There are so many wonderful plants to add to your garden, but here are six plants that you may want to avoid. Some of the nicest looking plants can be invasive or poisonous and definitely don’t deserve a place in your garden.

If a neighbor or friend offers you a plant, make sure that they aren’t offering it because it is something that has spread wildly throughout their garden. Often people mistake something that is actually invasive for something that is just doing well in their garden and will accidentally spread this plant to friends. In my post about finding free plants for your garden, I discuss taking plants from friends, but make sure you are very careful!

You want to avoid these six plants in your garden, and check out my favorite perennials instead!

Mint

Fresh mint is a wonderful herb! It can be used fresh in delicious summer drinks, like this non-alcoholic mojito recipe or dried to use for tea. Never, ever, plant mint in your garden bed or you will be one of many gardeners finding out the hard way that mint is a voracious spreader. Mint will quickly send out runners to fill any garden space.

This doesn’t mean you can’t grow mint, it just means that you should always plant it in a pot and keep it up on your deck or patio so it doesn’t spread into your garden. There are so many different mind varieties to enjoy, plant a few in a large planter and pluck leaves to eat fresh or throw into a soda. In my early garden days I planted two mint plants in a raised garden bed and quickly found out how poor of a decision I had made. In the end, I had to take all of the soil out of that bed and start over.

Tansy

Tansy is a herbaceous perennial that is sometimes used in traditional medicine. This tall, full, plant with bright yellow button flowers can look appealing, but it should never be planted in your flower gardens. Tansy is considered a noxious weed in most parts of North America and it is very invasive. It will spread with runners and seeds that can live up to 25 years!

In addition to being an invasive plant to avoid, it is also toxic to humans and animals. Don’t be fooled by its pretty yellow flowers and herb scent, this is definitely one that you do not want in your garden. It has very strong stalks and roots and it quite difficult to remove once it gets established. You will often see this tall yellow plant growing in ditches on country roads. Instead of tansy, you might consider planting a variety of yarrow which isn’t quite so invasive.

Bachelors Buttons

These tall beautiful blue flowers are easily sourced from your local garden center, but buyer beware! As someone who planted bachelors buttons in my sunny front garden, I am still pulling plants out four years after I planted the mother plant. If you remember to cut the seed heads before they go to see, this plant will produce beautiful blue flowers that bees absolutely adore. If you forget to cut the seed heads, you will find that these plants spread rapidly throughout your garden.

Unlike mint, these plants are very easy to pull out of the garden, so if you don’t mind having to pull out seedlings all season long, then you may tolerate this plant in order to have its blue flowers in your garden. I prefer my blue mounding perennial geranium, it gives me the same color without any of the fight!

Ox Eye Daisy

Ox eye daisy is another invasive plant that often gets handed out during plant swaps or from a well meaning neighbor. This is not your flower store daisy! This daisy will spread rapidly and is considered an invasive species in many jurisdictions. You will see these daisies spreading in farm fields and ditches, and though they may look pretty, they do not belong in your perennial flower garden.

If you are looking for something that looks similar but doesn’t spread, try planting shasta daisy.

Lily of the Valley

Lily of the valley is often said to be a wonderful plant to fill in a shady area of your garden. It certainly will fill that area in, and then some. You may want to try this plant, but use caution as it can spread very rapidly.

The fragrance of these shade loving perennials is very tempting, but know that their flowering time is short lived. Once the flowers are spent, you are left with lots of green leaves and a plant that will fill in just about any area. If you choose to plant these, keep in mind that they are very hard to contain and will often spread through fences and into your neighbors backyard. These are not a welcome visitor and are a plant you want to avoid.

Creeping Bellflower

The pretty blue flowers on this creeping bellflower tempt some people to use them as a ground cover. Of all of the plants I have listed this is the one I would avoid at all costs. It will spread, and spread, and spread some more until your neighbors are calling and wondering what you have done.

This is another plant that new gardeners often accidentally share with friends because they think its blue flowers are pretty and it grows so well. It is also often confused with other forms of bellflowers and so people will share it thinking it is a beautiful perennial flower. The roots of this plant will spread powerfully, and one single rhizome can end up spreading up to 15,000 seeds. Keep this out of your garden at all costs!

There are so many safe and beautiful perennials that can be used to fill your garden space. Think carefully before accepting a plant from anyone and avoid these six plants in your garden.

What other plants have you learned to avoid? Let me know in the comments below!