Golden Alexander Hosts Black Swallowtail Butterflies!

Golden Alexander’s (Zizia aurea) umbrella shaped clusters of tiny sunshine yellow flowers have been lighting up my shade garden for weeks, and will continue for a while longer.

Golden Alexander

Golden Alexander

Like so many plants, Golden Alexander responded to the unusually warm winter and early spring temperatures by blooming a few weeks earlier than normal.  When the flowers are pollinated, dry fruit capsules replace them, an attractive feature for many weeks to come.  Golden Alexander’s rich green foliage is visible for much of the year. 

The bright yellow flower umbels help identify Golden Alexander as a member of the parsley or carrot family, and a food plant for the caterpillars of Black Swallowtail butterflies.

Male Black Swallowtail perching

Male Black Swallowtail perching

Other members of this family include parsley and dill, which Black Swallowtail caterpillars will also readily consume.   Adult butterflies will visit a variety of flowers for nectar, but their caterpillars can only eat parsley family members, and rues.

Members of the parsley family contain natural chemicals that can be toxic, a defense mechanism the plants use to deter their consumption by potential predators, from insects to mammals.  But Black Swallowtail caterpillars have a special ability to detoxify the chemical, and eat the plants.  The chemical helps protect the caterpillars from being eaten by making them distasteful to predators, such as birds.

Black Swallowtail caterpillar with shed exoskeleton from its previous instar (growth stage).

Black Swallowtail caterpillar with shed exoskeleton from its previous instar (growth stage).

Golden Alexander’s bright flowers entice a variety of beneficial insects to forage for nectar and pollen, and at the same time, assist in pollination.  Visitors include a variety of early bees, wasps, flies, beetles, and small butterflies.  There is one bee species, Andrena ziziae, named after its preference for this plant.

Insect pollination isn’t a given, though.  These pollination partners have to evade the clutches of predators who would like to eat them, including spiders, and assassin bugs, like this cleverly disguised Zelus luridus.  So Golden Alexander has self-polination as a back-up strategy.

Golden Alexander with Zelus luridus, an assasin bug

Golden Alexander with Zelus luridus, an assasin bug

Golden Alexander (Zizia aurea), and the similar looking Heart-leaved Alexander (Zizia aptera) reach a height of 1-3 feet.  They can tolerate sun to at least part shade, and like somewhat moist soil.  I have them in a shaded bed along the edge of a driveway. They have adapted very well, and are very easy to grow.  Golden Alexander will spread readily from seed, and in my garden, it is not preferred by deer.  Always a good quality!

4 thoughts on “Golden Alexander Hosts Black Swallowtail Butterflies!

  1. Hi Mary Anne, Any advice on where to get this plant. Haven’t seen any locally. I have plenty of shade and would love to get them. Really enjoy your posts! Thanks, Bobbie

    • Hi Bobbie,

      If you can’t find it at your local garden center, some possible sources for this plant are:

      Bowman’s Hill Wildflower Preserve (buy it in person there; as a bonus you get to wander the wonderful trails!)
      Toadshade Wildflower Farm (a great mail-order source of plants for the northeastern U.S.)
      Prairie Moon Nursery (a great mail-order source of plants for the midwestern U.S.)
      Missouri Wildflower Farm (also great for the midwest)

      The Native Plant Society for your state or region will often have lists of nurseries that are good sources of plants. For example, the Native Plant Society of New Jersey offers this list: http://www.npsnj.org/pages/nativeplants_Plant_Lists.html

      If all else fails, do an internet search for ‘native plant nursery’ and your state, or for the plant, in this case Zizia aurea. It’s safest to use the Latin name when searching for a plant, since there may be different common or English names used for the same plant in different regions, or more than one species of plant may be known by the same common name.

      Hope that helps!

      Mary Anne

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