Aphids: Vampires of the Plant World

What Are Aphids?

Aphids are small, soft bodied insects that feed on plant sap.  These sap suckers can be green, brown, black, or even pink, but regardless of their color they are all after the same thing. I know you are thinking to yourself, how much damage could these little guys do? Large colonies of aphids sucking sap from the rose bush cells will cause blooms to become deformed and they will not open properly. Unfortunately these vampires of the plant world are not deterred by garlic wreaths or wooden stakes, so let's explore what the home rose gardener should do to protect their blooms.

Use a Slow Release Fertilizer

Aphids are heavy nitrogen feeders.  This turns well fertilized plants, such as roses, into a well-stocked buffet line for sap sucking insects. In order to fertilize rose bushes without providing a large meal for aphids, we need to feed the bush with a slow release fertilizer.  Quick release fertilizers will push a large amount of nitrogen into the bush quickly making it a tasty treat for aphids.

Invite Beneficial Insects to the Party

Ladybugs, Green Lacewings, and Pirate Bugs will all enjoy feasting on your Aphid population, but they tend to be fashionably late to the party. They show up after the Aphid population has already exploded in the garden. In order to encourage the beneficial insects to show up earlier, we need to create a welcoming environment before the Aphids take over. Here is a quick list of companion plants that will encourage these beneficial insects to to make your garden a home.

Ladybugs Common Yarrow Ajuga Marigold Dill

Green Lacewings Fern Leaf Yarrow Dandelion Golden Marguerite Coriander

Pirate Bugs Corn Soybeans Grapes Alfalfa

Water Hose Riot Control

I know this seems counterproductive for rose care, but spraying the colonies of Aphids off the rose bush with a garden hose is a simple cost effective way to get rid of Aphids.  You get the same effect with a spray bottle set to the stream function to blast those buggers off the bush. Make sure you keep up with your fungicide application if you go this route and it is also a good idea to do this in the morning so the rose bushes have the rest of the day to dry.

Last Resort Insecticidal Soap

Aphids have soft bodies that have openings called spiracles that they use for respiration.  Insecticidal soaps work by covering these openings and suffocating the Aphids.  It only takes an hour to work, but it might take multiple applications to get the problem under control as it only works when the soap makes contact with the Aphid.  The residue left by the insecticidal soap is non-toxic so it is safe for local wildlife.

Helpful Hints

Thistle, Mustard Plant, and Milkweed will only encourage Aphids to populate a garden. Keeping a rose garden clear of these weeds will help control the Aphid population as well as other problem insects.