Milkweed is a nice addition to garden landscapes because it’s a beautiful perennial, and more importantly, it supports the monarch population that has been in danger. Milkweed plants are very easy to grow but oleander aphids (milkweed aphids) are a common problem. If the infestations are large enough they will gradually suck the life out of the plants. Plus, it’s possible that monarchs will avoid laying eggs on majorly infested milkweed leaves.
There are some very simple and natural methods that can be used to get aphid infestations under control. When I consider how to deal with the attacks on my plants, I assess the amount of aphids first, and I look for beneficial insects nearby. Ladybugs and lacewings are among the many aphid predators that can help remove them. If there are not hundreds of thousands of aphids covering the milkweed, I figure it’s best to leave them there. They are a food source for the natural controlling predators which also help the other plants in my garden.
When I see the oleander aphids multiply and completely cover the milkweed in my garden, that’s when I know I need to do something or the plants will die.
Before using any of the following natural methods, it’s important to look for monarch eggs or caterpillars on the plants first. If there are eggs on the leaves, carefully work around them. If there are caterpillars, you can temporarily move them to another milkweed plant until you’re done removing the aphids.
Removing Aphids by Hand: This is perhaps the most obvious method of removing aphids, but I’ve found it to be the most tedious. You simply rub the aphids off of the stems and leaves of the plant using your fingers. Wear gloves if you don’t want squished aphids all over your hands!
Removal by Hose: I have tried this method on large infestations of aphids and it’s perhaps my least favorite method. Using the jet setting on your hose sprayer, you attempt to spray the aphids off of the plant. I’m always afraid of damaging the plants by hitting them with a strong stream of water, and the aphids seem to hang on for dear life every time.
Wash with Soap: Based on my experience, this method has been most effective in reducing large aphid infestations. The soap eats away at the waxy coating on the aphids’ bodies and they dry up.
- Add a tablespoon of liquid castile soap to 32 ounces of distilled water in a large bowl and mix well.
- Pour into a spray bottle.
- Spray the aphids on the stems and leaves of the plant, including the undersides of the leaves.
- After the aphids die, gently spray the plant with water to wash the soapy mixture away.
- It’s very important to note that only pure liquid castile soap without synthetic chemical additives should be used.
- To make sure the plant won’t be harmed by the spray, test it on a small area before spraying the entire thing.
- Spray during the early morning hours to prevent the leaves from burning in the hot sun.
- I feel better rinsing the plant with water afterwards so a soapy residue doesn’t form.
- It is best to use distilled water as opposed to tap water because the soap can react with components of tap water and form a residue that is tough to remove.
While removing aphids from my milkweed plants, I’m not overly obsessed about taking out each and every one. I don’t want to destroy the natural habitat of beneficial insects who love to feast on them!