some of them always come back to bite me.  Here is my list of regrets.  If anyone has had a different experience with these plants or has found a way to deal with them, please post a response.   Also to help out the rest of us, please consider posting your own list.

Here is my list from worst to “least worst”:

Virginia Wild Rye (Elymus virginicus)

1.   Virginia Wild Rye (Elymus virginicus).  I can’t find a single good thing to say about this plant except that it is a cheap and very easy-to-grow grass.  Since it is a cool season grass, it dries to a crispy brown in Tennessee’s summer heat and looks like a farmer’s field ready for harvest.  It can’t stand up by itself in a storm and takes everything around it down with it when it goes.   It is listed as “short-lived” but that is inaccurate.  I have been pulling and dead-heading it for five years.

2.   Big Bluestem (Andropogon gerardii).  Generally, this is considered a very desirable meadow grass.   Tall at 6-7’, it is sturdy and generally stands straight even after a storm.  But it RE-SEEDS to the point of taking over and driving out everything else in just about 3 years.  I complained to my seed source, but I don’t think they believed me, saying only that they had never heard of such a thing.  I did buy my seeds from a northern state, so maybe I got a northern “ecotype” of the plant that just goes nuts in Tennessee’s warm climate.  What are other people’s experiences with this plant and where did you get your seed?

3.   Wild Strawberry (Fragaria virginiana).  Although it is a charming, attractive groundcover, its ability to spread puts Bermuda  grass to shame, especially if planted in sun.  It works fairly well in dry shade, but it is almost like something from outer space if put in full sun with plenty of water.  It is often on rain garden plant lists, and I made the mistake of using it in my rain garden.  In less than 3 months, a total of 6 plants had buried every other plant in the garden, and when I pulled it all out, I had rooted plants about every inch to half inch.

Wild Petunia (Ruellia humilis)

4.   Wild Petunia (Ruellia humilis).  This plant is a darling, small purple petunia that makes a great groundcover.  I read that it shoots its seed up to 10 feet through the air, which at the time sounded rather charming.  In reality, it is a huge headache if you have any areas within 10-15 feet where you don’t want it or if it is planted among less aggressive plants.   Since it blooms the first year from seed, those plants will then send their seed out another 10 feet..…kind of an exponential explosion.  Even though it is a small plant, you cannot hand pull it by the roots .  I am no longer sure that I want it, but it is too late.  Once planted, it is so invasive that it is here to stay.

Sweet Black-Eyed Susan (Rudbeckia subtomentosa)

5.  Sweet Black-Eyed Susan (Rudbeckia subtomentosa).   This plant is both pretty and a huge headache.   It is a great rain garden plant with bright yellow flowers.  However, it is a giant plant at 5-6’ that sprawls in all directions by mid-summer, burying everything around it.  It re-seeds with abandon, popping up everywhere in the yard.  If you don’t have too many, the only solution is to cut it back to at least half its height in early June, which turns it into a somewhat manageable bush by the time it blooms in late July.