Noxious Species of the Month


With the start of spring upon us, we should start to think about weed control on our properties. It seems this is the time of year most people think about controlling their weedy species. There are multiple species that you can target early in the spring, but the first species people should be concerned with is Whitetop (Hoary Cress). Along with its early growth, it is one of earliest species to set seed, so waiting until summer to employ control methods is not an option. Get to know some key identification characteristics and some control measures, so if this species is found on your property, you will be ready to put an early season stop to this nasty weed.

Whitetop has many unique characteristics that you will find helpful when trying to spot this problem invader. It is a perennial that grows up to two feet tall, usually forming dense patches if left uncontrolled. It has alternate, lance shaped leaves that become lobed as the plant matures. The plant has a greenish grey appearance and is completely hairless. Flowers are small and white having four petals. The flowers are dense and form an umbel (umbrella) appearance on the top of the plant. The roots are fibrous and extensive, and the plant will use the root system to put out new shoots that will lead to new individual above ground plants.

This species can also produce a new plant from an individual piece of the root system. Also, keep in mind the time of year as this species will be flowering in April and May before most other plants begin to flower. There is one species, Field Pennycress, that has similar traits and grows early in the year. When looking at the two species, the differentiating characteristic is how their leaves attach to the stem. Whitetop leaves clasp around the stem, and Field Pennycress leaves have a stem (petiole) attaching to the main stem. These identification traits should help you pick out this problem species, before it takes a stronghold on your property.

Control usually comes down to the three main types of mechanisms: Mechanical, Chemical, and Biological. Most mechanical mechanism are not the answer for this species, because, as stated above, it will reproduce from root parts making mechanical control difficult, but there has been some success with repeated deep tillage (at least six inches). Biological control is not an option currently as no insect releases have taken place yet, but there are some promising insect species that are in the final testing phases now. Herbicide control is usually your easiest and most realistic option. Herbicides will differ depending on what type of site (Range, Crop, ROW) the treatment is taking place on, but usually some type of ALS inhibitor will be used. For example, in a range situation, Escort (Metsulfuron Methyl) would be used at a rate around one ounce. Remember, when trying to control any species implementing multiple mechanisms, when applicable, usually leads to your best control.

With the mercury on the rise, now is the time to be out looking for this noxious weed. If you happen to find this species, do not wait to implement a control strategy, because it will be setting its seed before you know it, and you will have missed your opportunity for control. Hopefully this information will help you to better identify this culprit, and put a stop to it before it becomes a perennial problem on your property. Remember, if you have any question or concerns, please stop by our office or give us a call.