Tuesday, February 25, 2014

A Dirty Dozen - Plants to keep out of your garden!



Keeping invasives out - to make room for these beauties!
I'm making my spring garden to-do list and I notice that many of the tasks involve getting rid of plants rather than planting them! These are my "dirty dozen" of plants I wish had never rooted on my land. Managing these highly aggressive / invasive species is a major chore.  These plants expand via fast-growing roots or rhizomes or expel dozens of seeds annually. So over time you may get much more than you planned!  Many of these are plants I purchased at garden centers or picked up free online through Craigslist or similar sources. Getting plants free should have been my clue that these plants go CRAZY!  Others I inherited with the garden when I first moved in- nearly 12 years ago, this challenge started with Bishops Weed and honey suckle. I pulled them out, cut them down and still they return year after year. I spray them and abuse them. They can be very B-A-D. I'm still at it - and there is not much left. Man some of those roots are tenacious! Beauty is in the eye of the beholder. Clearly the former owner of my house LOVED her buckthorn and honeysuckle greatly. Fellow gardeners in my neighborhood love some of these and readily take up the debate as to why I'm pulling them out. My response is always that they are taking space, resources and time from the plants that I really want to flourish in my garden.
So, here's my "Dirty Dozen" of plants I would like to bite the dust and never return. Your experience may vary - but I encourage you to think twice about putting any of these in your garden.

1) Bishop's weed: This plant was fairly well contained along the walkway and bordered on all sides by the house and cement walkway. Somehow it leapt over into the garden and there if thrived.  I tore it out and sprayed dilute vinegar whenever it reappeared. Mind you - I pulled a full 4 inches of soil out to try and get all the roots. So many years later - I still see spots of it!  It was a very pretty ground cover, however it just wouldn't stay in (its) bed! There are "non-spreading varieties" but I'm sceptical.
2) Sweet woodruff:  This plant seduced me with it's sweet-smelling hwite flowers and pretty leaf structure. I picked up several clumps from a fellow master gardener who did warn me that it can be aggressive. Well I needed a low-growing ground cover so Galium odoratum got the nod. But it spreads by root to create a thick mat and it doesn't respect boundaries of nearby plants. How rude!  I am keeping this in the garden but each spring I pull out everything one foot from the edge of where I want it to be in summertime. Plus I give lots away (with warning naturally!)
Evening Primrose - Aggressive / Invasive Plant
3) Sundrops, evening primrose, suncups I saw this flower at a neighbors house, growing up against her deck and in part shade. It was so brilliant and happy, I asked to take some home. Less than 2 years later she and I would both complain that we ever put it into the garden. I had taken over!  The plant, Oenothera tetragona, will fill a spot very quickly. It is much easier to pull out than other plants listed here.  This is as long as the roots are distinct - that I caught the srpeading early enough to keep out of other plants.  It is less drought and shade tolerant and will spread less in these areas.

4) Bee balm: This is another plant that I actively sought out for my garden. I loved the vibrant red flowers and the wildlife they brought. I got it for free from another gardener who was riping it out of her garden. Bee balm (Monarda didyma) is a major-league spreader.! This native plant spreads by roots and it can quickly conquer the garden. I rip out skads of it in the springtime to keep it in check. I also do not allow it to go to seed.
5) Baby's Breadth: Yes, I'm talking about that flower that is in all the flower arrangements. I saw the seeds and though how lovely it would be to have a clump of this to use with cut flowers.  The bushy plants can be 2-4’ tall. The blue-green stems are highly branched and they spent more time flopped over on the ground than standing up straight. They are very difficult to get rid of because small parts of the large taproot can form new shoots even after most of the root has been destroyed.  I cut it down and applied herbicide to the stump.
6) Mint: I remember my mother having mint in the garden and never being a problem with it getting out of control. I however, was not that lucky. No matter what variety I use - it always gets away from me.  I have taken to only having it grow in containers. If the mint looks like it might flower, I decimate it and dry the leaves. To get rid of it from the garden soil - I pulled the roots and then used a dilute vinegar solution. When that didn't work, I poured boiling water slowly onto the dirt/roots (it's in my vegetable garden so I didn't want to use too much herbicide.)

7Thyme: This wasn't so bad of a plant as the others listed above, however it was always creeping over into the lawn past the edge of the herb garden. It was much more successful than the other herbs. I guess maybe I didn't use it enough. I've moved it to a small pot near the door. Maybe that will work better. 

8) Queen Anne's Lace: This plant (Daucus carota) is native to Europe. I't pervasive across the street and thus in my yard. It invades disturbed dry prairies, abandoned fields, waste places, and road sides. I hand pull it but with a tap root I'm not always as successful as I'd like. I also make sure to cut it down before it flowers because the barbed small seeds stay viable in the soil for 1- 2 years. I'm sure that deer are bringing it into my yard every year.


9) Orange Daylily:   Thanks to the victorians for introducing the Common or orange daylily(Hemerocallis fulva)  into the United States in the late 19th century as an ornamental garden plant. It is a popular plant favored  for its flowers, hardiness and ability to spread. There are 40,000 cultivars, many of which likely are or have the potential to become invasive. Did you know that Daylily buds and flowers are edible and have a sweet-spicy or peppery flavor. I've shoked guests with this flower on salads!  I picked up most of my daylilies from other gardeners. Once established, daylily multiplies and spreads to form dense patches that displace other plants in the garden. The thick tubers make it a challenge to control. I dig them out and give away every year.


10) Yellow Lamium:  Extaordinary creeping variegated yellow lamium (Lamium galeobdolon 'Variegatum') I picked up from a fellow gardener. It took a few years to take in my garden - now I also pull up big chunks of it to give away each year.


11) Golden Rod:   This plant is almost always around in the area of the woodland I'm trying to restore. I've never like it at all - but understand others do like this native. This invasive native can often be a problem in prairie restoration. It is clonal, forming fairly large patches, and grows so densely that other "good" species can't get a foothold. I spray the plant leaves with a dilute herbcide. I make sure to not let any remaining go to seed and they are so numerous!


Japanese Knotweed - Invasive
12) Japanese Knotweed:  I have a few varieties growing in my garden. One, I love the unique leaves.  See this picture - how unusal is that? The other, "ugly" one, Yuck, I can't stand. It wasn't until last year that I discovered it on the invasive species lists of many states.  Cutting the knotweed only removes the above ground portion and only serves to stimulate the below ground rhizome.  I've tried pulling my "ugly" knotweed for years.  This year, cut and treat with herbicide should do the trick.

13)  (Bush) Honeysuckle   - In the woodland resotration there is a monoculture of the honeysuckle in the understory. In my yard the former owner had over over a dozen bushes planted.  When we first moved in I argued to keep the shrubs in place - ok not I can see that other than the brief flowering and aroma in spring, these plants offer noting to my landscape. Plus they take over everything. I cut them down and paint the stumps with herbicde. I'm considering putting in some alternatives in the woodland such as eastern redbud; dogwood spp.; viburnum spp.; witch-hazel and hazelnut.


OK - that's my (Baker's) Dirty Dozen! What is on your list of plants to keep out of the garden? I'd love to learn from your experience.

Enjoying the humorous lyrics of Jelly Roll Morton singing The Dirty Dozen!


Happy garden planning;


Teresa Marie