Tom's Blog

Friday, May 4, 2012

Zizia aptera and Zizia aurea

Golden Alexanders (Zizia aurea; C value of 7) is now in full bloom all over southern Wisconsin, providing excellent prairie and savanna color. This is a reliable plant for restorations, as it does well and requires little care.
Two species of golden Alexanders growing side by side in the Barn Prairie.
When we started restoration at Pleasant Valley Conservancy we had large amounts of this plant on the County F roadcut, and that was the source of the seed we used for all subsequent restoration work. It still does well along County F, although the populations there flower two weeks later than those in the prairies. This is reasonable, since County F, being north-facing, provides cool habitats where everything is delayed. (The vegetation along County F is more typical of savanna than prairie.)

A closely related species is Zizia aptera (heart-leafed golden Alexanders; C value of 9). This is a lot less common in Wisconsin, although I know of one remnant prairie in Dane County where this is the only Zizia species present. We have very little of Z. aptera, and what we do have was brought in as seed, but it seems to slowly becoming established. The photo at the top shows the two species growing side-by-side.We also have a few Z. aptera in the ridge-top savanna.

When we were first creating the Barn Prairie we had a lot of trouble with smooth brome and arranged to have the co-op spray it with glyphosate early in the season. The idea was that cool-season grasses (such as smooth brome) would already be up and would be killed, but warm-season grasses and prairie forbs would still be underground and would be unaffected. This mostly worked, but getting the spray timing  right is a little tricky. The year we sprayed, tiny shoots of golden Alexanders were already starting to come up, and some of them were set back. In fact, that year we essentially had no golden Alexanders at all. Fortunately, they recovered next year and are now doing very well, as the photo shows.


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