By: Mary Townsley, Mobile County Master Gardener www.mobilecountymastergardeners.org
As I work in my garden, I always wonder how I can attract more butterflies. Is it just about providing more nectar sources? Can I just plant more of the "plants for pollinators" that I already have? Or is there more to consider?
More than 50 species of true butterflies have been documented in Mobile County (https://alabama.butterflyatlas.usf.edu), bringing interesting color to our landscapes as they swoop, flit about, and feed. I have focused on a few species to highlight the similarities and differences in their habitat needs, including swallowtail and cloudless sulphur butterflies (sighted in our county throughout most of the year) as well as monarchs, zebra longwings, and Gulf fritillaries (more common in the late summer/fall months).
Most butterflies are not picky about which flowers they collect nectar from. One interesting difference is that cloudless sulphurs have a much longer proboscis (a straw-like mouthpart) than other butterflies, so they can collect nectar from long-tubed flowers. Think of those flowering plants that hummingbirds like; you will likely see cloudless sulphurs feeding there, too.
However, having a variety of flowering plants, trees, and shrubs in your landscape providing nectar sources throughout the year is just the first step in creating a welcoming habitat for butterflies. If you want them to set up shop rather than treating your landscape plantings as a fly-through food source, you will want additional plantings serving as hosts for butterflies’ eggs and for the hatched larvae (caterpillars) to eat. That's where your thoughtful planning will be important.
Black swallowtails use a wide variety of plants in the carrot/parsley family as their caterpillar hosts. For example, pair spring-blooming Golden Alexanders with Queen Anne's lace (wild carrot) that will bloom in summer through fall. Adding fennel (the ornamental bronze fennel or the edible Florence fennel), carrots and/or parsley to your vegetable garden will also satisfy these butterflies.
If you have citrus trees in your landscape or in patio pots, you are set with host plants that will support giant swallowtails. Satsuma, grapefruit, Meyer lemon and kumquat trees are good choices for these large butterflies.
The eastern tiger swallowtail, the Alabama state butterfly, is more of a generalist. This butterfly will use a variety of trees such as tulip poplars, sweet bay magnolias, ashes, and black cherry as caterpillar hosts.
Cloudless sulphur’s host plants include members of the pea family, especially partridge peas and sennas. Senna bicapsularis (also known as winter cassia or butterfly bush) is a nice choice to plant: it flowers profusely in late fall/early winter, providing both late season color and plenty of butterfly/caterpillar food.
Milkweeds (Asclepias spp.) are the only hosts for monarch butterflies. Plant milkweeds native to our area if you can find them, such as butterfly milkweed (A. tuberosa) and swamp milkweed (A. incarnata). If you do grow tropical milkweed (A. curissavica), either remove it or cut it down to the ground in early fall to encourage the normal monarch migratory behavior. Voracious monarch caterpillars will do this for you, but be vigilant, as tropical milkweed readily self-sows.
Both zebra longwings and Gulf fritillaries use passion flowers (also known as maypops) as their hosts. I have not planted passion flowers in my yard, but my neighbors must have, as I see both butterflies visiting my nectar plants. I think adding purple (full sun) or yellow (shade) passion flowers to my landscape will be my next step to support these gorgeous butterflies.
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