By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties

As tree planting season winds down and the weather warms, we are already starting to see buds popping on spring’s earliest bloomers. Soon the spring explosion will be in full force. It won’t be long before the hillsides are brilliant yellow – and not with daffodils.

Photo: Eric Coombs, Oregon Dept. of Agriculture, bugwood.org
Photo: Eric Coombs, Oregon Dept. of Agriculture, bugwood.org

Colorful and abundant as it is, Scotch broom is one of the more serious forest weeds that we have to contend with. The Oregon Department of Agriculture has estimated the economic impact of Scotch broom on Oregon forestland at $47 million annually – that figure includes lost forest productivity and control costs. Continue reading

By Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension – Benton, Linn & Polk Counties

Even a wall of blackberries can be tackled
Even a wall of blackberries can be tackled

In recent entries in this series on the basics of herbicide use in weed control, I have reviewed how some foliar herbicides work, and the relationship between the plant’s physiology and the herbicides’ behavior. Now I want to illustrate how that that information translates to what gets done in the woods, looking at controlling blackberries, a frequent target of foliar herbicides.

Blackberries are a problem because they are widely dispersed by birds and start readily from seed and once established, rapidly spread vegetatively by tip rooting, quickly forming daunting patches seemingly too tall and wide to tackle. We’ve all seen these conditions in old pastures, riparian areas and struggling plantations. Continue reading

By Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension – Benton, Linn & Polk Counties

In previous installments of this series on the basics of herbicide use in weed control, I distinguished between foliar and soil active herbicides, describing foliar herbicides as those applied to the leaves or stems of plants to be absorbed and carried throughout the plant to affect control. In the previous post I began discussing foliar herbicides in more detail with an overview of glyphosate.

In this entry I will look at a group of herbicides called “growth regulators” that include some important foliar herbicides and popular weed and brush killers commonly used in forestry, agriculture and habitat restoration. Continue reading

By Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension – Benton, Linn & Polk Counties

In my previous installment of this series on the basics of herbicide use in weed control, I distinguished between foliar and soil active herbicides. In this post I begin discussing foliar herbicides in more detail. Note: The attention given to herbicides in this series does not indicate an advocacy for their use but an acknowledgement that using herbicides presents some unique risks, and that landowners and managers need to know enough about them to make informed decisions on their use.

Foliar herbicides are applied to the leaves or stems of plants to be absorbed and carried throughout the plant to affect control. They are common and widely used to control annual and perennial herbs and also woody shrubs. Continue reading

By Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension – Benton, Linn & Polk Counties

Weed control is a top of mind topic now for many landowners. Following this spring’s strong log market, a lot of folks will be reforesting a harvest unit. Others may be planting a field of Christmas trees, or a swath of trees and shrubs as a restoration project to improve habitat conditions. And it seems everyone is struggling to control one invasive weed or another on the property.

While a number of approaches and strategies (including mowing, pulling and mulching) can and are used in managing weeds, many people will use herbicides as at least part of their approach. This is no surprise given their demonstrated effectiveness and efficiency. But not all users are well-versed in vegetation management, or the science behind it, so some review of herbicides seems to be in order. The attention given to herbicides in this and later articles does not indicate an advocacy for their use but an acknowledgement that using herbicides presents some unique risks, and that landowners and managers need to know enough about them to make informed decisions on their use.

Now, it is important to realize that one need not be a crop scientist to use herbicides. The label gives instructions that ensure the safe and allowable use of an herbicide, so the label needs to be read and followed. But responsible and effective use of herbicides requires some additional understanding about herbicides and how they work, as well as knowledge about the life cycle and other characteristics of both crop and target plant species they will be used with. Let’s begin talking about some basics. Continue reading