African Rue Management | Southeast New Mexico

What Is African Rue?

African Rue in flower like those found around Carlsbad and Southeast New Mexico.
African Rue In Flower - NPS [Public domain]

African Rue is an invasive weed species that has become well established in Southeast New Mexico. It has very heavy pressure near Carlsbad and spreads through most of the southeast corner of New Mexico as well as many parts of the country.

Horizon Pest Control provides professional weed control services for the management of African Rue as well as reclamation of areas around Carlsbad in Southeast New Mexico that are populated by the invasive weed.

Description / Identification

The African rue, Peganum harmala, is a bright green succulent perennial. It has a woody base and root system that grows deep into the ground which is a major factor to its survival and makes it very difficult to control.

  • This noxious invasive weed is a fast growing perennial with many branches that can grow taller than two feet and a bit larger than four feet wide.
  • The roots of African Rue can grow over 20 feet deep as well as twenty feet laterally which makes it very drought tolerant and able to survive our Southeast New Mexico climate.
  • The flowers are white and have five petals that bloom from spring to early fall.
  • African Rue has tough leathery pods that contain an average of 50 or so dark brown seeds.
  • The stems are bright green and smooth and the leaves alternate and are smooth like the stems.

Favorite Growing Conditions

African Rue does well in most soil types including the harsh alkaline soil of Southeast New Mexico. It does especially well in moist soils.

It is most commonly found growing in barren and open areas in need of weed control such as oilfield and industrial sites, parking lots, roadsides, open fields, etc.. This drought tolerant weed survives just fine on packed caliche roads and pads.


African Rue is listed as a noxious weed in Arizona, California, Colorado, New Mexico, Nevada and Oregon. This invasive weed is dangerous and toxic. The entire plant is toxic. However, the most toxic parts are the seeds and seed pods. The pods and seeds are desirable to grazing livestock and it only takes about 0.15% of an animal’s body weight to be deadly. Peganum harmala has four different alkaloids that make it deadly to humans and livestock.

Africa Rue's toxicity goes beyond being lethal to humans and livestock. It's also toxic to other plants which makes it easy for it to outcompete the native plants in Southeast New Mexico. It germinates earlier in the spring than other vegetation and creates chemicals that make it difficult for other plants to survive.

How To Kill African Rue

Effective control treatment options are limited. Because of the plant's deep root system, mowing, burning, and tilling do not kill the weed and it generally grows back. Tilling and grubbing can produce more plants that can grow from stem and root pieces.

As well, and one of the main factors in managing African Rue is to treat it and remove it before it goes to seed. It can be necessary at times to remove individual plants that are close to seeding. This can be done by covering the plant with a plastic bag and cutting it at the stalk.

So, what are the treatment options? How to kill African Rue?

  • Broadcast Foliar Spray Treatment
  • Broadcast Soil Spray Treatment
  • Individual Plant Treatment

Broadcast Foliar Spray Treatment

A broadcast foliar spray treatment of African Rue is ideal when there are a large number of plants and no threat of harming any desirable native vegetation from the spray. Both selective and non-selective weed control can be used depending on surrounding vegetation and the chance of over spray and drift of the weed killer.

The same as other weeds treated with foliar applications, environmental conditions, physical conditions, and timing need to be right for best results.

African Rue is best foliar treated when it is in a vegetive growth stage and preferably when it is young and tender. However, the plant can go through more than one vegetive growth stage in a season. The plant will die back in drought and heat but will spring back to growth when the rains come. These are the best times to do a foliar spray application.

Another important factor in getting the best results with most weeds in foliar spraying is humidity. When humidity is high, plant leaf surfaces are open and will take in more herbicide. When weeds are in drought, they close up and don't respire to conserve moisture.

Broadcast Soil Spray Treatment

Again, the same as with foliar application, surrounding vegetation needs to be considered before a soil application as they are generally non-selective soil sterilants that inhibit all vegetation.

Most generally, broadcast soil treatments are combined with a foliar treatment to address any weeds that may already be growing. This type of treatment is ideal for keeping large areas such as oil pads and industrial sites vegetation free. Soil treatments keep large open areas that are prone to seeding of African Rue from being able to support growth.

Timing is also important with soil treatments. While it's not always possible, soil treatments are most effective when applied when there is rain in the forecast. Precipitation helps to get the herbicide into the root zone where it can work.

Individual Plant Treatment

Treating individual plants is the best option when there are few plants and or there is desirable vegetation around. There are a few different ways to go about it.

  • Foliar spray application of individual plants works well when nearby plants won't be affected.
  • Whole plant removal requires cutting the African Rue plant at the base and then treating the root stem with herbicide. If the plants are close to or have already seeded, a bag should be secured over the plant before it is cut.

Measures To Complete Management

  • Early detection of African rue germination, and especially before going to seed, is very important to slow down the spread of this plant. African Rue is an invasive weed and once it has become established, it is difficult to get rid of without affecting the surrounding native plant habitat.
  • Mechanical and manual methods of control are inefficient. Spraying herbicide is most often the best method of control. However, even with spray applications, it can take years to bring the weeds down to acceptable numbers. In areas with a lot of weeds, it's often necessary to use a broad spray foliar and ground treatment to get an area to acceptable numbers.
  • Continued monitoring after the initial treatment is necessary. If monitored closely, spot spraying and individual plant treatment should only be necessary.
  • If possible, over seed with native plant varieties. Healthy and thick native plant varieties will help slow the spread of African Rue.

African Rue Control Services

Again, African Rue is an aggressive invasive weed that can get out of control quickly if not managed properly. Early attention and constant monitoring are necessary for areas prone to African Rue.

The technicians at Horizon Pest And Weed Control Service in Carlsbad are trained in the management of African Rue that grows in Southeast New Mexico. They know what to look for and how to spray treat without harming the sensitive surrounding environment.

Whether its consulting, individual plant treatment, ground spray or foliar spray, Horizon Weed And Pest Control Services in Carlsbad provides weed control services for the management of African Rue in Southeast New Mexico. Give us a call for service today at 575-725-9331 for a free consultation and appointment.