It’s a big dill … for food and fauna

If you have ever had the opportunity to attend Will County Farm Bureau’s Ag Expo (by the way, if you haven’t, watch for it next year), you have heard me ask teachers and the class what the difference between an herb and a spice is.
Most people think they are interchangeable terms, but they aren’t! Herbs are the leaves of plants, and spices are any other part: seed, stem, trunk, flower, etc.
But a few plants are lucky to be both; one of those is the amazing, easy to grow, delicious in many recipes and … wait for it, great for certain butterflies, dill!
Dill is a reseeding annual herb and spice. The herb is the fine cut leaves of the dill plant imparting a gentle, fresh flavor to many dishes but particularly cucumber recipes and fish dishes.
The spice part of dill is the dill seed used usually in dried form as the keystone ingredient in dill pickles.
There are several dill varieties to choose from, depending on which part of the plant you are more interested in. The old-fashioned dill puts on leaves in the spring and early summer, but by July, the leaves have dried up and the umbrella shaped seed heads (botanically called umbels) are developing.
Preserving the harvest through canning and fermenting were necessary skills in early America, so the dill seed heads were the focus.
Newer varieties of dill focus on a longer production of the leaf stage of dill. Some of these varieties are Bouquet, Fernleaf, Dukat, Greensleeves and Super Dukat.
Growing dill couldn’t be easier. You can purchase plants, but dill grows very easily from seed. As with most every plant, fertile, well-drained soil is ideal. Dill also grows well in containers.
To harvest dill, snip the stems just above the soil line with scissors or pruning shears. For fresh dill, you can store the cut stems in a glass of water with a plastic bag over the top in the refrigerator for a few days. To preserve dill for longer, you can freeze it or dry it.
Dill seeds can be harvested when the flower heads turn brown and dry, and can be stored in an airtight container in a cool, dry place.
Dill likes sun, and although the instructions on the seed packet show growing it in rows like vegetables, I just sprinkle dill seeds around my garden and let them come up where they will. So, there is enough for everyone, me, and the caterpillars. Dill is the “baby food” of the Eastern Black Swallowtail Butterfly.
Just like with people, kids can be fussy eaters. Same is true to the ultimate degree for butterflies … well their babies. Our butterflies lay eggs on a specific plant or plant family, and these are the only plants that their larvae can survive and thrive on.
Take the classic example of the Illinois State Insect, the monarch butterfly. It is well known that monarchs only lay eggs on milkweed. What is not well known is there are 14 kinds of milkweed native to Illinois, and all of them support monarchs, not just the extremely invasive common milkweed.
For the Eastern Black Swallowtail butterfly, she lays her eggs exclusively on plants in the Apiaceae family also known more commonly as the carrot family. These plants include dill (Anethum graveolens), fennel (Foeniculum vulgar), carrot (Daucus carota, subspecies, sativus), parsley (Petroselinum crispum) and the weed, Queen Anne’s Lace (Daucus carota).
And yes, if you were wondering, the carrot we eat today is a cultivated relative to Queen Anne’s Lace.
I always get several calls each year from homeowners upset that their carrot leaves are being devoured by “some worms.” Many a client changes their perspective when they learn those little worms are actually soon to be Eastern Black Swallowtail Butterflies.
The Eastern Black Swallowtail Butterfly starts out as a tiny yellow egg on the tiniest of all dill leaves, and soon turns into a “bird poop looking” small caterpillar. This butterfly goes through five stages called instars, and in each, they look a little different. See photos above.
A single female Eastern Black Swallowtail can lay between 200-400 eggs (singly, one at a time) in her short two-week life span (six to 14 days). This butterfly does not migrate like the monarchs do, but rather overwinters in their chrysalis here.
Some nature-loving people choose to overwinter these chrysalises (or chrysalids) in their garages. Just be sure it stays as cold as outside, because I have seen several posts of well-intentioned folks showing their freshly emerged adult butterflies long before there are any plants out to feed them.
The temperature where the chrysalises overwintered had become too hot, spurring on the unavoidable process of nature.
The good news is we have at least two generations per year during the summer. If you want to share your love of nature with your family, particularly young ones, this butterfly is a great one to observe.
The Black Swallowtail also teaches another nature lesson, that of mimicry. Appearing to resemble another insect that is poisonous to predators. In the case of the Eastern Black Swallowtail, they look extremely similar to the Pipevine Swallowtail.
Like with monarchs that consume milkweed that is poisonous to birds, but not to the caterpillar, the viceroy butterfly changed its appearance over thousands of generations to appear similar to the poisonous monarch.
Similarly, the Eastern Black Swallowtail, which is not poisonous to predators, looks remarkably similar to the Pipevine Swallowtail. Nature, always amazing.
One other note about dill and one other member of the carrot family, fennel: Dill and fennel should not be planted close to each other, because they cross pollinate and the seeds that germinate next year and create plants with a mixed blend of dill-fennel flavor.
I thought that would be interesting. It was not … and the flavor was dilute and not really palatable.
Interestingly, fennel, the licorice-flavored herb, doesn’t play well with most other plants and is better left isolated alone. Some plants (like black walnut and fennel) cause allelopathic reactions. Think of it as a crabby neighbor saying, “Get out of my yard!”
Allelopathic plants release chemicals that can inhibit the growth of other plants near them. For fennel these are beans, tomatoes and eggplant.