when do agapanthus flower?

So if you’ve found yourself looking out the window at your Lily of the Nile plants and wondering, “When Do Agapanthus Flower?” I have a thorough answer just for you.

Though the exact time will vary by breed, Agapanthus will start to bloom between late spring and late summer. Some varieties will still be blooming in Autumn, but none will begin blooming this late in the year. Reblooming varieties will continuously bloom through the growing season, while non-reblooming varieties will bloom for roughly 2-3 weeks.

Why Are My Agapanthus Not Flowering?

So now you know the answer to “When Do Agapanthus Flower?” But, say Spring and summer have come and gone, and you had no flowers from your Lily of the Nile plants.

What went wrong? Why are my Agapanthus not flowering?

There are several different reasons why your plants might not be flowering, such as lack of sun, lack of water, crowded roots, and frost-damage.

I’m going to cover each reason in detail.

Lack of Sun

Some varieties tolerate a little shade, but overall, they’re sun-loving plants. They need sunlight to create flowers.

Most varieties do best with 6 or more hours of direct sun daily. But they really start to suffer when they fall below 3 hours of direct sun.

Keep in mind that in conditions where they aren’t getting enough sun, they may not look bad. Their leaves may be lush and green. But this foliage is usually not as plentiful or dense in the shade and they may not bloom at all.

Lack of Water

Lily of the Nile plants don’t require a lot of supplementary water once they’re fully established in the landscape. But extreme drought and heat can affect their performance in your landscape.

Just as plants need sunlight to produce blooms, they also need water to produce flowers. If a plant becomes dehydrated, the first thing to go is the blooms.

Pay special attention to your Agapanthus from July through September. This is when they’re forming their flowers for the next year. If your area is experiencing extreme drought and/or heat, provide supplementary water for them. This is especially true for plants in containers because they dry out faster than plants in the ground.

If they’re in the ground and this is not their first growing season in your landscape, one deep watering every week should be enough for them.

If they’re in a container or it’s their first growing season in your yard, water them 2 to 3 times each week during the drought.

Crowded Roots

Agapanthus actually kind of like crowded roots to an extent. This is why they make great container plants.

But at a certain point, they become so crowded that they’re unable to absorb water and nutrients properly. This is when they’ll start affecting the plant’s ability to flower.

In a container, it’ll usually take around 3 years to get to this point. In the ground, it takes longer. About 4 or 5 years.

This is when you should divide your plants. I cover dividing Agapanthus in detail in my Lily of the Nile care post.


A hard freeze can destroy an Agapanthus’ blooms. This is usually more of a concern with deciduous varieties (meaning they die back to the ground over the winter). Evergreen Agapanthus will usually just die completely if they experience weather that’s too cold for them to handle.

Deciduous Agapanthus can be damaged if they go through an extreme freeze that dips below 10-15 degrees Fahrenheit.

How do you combat this? It’s actually pretty simple. Just cover your plants with 4 inches of mulch after they die back to the ground. This provides a layer of insulation that protects your plants from harsh weather.

Be sure to remove this mulch in spring, though, once the threat of frost has passed. Otherwise, they may have trouble breaking through the mulch.

How Long Does It Take for Them to Flower?

Most Agapanthus will flower the first year in your landscape. Others may take up to 4 years. The ones that take years to flower are usually grown from seed, which is unusual. If you buy an Agapanthus from a garden center and it’s a specific breed, not an “assorted Agapanthus,” then it was cloned from another plant. These should flower either the first or second year in your yard.

So, you might wonder, why wouldn’t a cloned Agapanthus produce flowers the first year? The answer is that transplanting a plant into your landscape can be stressful. It has to get comfortable with the soil, sun exposure, general weather, and water levels.

If this proves to be too taxing for your new plant, they will focus on other things besides flowering. Usually, they will flower the following year.

Should You Deadhead Agapanthus Flowers?

In a word? Yes.

Deadheading Reblooming Lily of the Nile

It’s important to deadhead reblooming varieties. When I was in the nursery business, we grew several reblooming varieties from the Southern Living Plant Collection (such as the Ever Amethyst and Ever Midnight Agapanthus).

These guys bloomed early and they bloomed for a long time. They would start flowering in spring and rebloom regularly until the first frost of the year.

But to get the most out of them, you need to get those spent flower clusters out of their way. If you don’t, they shift their focus to developing seedpods. If you do snip them, they decide that they need to go ahead and bloom again.

In the picture below (courtesy of The Miscellanista) you can see several blooms aging and drying up at the bottom of the cluster. Wait until all of the flowers in the cluster have aged out like this and then snip off the stalk.

when do agapanthus flower and need to be deadheaded

Deadheading Non-Reblooming Varieties

Deadheading is still a good idea for non-reblooming varieties.

Removing Agapanthus flowers prevents them from producing seedpods that will sprout into new plants. You might be thinking, “Why wouldn’t I want free plants??” Well, the plants that would sprout from those seeds would not be like their parents. They wouldn’t have the same type of flowers or foliage. They would be much wilder and weed-like.

To briefly explain, if you bought a specific breed from a garden center, your plant was cloned from another plant that was cloned from another plant that was cloned from another plant. This goes all the way back to an original plant that first exhibited the traits that your plant has today, such as purple flowers, dense growth, etc. This is why your plant grows exactly the same as any other plant that is the same breed.

The plant that sprouts from one of your plant’s seeds will be nothing like this parent plant.

So rather than cluttering your garden with strange little Agapanthus plants that you’ll want to remove later, you can just deadhead the flowers after they’re spent.

Or you can leave them, it’s completely up to you.

Do You Cut Them Back After Flowering?

After flowering is the best time to trim deciduous Agapanthus. This way, you won’t be sacrificing future flowers. Leave about 4 inches of the plant sticking up from the ground to get a complete re-flush of foliage. On the other hand, Evergreen varieties can be trimmed up as-needed throughout the year.

If you want to harshly cut your evergreen Lily of the Nile plants back, do it in spring or early fall. Pruning makes your plant create new foliage. New foliage is vulnerable to extreme heat or cold. So if you trim them in summer, late fall, or winter, they may end up getting seriously damaged.

Wrapping Up: When Do Agapanthus Flower?

I hope I’ve thoroughly explored all aspects of the question “When do Agapanthus flower?” for you today.

If you still have questions, please leave a comment below and I’ll be sure to provide an answer as soon as possible.

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