As a homeowner, you are likely aware that a healthy lawn requires regular maintenance. Among the many maintenance routines that homeowners should perform on a regular basis is weed control. One such weed that can quickly take over lawns is purple deadnettle (Lamium purpureum), an invasive plant found throughout North America. This annual weed emerges in the fall and flowers before the mowing season, making it somewhat difficult for homeowners to get rid of.
While purple deadnettle can be difficult to control, it is quite easy to identify this weed in your lawn. As a member of the mint family, purple deadnettle features a square stem and small, tubular-shaped purple flowers. This plant has triangular leaves with small lobes and a purple-red color on the upper leaves.
Purple deadnettle is a winter annual, meaning it germinates in the fall and blooms in the spring. Once temperatures begin to rise in early summer, the purple deadnettle will die. Oftentimes, homeowners may not even realize their lawns have purple deadnettle until after it develops seeds in the spring.
Although purple deadnettle control can be a bit challenging, there are a couple of solutions for stopping its growth. In this guide, we’ll walk you through the process of controlling purple deadnettle through cultural and chemical methods.
Purple Deadnettle vs. Henbit
Because purple deadnettle and henbit are both members of the mint family, it’s no wonder why these two plants are often confused with each other. Both purple deadnettle and henbit are winter annuals, and they may even be found growing side by side. Their appearance has slight variations, however, making it possible to tell these two plants apart.
Unlike purple deadnettle’s triangular-shaped leaves, henbit has round leaves that are green in color. Their flowers are also different, with henbit having darker purple flowers than purple deadnettle.
Pictured above from left to right: Purple deadnettle and henbit.
Non-Chemical Control of Purple Deadnettle
There are two main techniques for removing purple deadnettle from lawns: cultural (non-chemical) control and chemical control. Both methods have their advantages and disadvantages for removing purple deadnettle from lawns. Generally, cultural control is best for lawns with a small number of weeds, while chemical control is recommended for lawns with large numbers of deadnettle plants.
The best way to control and prevent purple deadnettle is to grow a dense, healthy lawn. Because purple deadnettle generally grows in areas with thinning turf, taking the time to nurture your lawn can greatly aid in preventing deadnettle infestation. You may also prevent purple deadnettle by removing objects that shade your lawn and avoid overwatering your turf.
If purple deadnettle has already taken root in your lawn, an effective method for removing the weed is to pull it out by hand. It is best to remove the deadnettle before it drops its seeds in the spring. Once you remove the purple deadnettle, continue fertilizing, aerating and caring for your yard to prevent future growth of this weed.
Proper fertilization of the lawn can help it develop a healthy canopy that is thick enough to crowd out weeds. Here are some of our favorite fertilizers. You can learn more about them in Why Use Lawnifi Fertilizer?.
Chemical Control of Purple Deadnettle
Another method for controlling purple deadnettle is using pre-emergent or post-emergent herbicides. Chemical control is often the best approach if the deadnettle has spread throughout your entire lawn. While there are many herbicide options available, they will typically fall under one of the following categories: pre-emergent herbicides and post-emergent herbicides. A pre-emergent, as its name suggests, controls weeds before they germinate and appear in your lawn. Post-emergents, on the other hand, are products that control currently existing weeds. Pre-emergent herbicides are best for treating purple deadnettle during the fall, while post-emergent herbicides are best for weeds that have already germinated in the spring.
Pre-Emergent Control of Purple Deadnettle
One pre-emergent option that can be applied is Dimension by Dow AgroSciences (active ingredient: Dithiopyr). This product is mixed into a spray tank for easy application across a specific area or an entire lawn and can provide season long control of weeds. Prodiamine 65 WDG is another pre-emergent that comes in the form of water dispersible granules (WDG) while Crabgrass Control Plus 0-0-7 with 0.37% Prodiamine is a weed-and-feed product that also contains Prodiamine. Both can be applied with a broadcast or drop spreader. Pre-emergents should be applied in the spring and in the fall.
Crabgrass Control Plus 0-0-7 with 0.37% Prodiamine Herbicide$54.95
Prodiamine 65 WDG$119.95
Post-Emergent Control of Purple Deadnettle
A few post-emergent options are listed below. SpeedZone Broadleaf Herbicide includes 2,4-D, Dicamba and Mecroprop-P in its mixture, which is a great combination of active ingredients for broadleaf weeds such as purple deadnettle. SpeedZone Southern Herbicide also contains 2,4-D and Dicamba. Finally, Q4 Plus combines active ingredients 2,4-D, Dicamba, quinclorac and sulfentrazone to control dollarweed. Both Q4 Plus and SpeedZone Broadleaf Herbicide can be tank mixed before application.
It should be noted that the above three products should not be applied on St. Augustine or centipede lawns as both grass types are sensitive to 2,4-D and other active ingredients. If you have a St. Augustine or centipede lawn, Atrazine-based weed control product like Hi-Yield Atrazine is one of the best options.
Hi-Yield Atrazine Weed Killer$16.95 – $19.95
Purple deadnettle control can easily be accomplished by using one of these two techniques. Whether you opt for cultural control or chemical control, following these methods will effectively get rid of purple deadnettle to promote a healthy, flourishing lawn.