Buckthorn Problem

We have been fighting buckthorn for almost ten years and continue to work on it. All of our large buckthorn have been eliminated long ago, and what we have now are new plants that have come up from the seed bank. Many of these are single stems or groups of a few stems. They can grow to four to five feet high in a summer. All a controlled burn will do is top-kill these plants, and next summer they are back again from the root stock.

I am trying a new approach to eliminate this "forest" of buckthorn stems. In mid-August Chris mowed several large patches with our Stihl brush cutter, using a sharp saw blade. He hauled off the cut stems so that we could follow what happened. Within a month we had a "nice" crop of new stems, such as shown in the photo below. I did some counts and found about 75 separate buckthorn shoots in a square meter quadrat. The photo at the right shows what happened to a single cut stem. The first bud below the cut stem sprouted and has formed a shoot with a terminal bud and four leaf clusters. What to do?

Herbicide is the answer, and the herbicide I chose is fosamine (Krenite), a bud inhibitor that is very effective against woody plants. A 3% foliar spray was used. According to the literature, fosamine is taken up by the leaves and transported to the terminal buds, where it inhibits new bud growth next spring. Tests I ran last year showed that this approach was quite effective, and fosamine was much more effective that glyphosate.

Another advantage of fosamine is that it has only a short lifetime in the soil, generally about a week, so that growth of desirable plants next year should not be affected. In addition to whatever native plants are already present, later this fall I will be overseeding the area extensively with savanna grasses and forbs.

This is still an experimental approach, but I have marked plots, including controls, and if my results repeat those of last year, I plan next year to apply this technique to all our buckthorn-problem areas.

This sort of restoration research is maddingly slow, but essential!

Stiff Gentian

Stiff gentian (Gentianella quinquefolia), a late-flowering prairie-savanna species, has just come into full bloom. It is a handsome plant that can be found nestled down among the asters and goldenrods. According to Cochrane and Iltis, this is a winter annual (biennial) that requires a calcareous soil and thrives in an ecologically open microhabitat without too much competition. The seeds of winter annuals germinate in the fall and form small plants which overwinter in the vegetative state. The following year they grow to maturity, flower, set seed, and die.

At Pleasant Valley Conservancy our indigenous stiff gentian plants were found primarily among our roadside prairie remnant (County Highway F). Seed collected there has been planted in other parts of the Conservancy and we now find it in quite a few areas, both prairie and savanna.

Because new stiff gentian plants arise only from seed, we are always careful when collecting seed to take no more than half. The remaining seeds are allowed to sift onto the ground and become the forerunners of next year's plants.

Collecting Lily Seeds

We have two lilies in our area, turk's cap lily (Lilium michiganense) and wood or prairie lily (Lilium philadelphicum). Turk's cap lily is a wet-mesic species which occasionally is found along the edges of woods or in grassy openings. Although I have seen wood lilies in wooded areas, it is more commonly an inhabitant of dry prairies, where it can exhibit rather spectacular displays. Although both of these lilies have gorgeous flowers their seed pods are very inconspicuous.

The photos here are from turk's cap lily, but wood lily pods are not much different. The seeds are arranged inside the pod like a stack of pennies. You don't need many pods to get a substantial number of seeds, which is a good thing, because pods are hard to find.

Growing these lilies is an excercise in patience. The first year seedling is usually a single leaf, which dies back by midsummer. The second year you may get two leaves, and the third year three or four. Most of the growth for the first few years is in the root, which eventually forms a bulb. It took us seven years to get wood lily flowers from seeds planted in the Pocket Prairie.

Collecting Silphium Seeds

Today Kathie, Susan, and I spent most of the day collecting compass plant (Silphium laciniatum) and rosin weed (S. integrifolium) seeds. We also found time to collect naked sunflower (Helianthus occidentalis), purple prairie clover (Dalium purpurea), and pale purple coneflower (Echinacea purpurea). Lots of species are ready to collect now!

Compass plant and rosin weed are great plants to have in a prairie, but they present a challenge in seed collecting. The challenge is that goldfinches love the seeds and are able to clean out a seed head quickly. It's a race to see who gets there first, the goldfinches or us.

One approach is to collect the seeds just "before" they are ready, when they are harder for the goldfinches to get at. At this time you collect not just the flower head, but a 2-3 foot length of stem as well. During the drying process, this stem (so they argument runs) provides nutrients for the final stages of seed maturation. Since the goldfinches can't get to the drying rack, one gets a lot better yield of seed.

I've been unsuccessful in finding any research paper that confirms the procedure described in the previous paragraph. If anyone is aware of hard data on this topic, I'd love to hear of it. Email me at tdbrock at charter dot net.

Bad News on the Poke Milkweed Seeds

Kathie opened up one of the poke milkweed pods I collected a few days ago. Bad news. The seeds look like seeds but they are all flat. That means no embryo inside. Of course, that is only one pod, but still, it's not encouraging.

It's hard to know what caused these abortive seeds. The weather had been really favorable this summer, so it can't be the weather. One possibility is that they were self-pollinated rather than cross-pollinated. Research on another species of milkweed (A. incarnata) has shown that good pod formation and seed set only occurs if there is cross pollination. This means you need another plant nearby. Actually, all of the poke milkweed pods I collected came from about 10 plants that were all within 100 yards of each other. Certainly not so far away that bees, the usual pollinators, could not travel from one plant to another.

Let's hope some of the pods have good seeds!

Poke Milkweed Seeds

Today we were collecting seeds, and one of my jobs was to collect from poke milkweed (Asclepias exaltata). This is a relatively uncommon milkweed that is fairly common in our shadier savannas. Before it flowers it can sometimes be confused with purple milkweed, but the flowers are completely different. Also, it is more efficient at making pods. Today I found 20-25 pods from 10 different populations. I also left a pod or two on each plant for further seeding of nearby areas.

We collect milkweed pods when they are brown and somewhat flexible, and when they are perhaps showing a crack along the suture. If a pod is already open, we leave it for posterity. Collecting when the pods are still closed makes cleaning easier. Each milkweed seed has a long tail of fluff which unfolds when the pod is open. Once the fluff has unfolded, getting it off the seed is difficult without getting fluff all over.

Cleaning seeds that are still encased in pods requires patience. Open the pod along the suture and hold with one hand the mass of brown seeds that are concentrated at one end. Use the other hand to strip the fluff from the seeds and let it fly away. (This job must be done outside!) When you finish, you will have a handful of clean seeds; all the fluff will be off in the wind. A single pod will usually yield 15-25 seeds.

I won't add poke milkweed seeds to the general savanna seed mixes we make this fall. Rather, they will be hand-planted in suitable areas where they are currently absent. I find a suitable bare area among the trees, kick away the leaves, and drop in a few seeds which I then press down with my shoe.

The germination efficiency of milkweed seeds is usually fairly high, around 50-75% (with cold-stratified seeds).

A nice photo of poke milkweed can be seen on the species checklist.

Collecting Flowering Spurge seeds

Flowering spurge (Euphorbia corollata) is a nice native plant common to dry prairies. It is fairly sensitive to grazing and hence is usually absent from formerly grazed prairie remnants.

Flowering spurge can be readily reintroduced from seed, but seed collecting is a little tricky. This is because as soon as the seeds ripen the three-lobed seed pods pop, shooting the seeds out into the environment. Success seems to depend on finding the plant at exactly the right stage. Too soon and the seeds aren't ripe. Too late and the seeds are gone.

Today we used a new technique recently developed by Madison Audubon at Goose Pond. Instead of collecting just the seed head, a one-foot length of the whole flowering stalk is cut, selecting stems that are turning brown but with seed heads still somewhat green. The cut stems are immediately placed head down in a bucket and later transferred to a screened drying rack. (The screen makes sure that any popped seeds remain in the rack.) Keeping the flowering stalk ensures that there is sufficient nutrient for the final stages of the seed ripening process. After all the seeds have been released, the stalks are carefully removed and the seeds collected from the bottom of the rack. Success!

 

Birthday (80 years old)

Today (Sunday) I turned 80. Kathie and friends put on a super birthday party at Pleasant Valley. Unfortunately it rained, so we moved the whole party into the barn (which we had cleaned well in anticipation of such a problem). Since the barn floor is concrete, it worked out very well. My son Brian (guitar) and his colleague Tim (drums) did excellent live music (although we skipped the barn dancing). Daughter Emily flew in from Palo Alto. Probably because we were all crowded in the barn, conversation was animated and there was a great festive spirit.

We promised tours of the prairie, and despite the rain we kept our promise. Everything look fresh and green, and people who hadn't visited Pleasant Valley before were impressed. Probably 100 people attended the party.

The photo shows the six birthday cakes that Kathie made. Yummm! At the end of the party, only a few slices were left.

Seed Collecting Today

Today Kathie and I ran a volunteer group collecting prairie seeds at Black Earth Rettenmund Prairie, a State Natural Area for which we are the stewards. Despite unsettled weather and a bit of early-morning rain we had five intrepid volunteers participate.

Black Earth Rettenmund Prairie is a very fine dry-mesic prairie remnant, one of the best in southern Wisconsin. The seeds we collect there are used in our restoration of parts of the preserve that still need help. (What prairie doesn't still need help?)

We collected mainly side oats grama, prairie cinquefoil, prairie dropseed, and lead plant. Compass plant and a few other species were not quite ready, but will be ready in a week or so. For seed collecting, it is important for us to monitor sites frequently to make sure that we "catch" the seeds at the right stage. The seed collecting dates given on another page are very useful but only approximate.

Mowing Ridge Prairie

Kathie and I both took turns at mowing the Ridge Prairie, probably for its final mowing of 2006. (See photo below of an earlier mowing.) This is the end of its first growing season. Although it was primarily a weed patch, there were a few "good" species in flower, including black-eyed Susan, ox-eye sunflower, and great blue lobelia. The latter was a surprise, since this is generally considered a species of wet-mesic habitats. It certainly was not in the seed mix we planted last December. It may have developed because of the good moisture we have had this summer. It probably won't persist in the Ridge Prairie.

In addition to plants in flower, there are lots of things in the vegetative state that are probably good species, although identifications are always questionable at this stage.

Field Trip

Our annual Labor Day field trip was held from 1-4 PM. In the morning the weather had been rainy and unsettled, but by the time of the trip the sky had brightened a bit. There were twelve people plus Kathie and I, a nice sized group. The prairies and savannas were in good shape. The red-headed woodpeckers were very active in the savannas and the group was able to see three separate birds.

As usual, Kathie provided bags with which participants could collect side oats grama and bottle brush grass along the trail.

Larger photo of the group

Mowing

Restoration work involves a lot of mowing, mostly to get rid of annual weeds before they set seed, but sometimes to get rid of biennials that set seed only in their second year. Mowing is a major activity in planting new prairies, because the weeds grow so much faster than the prairie plants. The first growing season of a newly planted prairie requires two or three complete mowings. Even the second growing season, an early summer mowing is often desirable.

For most of our mowing we use our Kubota BX 2200 tractor. This has an underdeck mower (intended for lawns) which also works pretty well for small ag fields. The top photo shows Kathie doing the first mowing of the newly planted Ridge Prairie in late May 2006.

Today, we finished our second mowing of the Sandhill Crane Wet Prairie. This field, in its first growing season, was planted on the snow in early December 2005. It's a long narrow field next to our wetland, and is a little rough because we took out lots of large trees. Although the contractor did an excellent job of cutting the trunks close to the ground, the terrain is still fairly rough.

For the Crane Prairie we used a Land Pride rotary mower that works off the three-point hitch of the tractor (the bottom photo shows the rig when we were using it at Black Earth Rettenmund State Natural Area). The Kubota is a small tractor that needs a small mower, but this means it is a lot more maneuverable. Paul Michler, who did this mowing, is skilled at avoiding "good" plants (of which we have quite a few even in this first growing season).

We manage fairly well with the Kubota because most of our fields are small. With large ag field restorations, such as the 40 acre plots that Madison Audubon Society plants, you need a real agricultural mower. The few times that we have needed such a rig, we have hired a local farmer. Fortunately, we are in an ag area where farmers are often readily available.