October 15, 2009 at 7:50 a.m.
In those days milkweed was considered an enemy to farmers, especially if they were in the grain fields at harvest time. Farmers still may consider them as a troublesome weed, but now more gardeners are protecting them knowing that milkweed is the main diet for the monarch butterfly.
Another change is our attitude toward a shrub called buckthorn. Up until a few years ago you could buy certain kinds of buckthorn in plant nurseries, but not anymore. There are three main buckthorn species found growing in Minnesota. They are the dwarf alder, common or European buckthorn, and frangula, also known as glossy buckthorn. Common or European buckthorn is native to Europe and was brought to Minnesota as a hedging material in the mid 1800's. This species does well as it grows in the understory of large trees in our region. It also survives well in thickets, pastures, abandon fields, roadsides, rocky sites, or just about anyplace.
Along with this shrub being drought and shade tolerant, it spreads rapidly by birds feeding on its fruit. Mostly robins, cedar waxwings, and mice eat the berries, which causes laxative effects and spreads the seeds to other areas.
Common buckthorn grows to a height of 20 feet with a spreading irregular crown. The bark is medium to dark grey, smooth with a powdery surface and should not be confused with plum trees. The twigs have sub opposite buds and a notable spine at the tip.
In the late summer there are many berry clusters of small, black fruit, one-fourth inch in diameter with three to four seeds in each berry. A distinguishing characteristic of buckthorn is that the leaves stay dark green on the tree well into winter, after most trees and shrubs have shed their leaves.
The State Parks Resource Management has controlled buckthorn by using a fall cut between mid-August to October. They follow-up with a stump application of the herbicide of one part Roundup (41 percent glyphosate) with five parts water using a hand sprayer. Joan Chouinard, Master Gardener, has researched buckthorn and can be reached through the Chisago County Extension Office.
Another plant that has turned villain is Virginia creeper. This is another plant that up until a few years ago could be purchased at the local nursery. It is a vigorous vine that can climb up and over small plants as well as up the trunks of larger trees. It was used for climbing fences or buildings, but became so invasive that it took over everything.
I don't know where it came from, but we had Virginia creeper climbing the log house that is now at the Almelund Threshing Grounds. Even after the building was removed it continues to grow underground until it is now spreading through my asparagus patch and beyond.