7 Best Dill Plants For Attracting Swallowtail Butterflies Gardeners Swear By

You’ve planted dill hoping for pickles and a few beautiful butterflies, but instead, you find your plants stripped bare overnight by a dozen hungry caterpillars. This isn’t a failure; it’s a sign you’ve successfully created a habitat. Choosing the right dill variety isn’t just about your kitchen needs, but about managing this beautiful, natural partnership with Black and Anise Swallowtails.

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Why Swallowtail Butterflies Adore Dill Plants

Swallowtail butterflies don’t just randomly land on dill. They are specifically seeking out plants in the Apiaceae family—which includes dill, parsley, fennel, and carrots—as host plants for their young. These plants contain specific chemical compounds that are essential for the caterpillars’ development and defense.

When a female swallowtail finds your dill, she’s not there to sip nectar. She’s looking for the perfect place to lay her eggs. She can identify the right plant by its scent and by "tasting" it with her feet.

Once the eggs hatch, the tiny caterpillars emerge with a voracious appetite. They will munch exclusively on the foliage of these host plants, growing rapidly through several stages, or instars. The dill you plant is their entire world and food supply, so a healthy, leafy plant is crucial for their survival into the chrysalis stage and beyond.

‘Bouquet’ Dill: The Classic All-Purpose Choice

‘Bouquet’ is the dill most people picture. It’s the dependable, go-to variety found in garden centers everywhere for a reason: it does everything reasonably well. It produces a good amount of fragrant foliage for caterpillars and your kitchen, and it develops large seed heads perfect for pickling.

Think of ‘Bouquet’ as the generalist of the dill world. It grows to a moderate height of about three feet, making it manageable in most garden beds. Its balanced growth means you can often harvest some for yourself while still leaving plenty for the caterpillars, especially if you plant a small patch instead of a single plant.

However, its biggest strength is also its weakness. Because it’s bred for both leaves and seeds, it will eventually "bolt," or send up a flower stalk, especially as the weather gets hot. Once it bolts, leaf production slows dramatically. For a continuous supply for both you and the butterflies, you’ll need to succession plant ‘Bouquet’ every few weeks.

‘Fernleaf’ Dill: Best for Containers & Small Spaces

If your gardening space is a patio, balcony, or a few pots, ‘Fernleaf’ is your answer. This is a true dwarf variety, typically staying under 18 inches tall. Its compact, bushy habit makes it exceptionally well-suited for container gardening where taller varieties would quickly become top-heavy and fall over.

The key tradeoff with ‘Fernleaf’ is its size. While it produces dense, attractive foliage, there’s simply less of it. A single ‘Fernleaf’ plant can be completely devoured by just two or three large swallowtail caterpillars in a matter of days. This isn’t a bad thing, but it requires a different strategy.

To make it work, plant several pots of ‘Fernleaf’. This creates a "dill buffet" you can rotate. As caterpillars strip one plant, you can move them to a fresh one, giving the first plant time to recover. It’s also slower to bolt than many standard varieties, which is a significant advantage in the confined, often warmer, environment of a pot.

‘Mammoth’ Dill: For a Large Caterpillar Feast

As the name suggests, ‘Mammoth’ (sometimes sold as ‘Long Island Mammoth’) is all about size. This variety can easily reach five feet tall or more, creating a massive, sprawling plant. If your primary goal is to raise a large number of swallowtail caterpillars, this is the variety to plant.

‘Mammoth’ produces thick stalks and an enormous amount of feathery foliage, providing a feast that can support a dozen or more caterpillars simultaneously. Its sheer volume means you’re less likely to see your plants stripped bare overnight. It’s also a fantastic producer of huge seed heads, making it a top choice for serious picklers.

The downside is its space requirement. This is not a plant for a small, tidy bed. It needs room to grow and will likely require staking to prevent it from flopping over in wind or heavy rain. Its rapid growth also means it’s eager to bolt and set seed, so it’s best for gardeners who want a single, massive crop rather than a season-long supply of tender leaves.

‘Dukat’ Dill: A Flavorful and Leafy Host Plant

‘Dukat’ is a standout for its high essential oil content, which makes it exceptionally flavorful and aromatic for culinary use. But that same quality also makes it highly attractive to swallowtail butterflies. It’s a rich, dark blue-green color and produces an abundance of foliage before it thinks about bolting.

This variety is an excellent middle-ground choice. It’s leafier and slower to bolt than ‘Bouquet’ but not as massive as ‘Mammoth’. This makes it a perfect dual-purpose plant for the average garden bed. You can harvest plenty for cooking while leaving a substantial amount for caterpillars.

Because it focuses its energy on leaf production, it’s a reliable food source for a longer period. Caterpillars get a nutrient-rich meal, and you get a superior herb. If you want one dill plant that excels for both the kitchen and the butterflies without compromises, ‘Dukat’ is a strong contender.

‘Hercules’ Dill: Slow-Bolting for a Longer Season

The biggest frustration for many dill growers is bolting. As soon as summer heat arrives, many varieties abandon leaf production and shoot up a flower stalk. ‘Hercules’ is specifically bred to resist this urge, making it a champion for a long, continuous harvest.

This slow-bolt characteristic is a game-changer for butterfly gardeners. It means the plant remains a viable, leafy food source deep into the summer, long after other varieties have gone to seed. This is crucial for supporting later generations of swallowtails that emerge in mid to late summer when other host plants may be scarce.

While ‘Hercules’ will eventually flower, it gives you a much wider window of lush foliage. This makes it ideal for gardeners in hotter climates or anyone who doesn’t want to bother with succession planting. You plant it once and get a reliable food source for months.

‘Vierling’ Dill: A Reliable Late-Season Option

‘Vierling’ is another slow-bolting variety, but it has a slightly different growth habit that makes it particularly valuable. It tends to be more compact and bushier than ‘Hercules’ but with the same reluctance to flower. This makes it a sturdy and productive choice for late-season caterpillar support.

Think of ‘Vierling’ as your insurance policy for the last wave of swallowtails in late summer and early fall. Its robust nature means it holds up well through the stresses of late-season weather. The foliage is plentiful and remains tender longer than many other types.

By planting ‘Vierling’ alongside an earlier-season variety like ‘Bouquet’, you can create a seamless, season-long habitat. The ‘Bouquet’ feeds the first generation of caterpillars, and just as it begins to fade, the ‘Vierling’ is hitting its stride, ready to host the next.

‘Superdukat’ Dill: Maximum Foliage for Caterpillars

If ‘Dukat’ is prized for its flavorful leaves, ‘Superdukat’ takes that a step further by focusing almost entirely on foliage production. This improved strain offers an even higher leaf yield and is also very slow to bolt, combining the best traits of a leafy and a long-season variety.

For the dedicated butterfly enthusiast, ‘Superdukat’ is a top-tier choice for maximizing caterpillar food. It produces dense, heavy foliage on a plant that stays productive for a very long time. It provides the fuel needed for a healthy, thriving caterpillar population.

The tradeoff is that it’s less focused on seed production than a variety like ‘Mammoth’ or ‘Bouquet’. If your goal is a big harvest of pickling seeds, this isn’t the best option. But if your priority is a lush, leafy, and long-lasting buffet for swallowtails, ‘Superdukat’ is hard to beat.

Ultimately, the best dill is the one that fits your garden space and goals. Don’t be afraid to plant two or three different varieties to serve different purposes. By understanding their unique traits, you can move from being a passive host to an active manager of your garden’s beautiful ecosystem.