Do you have Desert Broom growing on your property? You can help protect our beautiful desert setting and our Natural Area Open Space (NAOS) areas by learning to identify this invader. October through January, mature Desert Broom is in bloom; the ﬂowers are pale cream or bright white (never bright yellow). An established plant has stiff stems and leaves (like broom straws). Homeowners are responsible for plants on their private property. This invasive weed is number one on Scottsdale’s invasive weed list and it is on Desert Mountain’s Prohibited Plant List. Desert Broom is aggressive and grows quickly to ten feet high or more. It gets started in disturbed areas or at the base of an established plant. In Desert Mountain it often gets started near fences or other structures and in retention basins. Desert Broom burns ﬁercely and is a signiﬁcant threat to nearby structures.
Mistletoe is a parasitic ﬂowering plant that can grow on many Palo Verde, Mesquite and Acacia trees. It grows into a dense mass of branched stems on the infected tree. About 80% of the infected trees we see around Desert Mountain are Mistletoe, while the rest are Witches Broom infestations. Mistletoe infections are mainly spread by birds that feed on the Mistletoe berries and tap into the tree’s system for food and water. Once an infection has occurred, the root system of the Mistletoe grows within the tree branch. Left untouched, it will attain a size that will greatly weaken the tree and can kill major branches or even the entire tree. The control of Mistletoe is difficult in large areas such as the golf courses and NAOS. The most effective way to control Mistletoe and prevent its spread is to prune out infected branches as soon as they appear. It is recommended to prune the tree branch below the point where the Mistletoe is attached. Detection and control can best be done in the fall and winter when Mistletoe is easily seen.
Witches Broom is growth response to a mite infestation that causes a deformity in the natural structure of the tree, often found in Palo Verde trees. To identify Witches Broom, look for a dense mass of shoots growing from a single point resembling a broom or a bird’s nest. Witches Broom is not parasitic and has its own photosynthesis process to receive its nutrients. Control of Witches Broom is best accomplished by properly pruning the infected branches to remove the brooms. Because the disease is caused by insects, further treatment may be needed with the application of a systemic insecticide/miticide by a licensed pest control operator.
Stinknet - previously known as Globe Chamomile
At Desert Mountain we strive to educate residents and visitors about the Sonoran Desert we live in. This education includes the identification and the impact of non-native and invasive plants. In addition to the over population of native Desert Broom (Baccharis sarothroides) and non-native Fountain grass (Pennisetum setaceum), we have begun to see in our community a newly introduced and highly invasive plant called Stinknet (Oncosiphon piluliferum). A native of South Africa, it is soon to be classified as an Arizona Noxious Weed. If you see this aromatic plant, pull it up! Preferably, before it goes to seed through March. The Desert Mountain Community, along with DLC, has plans to address this plant along the parkway and other common areas.
Why are they bad?
Non-native invasive plants out-compete native plants for resources like water and soil nutrients needed to grow. In addition, they significantly increase the fire potential.
Call to action!
Your assistance is needed to gain control over these plants. When you see Stinknet, please pull it up. Ask your landscaper to remove Desert Broom from your private property. Contact the Desert Mountain Community office with questions.
Brochure about Stinknet from AZNPS Conservation in partnership with Maricopa County Parks and Recreation Department, The Native Plant Society, and Arizona Department of Agriculture. Additional information is available from the Sonoran Desert Cooperative.