9 Plants You Don't Want in Your Garden

Do you have some plants in your garden you wished you hadn't planted? You are not alone. Most  gardeners I know of are plagued by a plant that took over and are now wondering how to get rid of them PERMANENTLY. In my case, it is Periwinkle and Crocosmia as we speak.

If you are like many weekend gardeners you are always on the lookout for free plants that you happily plant in your garden regardless of what the consequences might be. Read on what plants not to put into your garden even if you are looking to fill a space and even if they are free. 

These are plants that I or my friends have had first-hand experience with. Some are very aggressive spreaders, some are invasive and some just take up a lot of space without adding beauty to the garden.

However, a little disclaimer is in order. What is considered aggressive, invasive, or a vigorous spreader in zone 4b for instance may not necessarily be so in your gardening zone. 

The terms aggressive and invasive are somewhat intertwined. The Department of Natural Resources - ( DNR) websites for your State may have their own definition of what invasive plants and aggressive plants mean. Per the Oxford Dictionary invasive means: “tending to spread prolifically and undesirably or harmfully” and aggressive means: "a plant that spreads faster than preferred, or into an area of your garden where it’s not wanted" (as paraphrased from the Chicago Botanic Garden website). 

Plants grow differently in different soils and different climates at different rates. This post is written based on my own observations and experiences.

9 Plants Not to Have In Your Garden

Let me start with my 3 most "hated"...

Periwinkle aka Vinca minor (common names lesser periwinkle or dwarf periwinkle) 

is a species of flowering plant in the dogbane family. This is a groundcover that spreads rapidly and is VERY invasive and hard to get rid of.  This plant has literally choked a couple of my bushes to death. In addition, during the hot summer month, you will end up looking at burned leaves, making this plant quite unattractive.

Crocosmia  (montbretia)

This one seemed like a good idea because this plant is quite pretty. Crocosmia blooms are produced on slender stems of 2 feet (0.5 m.) or more in length. The flowers appear in May or June and the plant will keep producing all summer.  Crocosmia plants grow from corms, which are closely related to bulbs. In addition to seed pods (which are quite nice in flower arrangements), they will also produce runners underground which form new corms, and before you know it, they have taken over a large space in your yard. Do not plant unless you can let it roam freely.

Morning Glory Vine -  ( Ipomoea purpurea) 

I saw this description at the Hudson Valley Seed Company and since it mirrors my sentiments exactly, I am repeating it here: "The morning glory is like a good marriage. Its vines are strong and grow steadily but require a framework of support to reach their maximum potential. Its profuse blooms require frequent, immediate appreciation, as they last but a single morning before fading. And at its core is a seed that can adapt to any circumstance, self-sowing readily and thriving even in difficult soils. In fact, like the best marriages, morning glories flower most when faced with distress: drought and low-nutrient soils lead to blooms in profusion."  My vine has made its way up high into the adjacent Birch and Pine trees and invaded the entire upslope and even the neighbor's yard. So, unless you are a big fan of seeing blue or purple blossoms everywhere, I suggest you pass on this one.

Other Plants to Think Twice Before Planting

Snow-on-the-Mountain (aegopodium podagraria) – a/k/a Bishop’s Weed or Gout Weed 

I never thought that I would say this, but I ended up regretting planting this one. When someone gifted me this one I was excited about getting this pretty ground cover with its variegated leaves. Ground cover indeed! In no time did it cover everything in its path.  Snow-on-the-Mountain is so invasive and it spreads by underground runners. It took me years to completely eradicating it from my shade garden. Do not let this beauty fool you.

Royal Standard Hosta 

You probably did not expect this one on my list. In my opinion, royal standard hostas (the very common plain green hostas) just aren’t all that pretty and they are huge slug attractors.  And, they are definitely the most prolific hosta out there. 

Lambs Ear (stachys byzantina) 

The foliage on Lamb’s Ear is pretty and it adds a cool texture element to a flower bed. But once it starts flowering, it gets ratty looking. In addition, the flowers are not attractive, and it just takes up too much real estate in the flower garden. On the positive side, Lambs Ear is a known bee magnet, but there are tons of other prettier flowers that are bee magnets too.

Lily-of-the-Valley (Convallaria majalis) 

Don't fall for this beauty, despite their lovely flowers and sweet smell. Great choice if you love to pick bouquets for your home but, they bloom for such a short time and are naughty spreaders. No matter what, they don't stay where you put them.  Don’t be swayed by this picture or their fragrance – stay strong!

Obedient Plant 

I was quite smitten when I first saw this plant.  It's so pretty. But it did not take long for me to fall out of love because like the Crocosmia it spreads via underground rhizomes making it anything but obedient.  It’s called “obedient” because you can actually bend the stems to face the direction you want them to face. I know of no other plant you can do this with.  But in spite of this, pass on this one.

Common Orange Ditch Lilies (hemerocallis vulva) 

I think these are my least favorite of the lilies because they are prolific spreaders. Plus, ditch lilies take up a lot of space and there are so many other beautiful, cultivar and hybrid daylilies that you could use instead. Plus, you constantly have to remove the dead leaves and flower pods just to keep them decent looking. I would rate them as invasive because they crowed out other plants. 

There are many other perennials that some would call invasive or aggressive, including: bee balm, lamium, ajuga, cherry bell campanula (and a few other varieties) and agastache. I did not include them in my list because they are not a problem to weed them out and I like them well enough, so for me,  they are worth the effort. 

So how on earth is a novice gardener, or even a seasoned gardener like me, supposed to avoid ending up with perennials that will take over your garden. My best advice is just to read up and ask questions. Now, if I see a plant that I don’t have and I’m curious about, I will ask the seller or giver these questions:

• Is this plant a vigorous spreader or aggressive? If so, is it easy to weed out?
• Does this plant spread by underground runners?
• Is this plant invasive?

If there isn’t anyone available to answer my questions, I will do a Google search on the plant name and quickly read up on it.

I hope this blog post was useful and informative.