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Agapanthus, also known as the African lily and Lily of the Nile can still add visual interest to your garden after flowering. They can be productive in several ways, including through the use of their seeds for future flowers but also to add some visual interest after flowering.
Agapanthus are one of my favourite perennials. Here are 6 things you can do after or not do after flowering, starting with the do’s and don’ts of deadheading the flowers. I also have a short section towards the end, which includes what to do with agapanthus grown in pots after flowering.
The short answer to what to do with agapanthus after blooming is either leave them on to add some winter interest or cut the flower stalks back to stop them from self-seeding. However, there a lot more to learn, so read on to learn more.
Why and how to deadhead the flowers
Deadheading agapanthus flowers after they’ve finished blooming keeps the plant looking clean and tidy, but it doesn’t really encourage more flowers, like on some perennials. It also prevents the seed heads from forming, which can encourage a stronger and better root system.
Deadheading involves cutting off the blooms at their base. Use a sterilised cutting tool that’s sharp, I usually use a good sharp pair of secatuers, but you can also use a pruning/gardening knife. You want to make a clean cut when you do this task. Having to hack at the stem several times to take the bloom off leaves an open wound that’s an easy entry point for fungal diseases such as crown rot.
You’re probably taking off several blooms at once, and sterilising your cutting tool (use alcohol wipes) between cuts stops any diseases from being moved around the plant.
Why not let the seed heads develop
The spent blooms develop into seed heads. This adds a different look and shape to your plant, continuing its visual appeal into the autumn. This is why I usually leave a few seed heads on even if I cut 50-60% of them back at the base.
Collect the seeds for even more plants
If you let the seed heads fully develop (or some of them), they create seeds inside them that you can collect and sow to develop new plants. To store these seeds until the right time, gently pick off the whole seed head and put it into a paper bag. It’s better for the seeds if you let the seed head ripen on the plant. Germinate the seeds over winter for picking out and transplanting the next growing season. It’s worth mentioning that it can take a few years for agapanthus grown from seed to flower, but if you have the space and patience it can be well worth it.
Leave the seed heads on
If your agapanthus plants are in the ground in your garden and you’d like a few more to develop, leave the seed heads on. The seed heads eventually burst or fall to the ground. In both cases, the seeds are spread, and some may take root for next year. Of course, this leaves the development of any new agapanthus up to nature’s chance and the weather, rather than collecting the seeds and germinating them yourself. If you have dense patches of agapanthus, you may want to think about removing teh seed heads to avoid this.
Cut the agapanthus back, including the leaves
After the blooming period is over, you have the choice of cutting back the agapanthus, it’s usually once the leaves become yellow. However, if this happens early on, see my guide here on why agapanthus gets yellow leaves. You can do it at the end of autumn or the beginning of winter to have a clean landscape for the snow. However, you can wait until the next spring to cut back, which is what I usually do. The dead agapanthus leaves and stems provide warmth to the soil and the roots over winter, giving them a little more protection. This also adds some visual interest to an otherwise bleak landscape.
If you have any issues with poor flowering, check out this guide on why agapanthus sometimes don’t flower very well.
Bring your potted agapanthus inside
If your agapanthus is growing in a pot, think about bringing it inside for the winter, especially evergreen varieties. This is how evergreen varieties survive the cold months – deciduous types are hardier. Make sure that the temperature of the agapanthus’ new environment is to their liking (see How to grow and care for agapanthus plants) and cut down on the watering schedule. I also have a dedicated guide on growing agapanthus in pots here.