Are they a benefit for your rose garden or a nuisance? The answer is yes. Although some bugs can cause significant damage to our favorite roses others actually help to control the “bad bugs”.
Probably the most common insect pest is the aphid. These little bugs usually start to appear in early spring, feeding on tender new growth. Although you may only see a few aphids initially more will quickly appear if not eliminated. Aphids range in color from green (making them difficult to see on foliage) to a rusty brown. Left unchecked they will suck the moisture from your plants causing considerable damage in your garden. You may find that aphids prefer a particular rose or area of your garden.
If you notice ants on your roses take a close look for aphids. These two creatures maintain a friendly relationship. The ants feed off a sweet substance secreted by the aphids. In exchange ants offer the aphids protection from predators.
Leafcutter bees favor roses for both their leaves and sometimes using canes for nesting. These bees do not form colonies like honeybees instead they make singular nests in rotted wood or pithy plants (like roses).
You may not notice the actual bees in your garden but you will surely recognize their presence. Leafcutter bees, as their name indicates, cut small circular holes along the edges of certain leaves. Unfortunately for our gardens they fancy rose leaves.
The good news is that although their calling card may be a somewhat unsightly Swiss cheese effect to a few leaves, the damage usually stops here. Occasionally these bees may take up residence in a large, freshly cut cane. These bees are non-aggressive and have a mild sting (less than that of a common honey bee).
Thrips are small flying insects that, like aphids, prey on new growth and tender buds. Although they may infest any rose they seem to prefer roses with light colored flowers. The females lay eggs in the soft tissue of the flower bud. Once these hatch they begin to drain the moisture from the plant causing brown spots on the edges of the buds and sometimes preventing the flower from opening.
Spider mites are another minute threat to roses. These tiny arachnids prefer the underside of leaves. A telltale sign of spider mites are small webs located either on the bottom of leaves or between leafs and stems. During the dormant season these pests can be found around the base of your roses on dead leaves and weeds. This makes clean-up during the winter important.
Chemical sprays are also effective in combating most bug pests. Make sure your read and follow directions carefully when using chemical treatments. Some fertilizers may also contain pesticides to help control many common rose threats.
Organic treatments are also available if you prefer to avoid chemicals. One of the best organic treatments is to offset the bad bugs by introducing good bugs. Ladybugs and praying mantis love to feed on aphids. Both of these are available at nurseries and garden centers. You can even buy ladybug houses and concoctions that attract the beetles to your garden. They are likely to stay as long as you have a food source (more aphids) on your plants.
Leafcutter bees are valuable pollinators and generally cause minor damage. The only effective means of preventing them from damaging your roses is to cover them with some type of material. This is rarely worth the effort considering the relatively minor amount of damage they cause. Simply remove unsightly leaves.
Prevention and early detection of these common rose pests will help you keep a healthy garden of roses for you to enjoy all season long. Remember to check your roses often and look for the warning signs. And also remember, not all bug are bad.