For milkweed grown as monarch habitat, our recommendation is to avoid neem oil. Milkweed is food for monarch caterpillars. A product used to suppress insects can also expose the insects you are trying to support.
Inspect before you intervene
Look at stems and both sides of the leaves. Check for monarch eggs, caterpillars and beneficial insects as well as aphids. Orange or yellow oleander aphids often gather on milkweed, but their presence does not automatically mean the plant needs treatment.
Allow helpful insects time to work
Lady beetles, lacewings and other natural enemies can feed on aphids. Tolerating some feeding damage is part of maintaining a host plant. A butterfly garden is not expected to have perfect, untouched foliage.
If aphid numbers become a problem
Inspect carefully before any physical removal. Where you can avoid eggs, caterpillars and predators, gently remove a small aphid cluster by hand or use a targeted water rinse. A strong spray can dislodge desirable insects too, so do not wash the whole plant indiscriminately.
Insecticidal soap and other sprays are not automatically safe substitutes. Avoid routine pesticide applications on monarch host plants. If a plant is declining, ask your local Extension office to help determine whether aphids, moisture problems or another issue is responsible.
Build a useful butterfly garden
Choose milkweed species appropriate to your region and site. Combine host plants with suitable flowering plants for adult butterflies, and allow room for plants to grow. Regional suitability matters more than a blanket claim that every milkweed is right for every garden.
