Biggest mistake plantings you have made
From: Whitney Cranshaw wcransha@ceres.agsci.colostate.edu
I have been doing my spring preparations for garden
plantings. As
annually occurs, much of what I am doing now has involved culling and
cutting some of the plants that I earlier grew and that keep coming back
at volumes that are >excessive<. In other words, they are weeds to a
great extent.
I would like to ask members of PestTalk for observations on plant
species that they have had experience with that have become pernicious
weeds and that they regret having planted in the first place - or would
caution others about. My big three have been:
Jerusalem artichoke. Whew, this was a major mistake. After the
original planting it took 5 years of sustained effort to eradicate them
- and I don't really like to eat them all that much!
Horseradish. I like horseradish - but I don't like it popping up
everywhere and it is almost impossible to eradicate and confine. (This
problem was made worse when I rototilled my garden years ago and
scattered root fragments across it.) Whenever I provide someone
roots
for planting I always give the strong caveat that it be planted in a
site that is isolated.
Larkspur. I have a generic blue variety that has some nice features -
the butterflies love it among other things. However, it reseeds like
crazy. I thought I had done a good effort deheading it last summer but
it has come up like a carpet, as it does every year.
Any other suggestions of plants that can turn on you?
Whitney Cranshaw
wcransha@ceres.agsci.colostate.edu
Hey Whitney-
My biggest mistake was planting Hyssop...it's about all I
have left in the herb garden. After I had planted it, a
friend told me that I should have planted it in a clay pot
first and then planted it in my garden, pot and all. She
said that has worked very well for her. Wonder if it might
not work with some of these other 'weeds' like your
horseradish!
thia
Thia Walker
Colorado State University
1001 S. Main St.
Lamar, CO 81052
(719) 336-7734
FAX (719) 336-2985
twalker@lamar.colostate.edu
Tarragon.
Mint.
Horseradish is definitely the worst. We planted the
Jerusalem
artichokes and the horseradish about the same time - 22 years ago at the
back of the lot. The gaden has moved back to meet up with it. We
managed to get rid of the artichokes but whatever I try on the
horseradish just seems to make it mad. Any suggestions?
I also have a sedum type groundcover that has yellow flowers on it and
potentilla repens is very invasive and very difficult to get rid of.
I bougth some Thompson and Morgan seeds for Summer Pastel Achillia which
has beautiful soft pastel colored floweres but comes up everywhere.
Also stipa grass reseeds itself all over.
Mary Kirby
Lamb's Ear
from Dorothy Howard
Snow-in-summer
Yarrow
from Tony Koski
Associate Professor & Extension Turfgrass Specialist
Colorado State University
Dept. of Horticulture & Landscape Architecture
Fort Collins, CO 80523
Phone/Voice Mail: 970-491-7070
FAX: 970-491-7745
akoski@agsci.colostate.edu
csuturf@hotmail.com
I've had it with ajuga. I started out with the nice
tricolor variety which
sported back to purple. I tried desperately to yank it. Then it came back
green. Time to get out the glyphosate. After several attempts at control
using the arsenal, I dug out the entire area and sifted the soil to remove
any propagable parts that I could find. I took a look yesterday and it's
back again.
I like catmint. It's a great plant for my gravely alley (along with
California poppies, flax, et. al.), but it seeds like mad. I've spent years
eradicating this plant in places (with limited success), but I still grow
it.
I have a biennial foxglove that looks like trouble. I hate to say that I've
forgotten it's species (dalmatica?) A well-known (but unnamed) collector
gave it to me. Last year, I had at least 500,000 (LOL). It's easy to tame by
removing the flower spikes before the seed matures, but the ones that have
already dropped seem to germinate forever. I choose to keep a few of these
around.
Feverfew is a pain.
I haven't been able to get rid of the Oriental poppy in my yard in 11 years
of attempts.
I finally managed to kill my neighbor's myrtle spurge (with her permission).
There's a fun one to pull. Use disposable gloves and wash your hands
immediately.
I think Muscari is a pain, as is some species of Ornithogalum I
inadvertently imported with crocus bulbs.
Although buttercups, yarrow, and blue flax are all a pain,
my biggest weed
problems are bluegrass and aspen. I must remove a hundred aspen
volunteers
a year.
The other noxious weeds that we deliberately sow, that spread like
wildfire,
and that you can never get rid of are government employees.
I have been overrun with mint, oregano, tansy,
and--especially--grape
hyacinths. The grape hyacinths formed solid clusters of bulbs that
obliterated everything else in one large bed. I dug them out last year and
they came back again this year. A couple of weeks ago, I dug out 12"
of
soil, including all the bulbs and completely replaced it with new, amended
soil. That was my worst experience in 25 years with an invasive plant.
Carol Grever Gray
CSU Master Gardener, Boulder County
My biggest mistake planting, purchased as a diminutive
4" potted perennial
from a local nursery, was an artemesia sp. I believe it was Artemesia
absinthium,a close relative of Powis Castle Artemesia, which according to
my literature lines the walls and terraces of Powis Castle in Wales. Well,
it went to seed and lined the walls and terraces of my property much to my
dismay.
Loretta Mannix
The Horticulture Consultant
Masters Candidate in Entomology
CSU
Hey Whitney, Thanks for the tip on Jerusalem artichoke. I
was considering
planting them this year in my garden, for I love them in salads. I think I
will reconsider planting them now.
Borage is a plant that I would never plant again, because, well, I don't need
to! They are everywhere.
Garlic is a plant that I love but I can't seem to keep it contained. The
removal of flowers/seed to encourage bulb set works but as I dig up the sets
I always leave more than what I've removed.
There are a number of perennials that of course I don't like to plant because
of their aggressive nature, and unless I don't plan to plant anything else,
they are fine. Examples that most people know are sweet woodruff, periwinkle,
buttercup.
I love Red Valerian, but it re-seeds sometimes uncontrollably. Caryopteris
(Blue mist Spirea) is an aggressive re-seeder also.
Tonya
I agree on the garlic. At my last house, I had spearmint,
garlic, "winter onion"
and catnip that escaped into the lawn. The smell on mowing day was a gastronomic
nightmare.
Aegopodium (Bishop's Weed)...Good name! Tenacious stuff,
even with years of
glyphosate, kept showing up in places no where near where originally
planted. Also, agree with Blue Mist Spirea. Lychnis coronaria (Rose
Campion) also reseeds copiously - I transplanted many volunteer plants into
pots and gave them away with the warning!
One really nasty pest of the garden that I have so far not
been blessed with is
some kind of Polygonum, like a Japanese Fleece Flower on steroids. The stuff is
incredible. I've seen it 8 feet tall and suckering yards away. My elderly
neighbor just calls it "cane" or "bamboo". We spray it
spring and fall every
year with glyphosate and that seems to just barely keep it in check.
Possibly Polygonum japonicum, Japanese Knotweed or Japanese Fleeceflower. AKA Polygonum reynoutria, P cuspidatum and Fallopia japonica. By whatever name, attractive but invasive.
Greetings from the front!
When it comes to problem plants invading and persisting where
you don't want em, I'll put Kentucky bluegrass near the top. Sure
you can controll it pretty easily with glyphosate, but every spring
what creeps into strawberry beds, flowerbeds, or gardens more
than this "weed". Glyphosate isn't appropriate in some cases and
some of us don't like to use it every where.
I've got a good planting of "Pathfinder" red raspberry which is a
cultivear that was developed at the old USDA Cheyenne Hort
research station & has limited or no commercially availability. It is
a great producer in the High Plains area, but as some have already
mentioned, all red raspberries are invasive. I've been tickled to
watch the bluegrass fade out under the shade of my thicket, and
the hearty raspberry sprouts persist in invading the lawn despite
weekly mowings. I'm just tickled to have a better competetor than
turfgrass. I don't particularly like the thorny stems on the berries.
Too much of a good thing I guess.
Both of these competetors really invade my minimum tilled
vegetable garden but here it's the raspberry that dominates. Those
rhizomes creep out six or more feet a year. Each spring, I put out
notice and give away hundreds of starts for those who want this
very productive rasberry, all the time warning of it's weedy nature.
My other mistake is mock strawberry. I put it in a place that
eventually became my family's kitchen flower/herb garden.
According to Robert Cox, the variety I planted is most likely,
Duchesnea indica. It too invades the lawn. This is a relative to the
strawberry, has ornamental tasteless red fruits, but has prolific
stolon spread. I'd not plant it again in a place where we want other
perennials. I really don't mind it in the lawn. It makes a good
contrast with dutch clover. It also lacks thorny stems.
Sincerely,
D. Bruce Bosley
Morgan County Extension Director/Agronomist
P.O. Box 517 Ft. Morgan CO 80701
dbbosley@coop.ext.colostate.edu
Office (970)867-2493
Fax (970)867-8607
Home (970)842-2120
I agree wholeheartedly with the 3 you mentioned. I am
still fighting to be rid of the groundcover type buttercup. They spread by
rhizomes, are very invasive and grow in sun or shade, wet or dry. The
harebell campanula and violets are even worse. Took years to be rid of
them, using Roundup and Turflon. Now we are being overrun with California
poppies. Like larkspur they can be pulled or dug, if you have enough time
and energy. Even cosmos can reseed much too heavily.
Shirley Marken
Blue flax, dame's rocket.
In fairness, there's some woody weeds out there, too:
Aspen in heavy clay, alkaline soils on S or W exposures
Goldenraintree, still one of my favorites, but in mulched areas will provide you
with thousands of seedlings - maybe better in turf, where seedlings are much
less likely.
Schubert Chokecherry will sucker like crazy.
Common buckthorn can get annoying and birds eating fruits produce fantastic
messes.
Robert Cox
CSU Extension – Jeffco
Hi,
If I had it to do over, I would NOT plant these in my flower gardens.
Cosmos - It just comes up everywhere, gets powdery mildew and crowds out
the smaller flowers. This year I am going to treat it as a weed!
Feverfew - An older friend gave me one small plant, it comes up in the
veggie garden, the flower garden, in the flagstones. I like it but it
cannot be contained.
Oriental Poppies - They were here when we bought the house and I have
learned to just live with them.
Of course there are the flowers that seed everywhere that I love and
encourage, columbines, california poppies, blanket flower, hollyhock.
Some people would consider these to be pests.
Gail
My biggest invader is the purple variety of Yarrow--I may
never be
able to keep up with it!!
----------
I do a small garden maintenance business and I have to say
that some of my
clients have some real problems with the following:
Oregano, Grape Hyacinth, Harebell
I have worked many long hours trying to get rid of these for my clients.
Now my problem plants are:
Mints
Myrtle spurge
Yellow yarrow - the one that grows up to 4-5'
I have solved the problem with mints now by cutting the bottom out of a
gallon container (the black ones you get plants in at the nurseries)and
planting the mint in there and then planting the whole thing in the ground.
I have a circle I made with six different types of mints and it looks quite
nice. Now I can use the mints and not worry about them running all over
the
place.
The spurge is deadly. I believe it is being added to the state noxious
weed
list this year. I have been trying to get rid of it for over 15 years on
my
acreage and still have it. I understand that when it goes to seed, each
head spits out over 60,000 seeds, sorta like knapweed. Anyway please don't
plant it on your properties.
Pat in Marshall, south of Boulder
----------
I also had problems with Cosmos. They are nice for
cut flowers, but .....
Zana Jevremovic
Entomologist
Boulder Tree
At thes Jeffco Fairgrounds we got rid of the myrtle spurge
quickly with Confront, another possibility is Brush B Gon. Another good
container for mint is a chimney tile. They are 1' diameter by 4' deep.
I bury the tile 2 1/2' to 3' deep, leaving it at least 1' above ground level so
mint branches won' t lay on the ground and root. After 4 or 5 years
you must dig, thin and replant the mint or it will choke out and die. Last
year I planted a chocolate mint in a black pot, only 3" or 4" above
ground level. Yesterday I pulled out 6 or 8 branches that had grown over
the edge of the pot and had a healthy root system!
Shirley
Forgot to mention, the sap of the spurge is toxic, can
cause a skin rash which can be painful. It is particularly important not
to get it near the eyes. Use gloves when working around it.
Shirley
Yes please be careful of the spurge. It causes brown
stains on your skin
also and yes I have had the rash before. The white gooy stuff in the
middle
is what causes it I believe. After this last snow it has been real easy to
pull even the biggest ones, root and all!!
Have a question on Zimmerman pine moth. I believe I have it on some
ancient
spruce trees at my house. Does it look like popcorn on the side of the
trunk? The trees are probably 40-50' tall so I guess I will have to have a
tree company spray for me. Thanks.
Pat from Marshall, south of Boulder
