How to Control Star Thistle
Yellow Star Thistle is an invasive plant. It is not native to the United States. The plant was accidentally introduced to the western states over a century ago. Now found in 41 states, the noxious plant crowds out native species and is toxic to horses. Star thistle grows quickly from 6 inches to 5 feet tall. As it matures, the yellow-flower weed loses its leaves and grows nasty spikes that puncture skin. As the plant spreads into backyard and city lots, it becomes a nuisance to children and pets. The plants can be poison to dogs and other animals. Star thistle is controlled in several ways. Does this Spark an idea?
Instructions
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CHEMICAL: The most effective control of star thistle is application of systemic herbicides. A broadleaf weed killer is effective if used while the plant is young and has its broad leaves. It can be easily applied with a hand or tank sprayer. Check the label of weed killers at garden centers and hardware stores. Those that kill dandelions will often control star thistle.
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MECHANICAL: Hand weeding is rarely effective as the thistle has a deep tap root that grows several feet into the soil. Mowing can help control star thistle during the flowering stage before the thistle goes to seed. If the plant has leaves below the mower's cutting level, it may continue producing flowers and seeds after mowing.
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GRAZING: Some livestock will graze on the thistle when it is young. Goats will graze on the thistle even after it develops flowers and spikes. This grazing reduces seed production and the spread of thistle.
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BIOLOGICAL: Some insects and fungus attack the thistle seedhead and can reduce seed production by 50 percent or more. Commercial companies often advertise weevil control for thistles. These weevils lay their eggs in the flowers. When the eggs hatch, the larvae eat the developing seed.
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Tips & Warnings
If you spot star thistle in your yard, the earlier you apply an herbicide to the growing weed, the more effective it will be.
If a pet may have eaten or chewed on star thistle, contact your veterinarian.
When children are gathering plants for play, be sure they are not playing with star thistle due to the sharp spikes.
Always wear gloves and eye protection when working around star thistle.
