Managing Aphids in the Landscape

Aphids are not something you want to find in your garden, and yet we all do find them at some point, unless you have created a toxic haze of chemicals around you and your garden-then you would not even have issues with neighbors. Realistically, though, in a well balanced, healthy landscape, there will be some aphids and other pests. 

Aphids on a rose flower bud

Aphids do most of their damage with piercing-sucking mouthparts, that suck out plant juices and often wither or distort leaves, flowers, and buds. They can be found on nearly every species of plant, but are most commonly seen in our landscapes on milkweeds, tall sedums, daylilies, roses, and annual flowers. The oleander aphids seen on milkweeds are the most common species, but there are others. Reducing their populations can be tricky.

Oleander aphids on milkweed, being attacked by lacewing larvae

I am sure most of you would love to go out and see your landscape completely pest free, with perfect leaves and flowers. However, this is unrealistic. Without caterpillars, there would be no butterflies or moths. Also, caterpillars and other pest insects make up a large portion of the diets of many bird species through the summer months. 

Oleander aphids on purple-leaf plum

Aphids can be controlled a number of ways. If they become a problem on your roses, milkweeds, annuals, sedums, or daylilies, the best control is likely to be a chemical. While this may not seem to be the best way, these plants do most of their work in a short period of time and if the aphid population is not significantly reduced, you may not see the value of these plants. Therefore, chemical treatment. I recommend fertilome Rose & Flower Food with Systemic Insecticide.

The author recommends fertilome products

I know what you are thinking, a systemic insecticide? Yes, systemic. It has been shown through various university studies that a systemic applied to the soil is less harmful to bees and other pollinators than chemical sprays. Also, it has been proved that systemic chemicals are not ingested by leaf feeding caterpillars such as Monarchs. The systemic chemical is taken up by the plant and spread through the xylem and phloem of the plant and not into the leaf surfaces. Thus, only piercing-sucking insects such as aphids, lacebugs, and mealybugs are affected. 

In cases where aphids are attacking flower buds, it may be necessary to apply a foliar spray. When spraying insecticides on flowers or flower buds, try to do it early in the morning, before most bees and other pollinators are active. I recommend a mix or 2 parts water to 1 part dish soap and applied directly to flower buds or plants, where aphids are present. 

These ninebark aphids can be removed from the plant by pruning

Other aphids may be attacking trees or shrubs. If you can see them and they are a problem, such as the above ninebark aphids, I would recommend just cutting these off and dropping into a bucket of soapy water. The oil in the soap suffocates insects of all types. On trees, let nature take its course; the trees can stand some damage and here is where natural predators lick lady beetles, lacewings, and some wasps come for dinner. The whole aphid population may not be decimated, but it is usually kept under control.


Happy planting!

Leave a Reply

Your email address will not be published. Required fields are marked *