Plant of the month, Golden Alexander

There are two species of golden Alexander commonly found in garden centers. The common golden Alexander, Zizia aurea, and the less common heart leaved golden Alexander, Zizia aptera. The difference between the two is that aptera has compound leaves at the base while aurea has simple basal leaves. Aurea also prefers drier soils. Zizia is in the carrot family which includes dill, parsley, carrot, celery, fennel, and cilantro.

Shade gardens are a common place to find golden Alexander. In the wild they are common in moist rich woodlands, bottomland forests, mesic upland forests, upland prairies, glades, savannas, banks of streams, rivers, and spring, ledges, tops of bluffs, fens, but also along roadsides. Moist rich soil is best but they are very resilient and can survive harsh conditions. In ideal conditions their 2 foot tall and wide dome of foliage is green all summer long even in drought.

They bloom yellow in spring April–June. Seeds ripen in mid summer when the seeds turn brown and easily shatter from the stalk. They and are easy to collect to share with friends. Collected seeds need to be stored in the fridge in moist soil for a minimum of two months or directly sown outside over the winter. Seeds not collected or eaten by birds are highly likely to germinate nearby. Populations of golden Alexander can spread quickly and fill in a new garden. Golden Alexander is a good choice for woodland restoration after invasive removal because of it’s prolific spread by seed and hardy nature.

The flat-topped flower clusters are visited by many bees, flies, butterflies, and other insects. Zizia is the host plant for the black swallowtail butterfly, papilo polyxenes, and for the specialist mining bee, Andrena ziziae. The golden Alexander mining bee is a tiny native bee that digs out a burrow in the soil. Look for pencil size holes in bare soil near the Zizia plant to find these fuzzy native bees provisioning their nests.

The Black Swallowtail is a large black butterfly with yellow, blue, and red markings and swallow tails. They only lay their eggs on members of the carrot family of which golden Alexander is our native representative. Females can lay 400 eggs but only about 4 of them will survive predation. Young caterpillars are black with orange spots and bumpy. Older caterpillars are black and yellow with green stripes. In Missouri black swallow tails have two generations per year in April-June and in late summer. They overwinter as a chrysalis attached to a stem. Bringing the chrysalis inside may cause it to emerge early before there is any nectar available to eat.

Golden Alexander is a great addition to any shade garden. If it becomes too aggressive, it is easy to rip out. Control it’s spread by collecting the seeds and spreading them in the back alley. I love having this plant in my yard for the beautiful flowers that attract so many pollinators and the dancing swallowtail butterflies that grow on it. It is a great plant for a beginner garden or a neglected corner.