Goldenrod Galls

What began as a simple search for interesting props for my upcoming Sketching Nature workshop, led to a great illustration of how much there is to discover if we only look more closely. Among the things I collected were the dried stems of goldenrod, many of which had classic round goldenrod galls. But I soon discovered other deformities that I hadn’t noticed before: stunted stems with tufts of leaves at the tops, and elliptical-shaped growths on stems.

It turns out that more than 50 species of insects—mostly flies, midges, and wasps– lay their eggs on goldenrod stems. When the larvae hatch, they borrow into the stem, causing the plant to form a protective chamber around the growing grub. When the larvae transforms into an adult, it emerges from its hideaway and flies off. Sometimes woodpeckers drill into the gall for a meal, in which case, you’ll find a small hole in the gall. For the most part, the insects don’t harm the plant; though in the case of the bunch gall, they do stunt the growth of the stem, causing leaves to sprout at the top and curtailing the growth of flowers.

So, there you have it…a bit of natural history for your day and an invitation to go out and see what you can discover.

Tips & Techniques– Keep it simple! I wanted this page to illustrate how much you can do with a few simple things on a page and a limited amount of time. I drew everything directly in pen and shaded only the darkest areas. I added watercolor in three loose layers, using combinations of yellow ochre, burnt sienna, and ultramarine blue. A bit of spatter near the dried flowers and the “goldenrod galls” text were my finishing touches.