It looks like ladybugs, perhaps immature ones, possibly eating aphids.  I would do nothing as it looks like they have everything under control.  If they bother you, rinse them off with a garden hose.  I think now I would be more concerned with your flooding as roses aren't aquatic plants! 

Seriously, if you continue to see them, send a close-up and I can try to identify the species.

An Extension Master Gardener who is much better at bug identification than I will every be said that these are a type of scale similar to http://2.bp.blogspot.com/-Qk_LBMxgpic/UbfDoECW8-I/AAAAAAAAIt8/mzHhpOjO2nA/s1600/Oak+lecanium+scale+i... .  Scale are milky/juicy inside like you say your insects are.   

Here is something from Clemson, S.C.'s Extension Department on scale:

Rose Scale

Adult scale insects have an unusual appearance. They are generally small and immobile, with no visible legs. They secrete a waxy covering, making some appear white and cottony while others appear like white, yellow, brown or black crusty bumps. The waxy covering or "scale" protects adult scale insects from many insecticides. Their immature forms, called crawlers, are susceptible, however.
Adult rose scale on a rose cane
U.S. National Collection of Scale Insects Photographs Archive, USDA ARS, www.insectimages.orgSeveral species of scale are pests of roses, but rose scale (Aulacaspis rosae) is one of the most serious. Female rose scales are round, gray to white and about 1/16 inch long. Males are elongate, white and much smaller than females. These insects overwinter as eggs under the waxy covering of the mother.Rose scales are usually found on rose canes where they feed on sap with their piercing-sucking mouthparts. With a heavy infestation, rose scale can cause cane decline or twig dieback.

Control: Various natural enemies, including ladybird beetles (ladybugs) and parasitic wasps, usually keep scale insects under control. With light infestations, scale can be scraped off by hand and destroyed. Pruning out and destroying heavily infested canes is helpful. Horticultural oils (also called supreme, superior or summer oils) work well to control armored scales, such as the rose scale, by penetrating their waxy covers and smothering them. Horticultural oils applied at higher rates of 3% to 4% during the dormant season (i.e., to a rose bush that has lost its leaves) will penetrate the thick waxy covers of the overwintering adults. Applications at lower rates of 1% to 2% can be used during the spring to target the crawlers (immatures) and the newly settled scales with thin waxy covers. It is best to spray when temperatures are between 40 and 85 degrees.Monitor the crawler emergence in the spring with sticky cards, double faced tape wrapped around a branch, or by putting an infested shoot into a baggie and watching for crawler movement. The presence of crawlers can sometimes be determined by sharply tapping an infested twig on a piece of white paper. Crawlers are very small and will appear as moving specks of dust.Avoid using insecticides as much as possible as they will often kill the naturally occurring enemies of scale. When insecticides are necessary, they should be applied only when the crawler stage is present. The following insecticidal sprays are effective against crawlers only: acephate, bifenthrin, cyfluthrin, esfenvalerate, lambda cyhalothrin, malathion, or permethrin. Soil drenches of imidacloprid do not control these armored scales, but soil granular applications of dinotefuran may give some control.