As we enter the winter months at the nursery you may not be thinking about your weeds or herbicide but it is actually a great time to get your preemergent applied. Currently, in the field we have tractors applying Marengo on liners and small trees that wont be dug next spring and for things that are a saleable size we are applying a mixture of Sureguard and Pendulum Aquacap. We chose to use the fall for this application because the rain and snow will water in the herbicide and create a nice barrier for the first few months of the busy spring season. This should hold the weeds off through June to help save labor in spring. The reason we are not using Marengo on saleable size plants is for cost savings since we know equipment will be in those areas breaking the soil and herbicide barrier. So applying a second round of a cheaper herbicide after the dig is a better option.
On our containerized material being stored in hoop houses we do a fall application of Sureguard BEFORE we cover houses. This is important to do before you cover and water it in because it will off gas under plastic and can cause residual damage. This application is designed to prevent cold weather weeds like bittercress from germinating under the plastic through the winter and early spring. Make sure to check labels on all herbicide to prevent accidental damage to non-tolerent species. The last thing we do to the hoop houses is put out bait blocks for rodents. These bait blocks aren’t a set it and forget it all winter situation though. Its still important to walk your houses at least a few times a week to look for rodent damage or evidence of chewing on the bait blocks.
Also one final spray we do in the field is applying an anti transpirant on our in ground evergreen material. This prevents the winter desiccation that will occur in the cold windy months here in Chicagoland. This desiccation happens because the ground is frozen and the roots cant supply water to the needles or branchlets as they dry out in the wind. We typically use a 10% rate on our Transfilm for this application and see good results. We don’t spray containerized material in our hoop houses because they are out of the wind and we don’t usually see damage but if that is a problem you have seen you could also apply to containerized material as well.