Why Do Hellebore Flowers Last So Long?

Hellebores are all the rage right now and everybody seems to be adding more to their garden. A big appeal is the fact that they flower so early, sometimes even when there is still snow on the ground. But the real reason people like them is that they bloom a very long time; as much as five months.

Or do they?

They certainly seem to bloom for a long time; a closer look will reveal their secret. Once you understand why they bloom so long you will be able to select other plants that do the same thing.

When is a Flower Not a Flower?

When the general public looks at the colorful part of a plant, they call it a flower. Everyone is familiar with a poinsettia and the red part is considered to be the flower, which seems to bloom for many months.

Botanically speaking, the red part is not a flower. By definition a flower is the reproductive structure of the plant, which has organs such as stamens and a pistil, and it is enclosed in an outer envelope of petals and sepals.

The red part of a poinsettia are bracts (modified leaves), not petals. Inside each structure you will find numerous very small flowers. The petals are almost invisible.

Now lets have a look at a hellebore.

The Hellebore Flower

The picture below is Helleborus niger, from my garden, but the discussion applies to most hellebores including the common hybrids found in gardens. This species that produces very white flowers that look like so many other white flowers, but unlike other flowers, it lasts for months.

Let’s have a closer look. The white parts are not petals. They are actually sepals, which is the part of the flower you see when it is still in the bud stage.

If you look closer in the center, you can see some familiar structures. You can see the yellow pollen heads from the stamens and in the very center is the pistil.

Around the outside of this is an unusual structure that looks like a small tubular flower. These are nectaries, a modified petal that provide nectar to visiting pollinators.

Nectaries Warm Up the Flower

Hellebore nectaries contain natural yeasts which ferment the nectar. This fermentation produces heat, increasesing the temperature of the nectar and creating a warm micro-climate inside the flower.

Imagine a pollinator finding this warm spot in very early spring. Not only is it a warm place to sit, but a fermented beverage is on tap. No wonder hellebores are frequently pollinated.

Main Part of the Flower Lasts Two Weeks

Most perennial flowers last for one to two weeks and the hellebore is not that different. The picture below is the same flower, two weeks later. The stamens are collapsing – they’ve done their job.

The nectaries (modified petals) are falling off. You can see one sitting on the lower sepal.

The pistil seems to be growing, probably because it was fertilized. Over the next few weeks it will get larger and larger as the seeds develop.

The Sepals Are Here to Stay – For a While

The sepals will remain on the plant for several more months and this is why we consider them to flower so long.

Why do they do this?

The sepals are modified leaves and once fertilization takes place they start to photosynthesize. Their color changes to show more green, due to chlorophyll.

The persistent sepals are important for the development and maturation of the seeds, and that is why the plant keeps them. Once the seed is mature, they drop off.