Tom's Blog

Monday, July 13, 2009

New Jersey tea and butterfly milkweed

Lots of things are in bloom now, but two plants that are especially attractive are New Jersey tea and butterfly milkweed.

New Jersey tea (Ceanothus americana) is found both in prairies and savannas, but at Pleasant Valley Conservancy it is mainly a savanna species. When we began restoration, the only place we had any significant number of plants was along shaded areas of County Highway F, where they increased extensively after we started brush control. There were also a few plants in an open savanna area among bur oaks.

We collected seeds and planted them widely throughout the preserve. A few years later we started seeing them in flower, and now I am finding them all over. The photo above is of a new flowering plant I just found in Unit 19C, right by our service road.

A "trick" with New Jersey tea is that the seeds don't germinate well unless they are given a brief exposure to boiling water. This is somewhat counterintuitive (don't plants die when they are heated?), but the heat treatment must be very brief. Bring water to boil in a small sauce pan and throw in the seeds, swirl around until all seeds are wetted, and then quickly pour the mix into a food strainer. Immediately douse the seeds in cold water. They should be planted the same day they are treated.

Butterfly milkweed (Asclepias tuberosa) is one of the most attractive prairie plants, and is now in full bloom in southern Wisconsin. This is mainly a prairie species and is rarely found in savannas. It likes dry to dry mesic sites. The best populations I have seen are at Black Earth Rettenmund Prairie, where they are visible even from the highway. Kathie and I have been managing this site for about six years and this year there are more butterfly milkweed plants than ever. The very favorable weather must be partly responsible, although I'd like to believe our extensive restoration work is also a factor.

This is an easy plant to grow in natural areas, although it takes a few years when planted from seed. It can also be easily raised in pots and then transplanted to a site. Some plants may flower the next year after transplanting. According to Woodson, individual plants will live many years.

The photo here shows two plants growing profusely in a forbs garden that we set up at Pleasant Valley Conservancy. We also have a very nice patch in our home garden.

In the City of Middleton, the median strip of University Avenue has lots of butterfly milkweed, which is flowering well at the moment.


Blogger Emily said...

Dad, can you explain in more detail why the New Jersey Tea needs boiling water to germinate? This doesnt seem to make sense evolutionarily. What happens with the seed in a natural setting (with no boiling water around)? Also, do you know what part of the seed is affected by the heat?

July 13, 2009 at 8:25 AM  

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