Today is a celebration of two of our favorite butterfly-attracting herbs, fennel and dill. Fennel and dill are one of the reasons we like to advise planting some herbs for yourself to enjoy and some to offer the pollinators. Once the butterflies scout these out in your landscape, they are likely to head your way in droves.

Fennel and Dill

Fennel and dill look remarkably similar.  They both have fine-textured, feathery leaves that are topped with umbels of tiny yellow flowers at maturity. However, a quick sniff or taste test will highlight one of their differences. Fennel emits a fresh anise aroma and has a sweet licorice taste while dill has the aroma and tangy taste of dill pickles (hence the name). The leaves, seeds, and oil of both herbs are used, but with fennel, you can also eat the bulbs.

When researching fun facts about using these herbs medicinally, I came across two that I find particularly entertaining. One is that dill is an ingredient in “gripe water” a product that is used to aid babies with indigestion. The second is that William Coles (botanist circa 1600s) wrote about fennel that it is “used much in drinks and broths for those that are grown fat, to abate their unwieldness and cause them to grow more gaunt and lank.” LOL! I guess that is another way of saying you can make a diet tea out of it. (Always consult your doctor before beginning a medicinal herb program for your health.)

Dill adds delicious flavor when pickling cucumbers for pickles, added to potatoes, or to brighten up potato and egg salads. Raw fennel thinly sliced adds a sweet crunch to salads. Braising or roasting fennel softens the anise flavor and makes a delicious side vegetable for seafood dishes. The entire plant of fennel is edible.

Potatoes with herbs on top.
Herbal tea in a cup.

Both fennel and dill look great in the landscape with their fine-textured, feathery fronds, but my favorite similarity of these herbs is that they are excellent host plants for Swallowtail butterflies! These tiny white eggs that are laid atop and under the leaves of dill and fennel hatch in about 3-5 days. Swallowtail larvae emerge to happily munch the foliage. Again, this is why we say buy some for the pollinators and some for you. The abundance of yellow flowers these herbs both produce attract many other beneficial pollinators as well. We advise getting to know what larvae of butterfly and other beneficial insects look like so you don’t accidentally spray the good guys while trying to get rid of the bad guys.

The frond of dill and fennel
Caterpillar on fennel

Tips for Growing Dill and Fennel

Fennel is a perennial and dill is grown as an annual, but both will readily reseed. Fennel can reach heights of 4-6  ft. (possibly taller) while dill generally hits heights of about 2-3 ft. While both herbs are easily propagated by seed, it is generally recommended that you plant seeds of dill in spring and seeds of fennel in fall. However, they are both available as transplants in both spring and fall at Rainbow Gardens. 

Dill is more of a cool weather herb; spring and fall are its best seasons. Once the heat rolls in, dill will go to seed and dies out. If its seeds are left to fall and go undisturbed, dill will pop up again when the weather begins to cool. Fennel will continue growing throughout the year, even surviving winters when they aren’t too severe. Cutting it back multiple times throughout the year helps keep the size of fennel in check. 

Grow both herbs in sun to part sun. Do not grow them close together as they tend to cross pollinate, resulting in a poor taste. If you want to plant them in the same garden, make sure to have a few rows of other crops in between them, or plant in pots that you can keep separated. Soil should be rich in organic matter and most of all well-draining. Hold off on fertilizing plants until they are well established. If growing fennel for the bulb, cover the bulb with mulch or soil as it develops to keep it tender. (Tip: Florence fennel produces the largest bulbs.)

Giant Swallowtail Butterfly
Swallowtails love plants in the carrot family for host plants.

Dill and fennel are easy pollinator friendly plants to grow. Whether you choose to try one or both of these herbs, we think they will be a favorite in your landscape for years to come. Bring on the butterflies!

~The Happy Gardener, Lisa Mulroy