The Secret Lives of Carrots

Most gardeners grow carrots for the edible tap root: one growing season and done. But, left to their own devices, biennial carrots have a secret, second life beyond the colorful root vegetable we love so well.

Carrots – botanical name Daucus carota L. – are fascinating plants, far beyond what their rather non-descriptive (but colorful) taproots hint at.

Carrots are neither annuals nor perennials. Rather, they’re biennials. Meaning, they have a two-year life cycle.

What is a Biennial Vegetable?

Biennial vegetables have two-year – or two growing seasons – life cycles, where they produce edible fruit in the first year and then seeds in the second year.

Once the plant finishes producing and distributing its seeds in the second year, it dies, relying on the seeds to carry on the propagation of the species. Carrots are biennial vegetables.

How Do Carrots Grow?

The first year: Activity in the first growing season happens much as we gardeners expect:

• Sow the carrot seeds;
• The seeds sprout;
• The edible taproot develops and expands underground;
• Beautiful, ferny foliage thrives above ground to nurture the taproot;
• Once formed, the carrot can be harvested at any time, from a tiny baby to a wonderous mass with offshoots and shapes that go famously viral on the interwebs.

Note that the carrot is a fully “nose to tail” vegetable: the foliage is edible, too. Herbaceous and astringent, chop up the leaves into green salads or add to basil pesto, a chimichurri sauce, or hummus. Saute the thicker stems with onions, celery, and carrots (!) for a delicious soup base.

The second year is when things get interesting for seed savers and botany nerds like me.

When a fully grown carrot taproot is left in the ground over a cold winter, the plant will regenerate in the spring.

But instead of producing a carrot, the plant now concentrates on producing seed:

• The taproot sends up a shoot above ground;
• The shoot branches out and produces beautiful, intricate white flowers;
• The flowers form seeds – schizocarps, actually – which eventually dry out and blow away to reset themselves in the ground for the next generation.

Now you know where carrot seeds come from!

The Carrot’s Second Year

Let’s take a closer look at what happens during the second year of a carrot’s lifecycle.

I discovered this first-hand, quite accidentally, when I overlooked numerous carrots at the end of one summer’s harvest. The hearty deer population here absolutely adore carrot tops, and soon after I removed the fencing, they chomped the greenery down to the soil (which is how I lost track of all the carrots).

That particular carrot bed was slated to rest the next growing season, so I left the ground – and the hidden carrots below – undisturbed.

I was quite surprised the next spring when the bed erupted into life with the first bit of warm weather. Sprouts, everywhere.

Because I had no plans for the bed, I let nature take its course, eager to see what would happen. And, oh, what a show it put on.

Carrot Flowers

Most people have never seen carrot flowers, although no doubt have seen the carrot’s botanical relative, the near-twin Queen Anne’s Lace, growing along highways and fields.

The goal of the second year’s sprouts mentioned above is not to produce a delicious carrot, but rather a flower that yields seeds. It sends up only sparse stalks from the root of the plant — the unharvested carrot from the previous season. No luscious foliage like the previous season, as the plant is channeling all of its energy to the bloom.

For sheer showmanship, those flowers are worth the wait and the foregoing of the edible root the year before. Let’s take a closer look at a carrot flower.

This gorgeous specimen below is the first flower that bloomed on the plant, called the King Umbel. He’s not only the first flower but is always the largest flower and most prolific seeder. Here, 6″ across and densely packed with blooms.

Carrot flowers are made up of dozens of umbellets — the small rounded clusters you see above, consisting of tiny pollen-producing blooms.

Fun fact: Queen Anne’s Lace is actually a wild carrot, inedible to humans. Its umbels are very similar to carrot flowers, as mentioned, but with one notable exception: there is almost always one bloom in the center of the umbel that’s purple.

And here’s the King from the back with its fascinating structure clearly visible:

Like most flowers, carrots are not self-pollinating and rely on insects to move pollen from flower to flower in order to produce seed. Fortunately, these showy blooms easily attract bees and other flying insects.

The Formation of Schizocarps

Once the bloom starts to produce seed, it enters an interesting — to botany nerds, at least! — stretch of development.

As the schizocarps form — the structure that contains the tiny carrot seeds — the bloom makes every effort to both protect the schizocarps and maximize their distribution into the environment.

Let’s take a closer look at the seed head in its various stages.

In the photo above, you can see that the white blossoms have fallen away and the ones that have been pollinated are starting to form spiky schizocarps which contain mericarps and seeds within.

When mature, these schizocarps will release from the plant and scatter to the ground. They’ll be easily carried away by the wind or hitch a ride on a passing animal.

Until then, the seed head will protect these precious schizocarps from adverse weather by doing a thing called “bird’s nesting”: the bloom inverts inward to form a protective bowl.

In the profile photo above, you can see the umbellets curving inward to form the bowl that protects the seed store as the schizocarps continue maturing.

Many weeks later — the entire drying process can take a couple of months, depending on the weather — the seed head has dried and is ready to disperse the schizocarps and the seeds within:

Seed collectors can then pluck off the schizocarps and remove the spiky outer covering to access the mericarps and tiny carrot seeds inside.

I hope you’ve enjoyed this peek into the second year of a carrot’s growth cycle!