Waterlilies don’t get tired, but many do go to bed at night.
Our hardy waterlilies at Splash are day bloomers. This means they will open in mid-morning and typically close in late-afternoon. Some tropical varieties, though, are night bloomers. They open in late afternoon and stay open all evening, finally closing as many people are heading to work for the day.
Each flower on a waterlily will repeat its bloom cycle for three to five days before dying and sinking into the water. With plenty of sunlight and fertilizer, most lilies will produce tons of new flowers throughout the season from May until October in southcentral Pennsylvania (Zone 6).
Not sure which type of waterlily is right for your pond, or want to know why your lilies don’t seem to bloom when they should? Read on …
At a Glance: When Do Waterlilies Bloom?
- Hardy waterlilies usually bloom from mid-morning to mid-afternoon.
- Some tropical waterlilies bloom from late afternoon to early morning.
- Each flower lasts three to five days.
- New flowers grow throughout the spring and summer.
How Do I Get My Waterlily to Bloom?
You’ve picked out some beautiful lilies for your pond. Now it’s time to make sure you’re getting the most blooms for your buck.
Waterlilies are voracious eaters, meaning they need plenty of fertilizer to perform their best. We recommend using two once-a-month fertilizer tablets per plant during the growing season.
They also need as much sun as possible – at least seven hours is ideal for most varieties – although some will tolerate partial shade.
Place your lily so that the base sits around 10 to 30 inches under the water – about 24 inches is ideal. You can either keep the plant in its pot, move it to a fabric aquatic planter or plant it in the stones or a designated pocket in your pond. Either way, make sure to divide your lily periodically to prevent overcrowding and ensure maximum blooms.
Hardy vs. Tropical Waterlilies
Almost all hardy waterlilies sold in the United States bloom during the day. Tropical lilies, on the other hand, can bloom during the night or during the day, depending on the variety.
So what’s the difference between a tropical and hardy waterlily?
Hardy waterlilies can survive the winter outside throughout much of the United States, going into a dead-looking dormant state as temperatures cool before springing back to life as the weather warms. Tropicals will die completely in cold temperatures in all but the most southern parts of the country. This means you will have to bring your tropical waterlily inside over the winter or, like most people, treat it as an annual and replace it the next year.
Tropical waterlilies do have their advantages. Their flowers usually look noticeably flashier than their hardy counterparts, displaying a range of colors – including blues and purples – and unique shapes. Their blooms tend to rise 6 to 12 inches above the water instead of floating on top like a hardy lily, and they often produce larger and usually more aromatic flowers. These differences – as well as the added difficulty of growing tropical plants in the North – tend to make tropical lilies slightly more expensive than hardy ones.
If you want a flower that you can enjoy after work at night, a night-blooming tropical might be the right choice. But if you want something that will stay awake during the day, choose a hardy lily or day-blooming tropical. And if you want both, why not pick a few types of lilies? The larger the variety of plants in your pond, the less likely you are to have problems with algae.
Why Do Waterlilies Close at Night?
Making flowers is hard work. That’s why your waterlily doesn’t keep its blooms open 24/7.
If a waterlily needs day-dwelling bees and birds to pollinate it, it will only open during the day. Closing at night might protect the flower from night-lurking plant-eaters or nighttime frost, as well as prevent pollen from getting too wet with morning dew.
No one knows for sure why some tropical lilies prefer to bloom at night. Scientists guess that these kinds of plants want to attract specific nocturnal pollinators, like moths and bats. The practice might also protect the flowers from the extreme heat in tropical climates.
Regardless of when your waterlily blooms, the leaves will continue floating on top of the water throughout the growing season. That means even a night-blooming waterlily will help protect your fish from harsh sun and predators.