Management of Natural Areas

Weeds in Winter


In October and November, the seeds germinate and get off to a fast start for a few weeks, but the temperature drops, the days get shorter, and as a result, growth essentially comes to a halt. In the winter of 2011-2012, the cessation of growth was particularly apparent due to the lack of rain, but even that winter’s relatively warm weather did nothing to accelerate plant growth.

The same growth pattern occurs for the resprouting native perennials and weeds. They begin to grow with the fall rains, but stop by late November or early December.

If you were to go outside in January and look at the herbaceous plants, you would notice that the weeds and the natives were roughly the same size. At this stage, it can be hard to tell which grasses are natives and which are weeds. For this one period of the year, they look pretty much the same, and you need a practiced eye to tell them apart.

This doesn't last, of course. As spring nears, the weeds begin their season of rapid growth. They are extremely competitive, overtopping small native plants and suppressing them.

Eliminating Weeds and Favoring Natives

Weed control is the most important maintenance task of the year, and it is where where you can have the greatest impact to create long-term improvement in your native landscape. You provide the natives the best opportunity to grow and dominate the site by eliminating their competition.

Mid winter (January and February) is an excellent time to control weeds because they are small. The weeds relatively little foliage and are easy to isolate. If you use herbicide, you need very little to kill a seedling. If you use hand tools, one quick chop and you’re done.

However, people feel no urgency to control weeds in mid winter, because the weeds appear innocent. They are small and don’t call attention to themselves. In winter, all plants, native and weedy, look nice.


Weeds in Late Winter

By mid-February, weeds start to grow rapidly, generating dense, tall foliage. The broadleafs, such as mustard and radish, begin to bolt. Weed control becomes more labor intensive as it becomes necessary to use mowers and weed trimmers. The amount of herbicide goes up and the labor to chop out weeds increases as well.

Conditions change for small native plants as well. From October through January, they were in full sun, with little competition. By late February, they may become covered with weed foliage. If left under weed cover, they become suppressed and can die. If, however, weeds are controlled through the spring and the natives remain in full sun, they can grow and thrive, gradually dominating the site. As the natives compete more effectively against the weeds, they reduce the long-term maintenance cost.

If you already know that you need to control weeds in a given area, you will be much better off by getting ahead of the problem now. If you spray small mustard and hemlock in January and February, you won’t be dealing with large, tall weeds later. If you start mowing weedy grasses in winter, you won’t have thick masses of grass foliage in the spring. You will save money and receive improved results.

By starting weed control early, you provide your native plants the greatest benefit of the spring growing season. Instead of just removing overgrown weeds, you are managing your landscape and moving it forward.

Weed control is more than a chore. It's your best opportunity to make a meaningful improvement in your natural landscape. Take advantage of it.


Do you need assistance? That’s why we’re here. We have trained crews that the know the difference between the natives and the weeds. They know which plants to mow and spray, and which plants to leave. We can take care of your weed problems and enhance your natural landscapes....quickly and efficiently.

Please give us a call.

Dave Kaplow
Pacific OpenSpace, Inc.