Are Agapanthus Roots Invasive? If So, Why?

Drought-hardy plants are a blessing in disguise if you live in sunny areas that see limited water and soaring temperatures. The Agapanthus (Lily of the Nile) is one such plant that adapts to all of these conditions.

Yes, the Agapanthus roots are invasive as they spread to the full area that is available to them.

A seemingly dormant Agapanthus plant can shoot after a long time once it is watered because of the invasiveness of its roots.

Additionally, its roots are toxic and hard to dig up, especially if the plant is very old and has a deeply established root system. 

How Invasive are Agapanthus Roots?

When people say that agapanthus plants are invasive they are basing their opinion on the notorious nature of the roots and not actually the foliage! 

Agapanthus are very invasive and will grow to occupy all the space given to them and more. If left unattended, an agapanthus plant will quickly grow and will easily choke out other plants and invade their space!

These plants obviously exhibit something that other non-invasive plant species don’t. This could have something to do with the fact that they have bulbs and rhizomes.

Bulbs are known to help plants survive the elements and harsh conditions while rhizomes assist in rapid shooting and growth.

Also, the agapanthus species is from Southern Africa, an area prone to dry and hot climates.

So, in the USA the agapanthus is considered an exotic plant, not a local indigenous one. Perhaps their spreading across the globe has made them evolve to survive better.  

Before you know it, you will be asking the question; how to get rid of Lily of the Nile (Agapanthus) 

Why Are Agapanthus Roots Invasive? 

After hearing about invasive agapanthus roots, your next question may be what makes agapanthus roots invasive? 

Well, there are quite a few characteristics of agapanthus roots that contribute to the general hardness of this plant. Here are a few ways agapanthus roots are invasive and make the plant hardy:

  • Agapanthus plants have root bulbs which can help the plant remain viable for a long time. Thus, it can shoot when watered after a long dry spell, as they are alive but dormant.
  • The rhizomes and root matter of these plants are highly regenerative meaning with the right conditions they can grow into new plants. 
  • When given the right conditions, agapanthus could grow rapidly, making them and their roots even more invasive. Several rhizomes arise from the bulb simultaneously.
  • All foliage and root matter of agapanthus contain a toxin that induces allergy symptoms. Perhaps this is why some people leave them alone and let them spread. Eventually, this is the reason why they become unmanageable and roots may be left behind if an attempt to excavate them is made.  

If all is well and they grow to their full potential, this is exactly how Agapanthus becomes a weed.  

How Toxic are Agapanthus Roots?

There’s a reason why agapanthus roots are not the most fun to dig up and get rid of. Apart from being difficult to remove, these roots are not spared from the toxin that is present throughout the plant. 

Saponins are a toxin that is synthesized in and circulated throughout the entire plant. It may also be highly concentrated in the bulbs and roots of the plants.

Saponins can cause gastrointestinal problems like diarrhea, vomiting, bloating, and abdominal pain when ingested by humans or animals. Also, when the sap containing the toxin comes in contact with skin, it can cause swelling, itching, and irritation. 

NOTE- In severe cases, a doctor or vet will have to treat you or your pet if you’ve been accidentally affected by the toxin. 

Find out exactly; how poisonous are agapanthus? 

Do Agapanthus Have Deep Roots?

Agapanthus plants don’t have deep roots when they are fairly young. However, they may develop deep roots if they are not separated and left alone for many years in which case they will become very established.   

They develop large clumps of bulbs and rhizomes and can easily overwhelm the pot they are growing in. To uproot the plant, you might find yourself breaking the pot to get it out!

Apart from the roots growing quite deep, you will also find agapanthus have very thick rhizomes. Due to these characteristics, an agapanthus plant should be repotted and separated to avoid it becoming bushy and very invasive. 

Why Do Agapanthus Attract Bees?

Do Agapanthus Spread Fast?

Yes, they do! In fact, agapanthus is on the higher end of the spreading spectrum. They can spread via both rhizomes and seeds! 

Spreading most commonly occurs through the rhizomes which slowly expand the mother plant. Also, people divide up the clumps sharing them with neighbors and friends, hence you might find the plant distributed through quite a large area. 

Gardeners thinning out their agapanthus clump, or just getting rid of the plant might dump it at their local landfill or open space. The agapanthus might just take root there, depending on conditions.

They do not die easily and will shoot up upon watering- probably rainfall. 

Should You Plant Agapanthus in Pots to Prevent Spreading?

Ground or pots, which one favors agapanthus spreading?

Honestly, it depends on the climate and conditions in your area and garden. 

Agapanthus plants are very vulnerable to cold and especially frost. You must bring them indoors if you want them to survive! Growing agapanthus in a pot lets you bring it indoors and out again.

A pot can restrict agapanthus plants but keeps them alive.

Having the Agapanthus in a pot keeps it from spreading uncontrollably elsewhere. However, do note that these plants can break out of the container. 

Growing them outdoors will bring your garden to life with the long, lush green leaves and subtle flowers. They are great for making borders or filling a large space if you have any.

Unfortunately, agapanthus is most invasive outdoors, they spread very fast!

If you have limited space in your garden, want a hardy plant, and don’t have extreme winters, you can plant your agapanthus outdoors. 

How to Stop Agapanthus From Spreading? 

Suppose you are growing agapanthus plants because you like the way they look. But, at the same time, you don’t want them to spread. You’ll want to know if you can stop agapanthus from spreading and how to do it?

There are two ways the agapanthus has of spreading itself, through seeds or through rhizomes, which are like thickened roots. The wind does the job of seed dispersal, blowing away the seeds, far from the mother plant, to grow elsewhere. 

Here’s how to stop agapanthus from spreading:

  • It is best if you cut off the flower stalk post-flowering so that the seeds will not develop or have a chance to spread.
  • Constantly thin out your agapanthus plant by digging up roots and rhizomes throughout the ground.
  • Be careful where you dispose of your agapanthus plant matter as a complete plant can grow from the bulbs or rhizomes. 
  • Use effective methods to kill the agapanthus plant matter before disposal.  

But, we should remind you that there are still high chances of it getting out of hand in a short time. Keep an eye on your agapanthus to know when that is.  


Agapanthus roots are very invasive which gives the plant a bad reputation for spreading fast and being a bit troublesome to remove. They could easily take up too much space and resources.  

Agapanthus plants have roots that contain bulbs and rhizomes (underground shoots) that help them become so invasive. Without your watchful eye, agapanthus plants will spread to take over the whole garden if possible. 

To stop agapanthus from spreading, you can:

  • Remove flower heads before seeds drop/disperse.
  • Thin out your agapanthus often to avoid it from becoming too big and invasive.
  • Use the chemical glyphosate to kill the agapanthus plant with limited physical labor. 
  • You could alternatively dig it up, solarize it, or smother it. 

Don’t know where to plant your agapanthus? It might help to know do agapanthus like full sun or shade?


Does Agapanthus come back year after year?

It is possible for agapanthus to shoot year after year as they have hardy roots and bulbs. If you live where winters are not frosty, your agapanthus won’t need any protection and will thrive throughout the year. But in colder areas, agapanthus may not come back every year if they have undergone extensive damage. 

Will Agapanthus roots regrow? 

Yes, the roots of agapanthus plants will eventually regrow when conditions favor it. This could mean warmer weather and water could make this plant’s roots sprout again. So if you have just dug out and thrown away agapanthus bulbs, they are very likely to grow again!

Is Agapanthus poisonous to dogs? 

Yes, agapanthus plants are poisonous to dogs and cats. If these animals ingest the plant matter of agapanthus, they will have gastrointestinal upset. If the poison comes in contact with their body, they could suffer swelling and itchiness. So, it’s best to keep your pets away from agapanthus plants.