Do Agapanthus Multiply? All About How Lily of the Nile Spread

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do agapanthus multiply

Maybe you just planted some new Lily of the Nile plants and you’re wondering if they’ll fill in your garden with new plants. So, do Agapanthus multiply?

Yes! Agapanthus multiply by sending out underground stems called Rhizomes. These stems emerge from the ground as new plants that are identical to the original plant. Despite being attached to the original plant, these plants can grow independently if removed. This is only possible if they retain some roots when moved, though.

How Does Agapanthus Spread?

Now that you know the answer to the question: “Do Agapanthus multiply?” I’m going to dive a bit deeper into the topic.

These plants spread by both underground Rhizomes and seeds. But these two methods are not equal.

Rhizomes

Spreading by Rhizome is the way that you want your Agapanthus to grow. This is how your plant goes from one bloom stalk sprouting from a few leaves to more than a dozen bloom stalks sprouting from scores of leaves.

Rhizome stems travel underground and emerge from root clumps. These clumps reach a mature width and stop spreading.

Rhizomes ARE identical clones of the plant that they come from, so you can divide them and replant them elsewhere or give some away to friends or family.

On the negative side, Rhizomes are the reason that you’ll have to divide your plant clumps periodically. Agapanthus have thick, aggressive roots. These roots will intertwine over, under, beside, in-between, and generally all-around each other. Over time, this will make it almost impossible for them to absorb water and nutrients.

I cover when you should divide Agapanthus further down in this blog post.

Seeds

Most people are wondering about underground spreading when they ask “Do Agapanthus multiply?” But, seeds are a less desirable way for your Lily of the Nile plants to spread. And chances are good that your plants will try to reseed every year.

In nature, seeds allow Agapanthus to travel farther and begin new clumps, which is something that Rhizomes don’t do.

In the modern garden, you might think that you want your Agapanthus plants to spread far and wide. But you should know, the plants that emerge from seeds will NOT be identical to the parent plant. There’s a good chance that they won’t have the traits that you like from the parent too. They might be less compact, have different color flowers, or just have a “wilder” appearance overall.

These babies can be interesting and unique, though. If you have a lot of time on your hands, or just want to experiment, you can grow some of these seedlings to see what you get. I recommend growing them in their own grower pots, though, rather than growing them in the ground. They tend to be delicate over their first couple of years. Also, keep in mind that they may take 2-3 years to actually flower.

Reseeding is also the reason that Agapanthus are invasive in some areas. So if they are invasive in your area, you want to watch out for that.

How To Stop Them from Reseeding

There is a very simple and quick way to keep Lily of the Nile from reseeding in your garden.

  1. Wait until your plant’s blooms are spent (shriveled up and/or fallen off).
  2. Snip off the entire stalk. I recommend snipping the stalk off below the plant’s foliage. This way you won’t have bare sticks poking up from your plant.

Make sure that you throw these stalks away in the trash instead of burning them or leaving them around for a child or dog to play with. Agapanthus plants are toxic, so you don’t want to risk exposing anyone to this toxin. If your dog or a person ingests any part of the plant, consult a physician or vet (respectively) quickly.

How Far Apart Should I Plant Agapanthus?

There’s a trick to spacing Agapanthus properly. You want them to grow into each other to avoid having awkward gaps between plants. But if you plant them too close, you’ll end up dividing them much sooner.

I recommend planting them 60-90% of their mature width apart. Therefore, if their mature width is 24 inches wide, plant them (from center of the plant to center of the plant) somewhere between 15-21 inches apart. This way, they’ll grow into each other, but still have space to grow uninhibited for a while.

If they are different species with different mature widths, reference the one with the larger mature width. So if one gets 30 inches wide and the other grows to 18 inches wide, plant them 70-90% of 30 inches apart.

How Quickly Do Agapanthus Grow?

It’s difficult to say how fast Agapanthus grow as a species. Some grow faster and some grow slower than others. On average, expect them to reach their mature size in about 3-5 years.

Larger varieties will often grow faster, but they have more ground to cover and then they’ll still need more time to fill in. Dwarf selections have much less ground to cover, but they’re pretty much always slower-growing.

Keep in mind that their growth speeds up over time. If you have one plant with one stem your first year, it may produce 3 new stems the next year. Then those 3 can produce their own stems the next year, so you may end up with 9 stems. Then you might have close to 30 the year after that.

When Should You Divide Them?

This will depend on how they’re planted.

  • If they’re planted in the ground, expect to divide them roughly every 4-5 years.
  • If they’re planted in a pot that’s smaller than their mature width, expect to divide them about every 2-3 years.
  • If they’re planted in a pot that’s wider than their mature width, it’ll be similar to if they were planted in the ground, so every 4-5 years.

There are a couple of surefire ways to know that your Agapanthus need to be divided.

  • Did they grow like champs for the last few years, blooming beautifully with rich healthy leaves, but this year they only sent up one or two lackluster blooms (or maybe even none)? Unless you drastically changed their growing conditions, chances are that they need to be divided. The roots have probably become so compacted that water and nutrients are unable to be absorbed by the plant. So its blooming capabilities are severely hindered. I go over other reasons why your Lily of the Nile plants may not be blooming in my post “When Do Agapanthus Flower?” so check that out if you still have questions.
  • Does the center of the plant appear to be dead/dying? The center of a perennial clump is always the first part to die when the roots become compacted. The outer plants can access nutrients and water from the outside, the inside plants cannot. So you’ll end up with a ring of living plants around a circle that is either dead or struggling.

I cover how to divide Agapanthus in my post on Lily of the Nile care.

Concluding Thoughts: Do Agapanthus Multiply?

Now I hope I’ve sufficiently covered the question “Do Agapanthus multiply?” along with several related Frequently Asked Questions.

Still unsure of where you should plant some new Lily of the Nile plants? Read my post “Where to Plant Agapanthus” for inspiration.

Thanks for reading! If I answered your questions today, please consider sharing this post using one of the social media buttons. It really helps me out. Happy gardening!

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