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What’s Blooming in Paradise: Senna perfect host plant for sulphur butterfly

By Staff | Nov 11, 2015

The senna produces five petals of creamy yellow flowers. ANITA FORCE MARSHALL

Plant Subject: Senna (Senna mexicana var. chapmanii or Senna ligustrina)

First impression: Sunny shades of creamy yellow, five petal flowers that remind me of old fashioned buttercups. I can’t help but notice yellow butterflies in all sizes fluttering around. They are so similar to the blossoms; they are mistaken for flying flowers. Need a little zip pe dee doo dah IN your life? Come see bouquets of buttercups bursting all over our bushes at the Botanical Gardens of the Sanibel Moorings.

Upon further investigation: Three reasons why sulphur butterflies populations are dwindling: senna, senna, and senna! Our under used garden stars are the host plants for several species of sulphur butterflies. A host plant is the one plant that each species of butterfly will lay their eggs on and is essential for their survival. Mother sulpher utilizes senna to lay oodles of single, elongated, paleish white eggs right on the tender new leaves. As the newborn caterpillar hatches, its mission is to eat and eat and eat. The sulphurs are a curiosity to watch. They are a green color if they consume the green leaves and yellow when their choice of food is the yellow flowers. You can truly say they are what they eat! Eventually, the caterpillars grow larger and fatter and one day travel to a safe spot and begin their chrysalis and metamorphosis

Senna flowers are small, about an inch across, and appear in clusters at the end of leafed branches. The sweet tasting flowers do double duty and also serve as a nectar plant. Leaves are pinnate, soft and make the plant attractive even without flowers. The fruits are green-bean shaped shaped pods, 3-4 inches long, and eventually split open to release teeny tiny seeds. Plant in partial shade to full sun in a well drained area.

I began my love of both seines, with my first plants, which I purchased from the SCCF Native Plant Nursery. Their native status puts it in the easy care and lack of pests/disease category. They are made for our tropical climate with drought tolerance and need for full sun. I recommend planting both varieties, they are so similar; but do flower at different times.


Once you plant them in your garden, prepare yourself for the nibbled leaves and stripped stems, which is a result of the never ending eating caused by sulphur caterpillars. I nestle my sennas in between other nectar plants (aka flowers), which helps hide the stubs and its unsightliness. Once the plants are without leaves, or the caterpillars have moved on, new growth is fairly fast and ready for the next hungry caterpillars. Gentle reminder: butterfly gardeners have to re-evaluate pesticides as their use will interrupt the life cycle of the butterfly which is egg, larva, pupa and butterfly.


Buttercups galore

Does well in sandy soil

We can all use more butterflies

Likes full sun

Host plant for a many butterflies

Pollinators love it

Native plant

Oodles of butterflies fluttering all around it.


Seed pods need to be trimmed away

Can get leggy and twiggy

Pollinators love it

Re think/tolerate caterpillars and nibbled leaves

May give you the urge to eat more butter

Conclusion: Being beautiful, must be nice, how could anyone say ‘no’ to such a gorgeous butterfly? Now we have the perfect host plant that does double duty as the perfect flower in our tropical eye catching garden. Don’t wanna miss this bloomer!