Controlling Pests on Flowers, Roses & Ornamental Plants

Keep the good insects in your lawn and landscape while controlling the damaging ones.

Your landscaping looks beautiful; it's planted with a variety of trees, shrubs, roses, and flowers. But to many bugs, it may also look like lunch. Almost every plant in your landscape can be attacked by one or more insect pest, and being able to identify and control these pests is an important part of properly caring for your landscape.

Learn About Potential Pests

Different plants attract different pests and, in some cases, different species of the same pest. Boxwoods are attractive to spider mites; crape myrtles are preferred by a specific species of aphid; slugs love hostas; and aphids, thrips, Japanese beetles, and spider mites are drawn to roses. Here are some of the most common pests that can be found feasting on your flowers, roses, and ornamentals.

Aphids

Many different species of aphids can be found on ornamental plants. They range in color from green, yellow, black, and pink to red. Aphids can attack most plants in your landscape, but many species have an affinity for soft, succulent plants like flowers and roses. They cause damage to your plants by sucking plant sap and sometimes spreading plant diseases. Because they reproduce rapidly, a few aphids can quickly explode into a major infestation.

Whiteflies

If you’ve ever planted tropical hibiscus in the summer, you’ve probably encountered whiteflies. The two seem to go hand-in-hand. Whiteflies hang out on the undersides of plant leaves, but clouds of white adults will fly around infested plants when they’re disturbed. Like aphids, the suck plant sap and reproduce rapidly and can quickly become an infestation.

Scale

Different species of scale can be found on camellias, hollies, magnolias, euonymus, and many other ornamentals. Scale are unusual because, unlike other insects, they spend most of their lives underneath a hardened or soft waxy covering with their mouthparts imbedded in a plant. Bad infestations can result in weak, distorted growth and death of branches or the entire plant.

Thrips

These tiny pests are most problematic on flowering plants. They cause damage by feeding on leaves and flowers reducing their aesthetic value in your landscape. Thrips feed by puncturing plant cells and sucking up plant juices. Feeding is concentrated on young, actively growing tissue, so leaves and flowers are often crinkled or distorted. Thrips are also known to transmit certain plant viruses.

Spider Mites

Known to attack over 150 different plants, spider mites are actually arachnids, a closely related group to insects. Adults are so tiny they are barely visible to the naked eye. They can vary in color from red to yellow or green, and the two-spotted spider mite is one of the most common species. They cause damage by sucking the fluid from plant cells resulting in a light-colored stippling appearance on leaves which can look bleached or bronzed during heavy infestations. When there are a large number of spider mites present, they can create webbing at the tops of plants.

Slugs & Snails

Like spider mites, slugs and snails are also not insects; they are mollusks and closely related to oysters. They are most active at night, spend the day hiding in your landscape, and thrive in areas of your garden with constant moisture. Damage caused by slugs and snails are long, narrow holes left in leaves. Slugs and snails will also leave behind shiny, dried slime trails.

Japanese Beetles

This garden pest will feast on more than 400 different species of plants including trees, shrubs, herbaceous perennials, and annual flowers and vegetables. Japanese beetles will eat the foliage and blossoms leaving behind skeletonized plants, and the severity of the damage is dependent on the number of beetles present. They are particularly drawn to large, light-colored flowers (white and yellow roses are some of their favorite plants to target.)

How to Kill Pests on Your Ornamental Plants

When it comes to killing pests attacking your flowers, roses, trees, and shrubs, you have several options available. To kill pests like aphids, Japanese beetles, and whiteflies on your roses, useOrtho® Insect Killer Rose & Flower Ready-To-Usewhich keeps killing listed insects for up to 4 months. If you have a problem with spider mites, useOrtho® Insect, Mite & Disease 3-in-1 Ready-To-Use; it controls listed insects, spider mites, as well as wide range of fungal diseases. For larger jobs, useOrtho® Insect Killer Tree & Shrub Concentrate. It kills leaf-feeding beetles, spider mites, thrips, and other listed insects attacking your trees and shrubs. To kill slugs and snails destroying your hostas useOrtho® Bug-Geta® Snail & Slug Killer2. Always check the label before applying any product to find the insects controlled and the plants it can be applied to.

Prevent Future Problems

There are several steps you can take to help reduce future pest problems in your landscape.

Avoid planting varieties that are prone to pest problems. For example, the “indica” types of crape myrtle are more likely to develop aphid problems that other varieties. If you have a problem with Japanese beetle, plant ornamentals they are less likely to attack (boxwood, flowering dogwood, red and silver maples, lilac, juniper, and rhododendron are good examples.)

Keep your plants healthy and vigorous so they can better defend themselves from attack. Stressed plants are more likely to be attacked by pests. Properly care for your plants by providing the right amount of fertilizer (not too little or too much), watering correctly, providing plants with enough space to grow, and making sure they receive adequate sunlight. Spider mites, for example, are more likely to attack plants during periods of hot, dry weather and are less likely to attack plants that are kept well-watered during these periods.
Thoroughly inspect any new plant for insect problems before purchasing it and planting it in your landscape.
Stop small problems from becoming big problems by selectively pruning to remove infested branches or hand-picking off pests. It is best to do this during the cool, early morning hours when pests are less active. You can also spray plants with a forceful stream of water to wash pests like spider mites, scale, and aphids off stems and branches.
Keep the landscape clean by removing leaf litter, excess mulch, piles of stone, debris, and weeds where pests, like slugs and snails, prefer to hide.
Be careful to keep the good guys in your garden while controlling the bad ones. Not all insects are bad. Ladybugs, praying mantises, minute pirate bugs, and parasitic wasps all attack pests that can damage your plants. Aphids are attacked by ladybugs; parasitic wasps prey on aphids and scale; and black lady beetles, lacewing larvae, minute pirate bugs, and predatory mites attack spider mites. And don't forget about the bees that help pollinate many of your flowering plants.