Prized for their immunity to ailments and compact growing habit, “Knockout” shrub rose varieties can also endure temperatures which other rosebushes cannot. These flowers come in many horticultural variants, blooming in various shapes and sizes as well as several different colours. In fact, many “Knockout” roses may produce different colored blooms within precisely the same variety.
Red
Although red is the traditional color of the romantic stem curtain given on Valentine’s Day, this color is also utilised from the smaller, sturdier “Knockout” roses used in landscaping and gardening. This color attracts both butterflies and hummingbirds, adding even more color to the garden. The “Knockout” rose (Rosa x “radrazz”), which lives in U.S. Department of Agriculture hardiness zones 5 through 10, blooms in red and features an open, flat, cup-shaped flower. The “Double Knockout” rose (Rosa x “Radtko”), which also thrives in USDA zones 5 through 10, produces a similar flower shape with twice as many petals.
Yellow
“Knockout” roses also come in yellow, and this color is often used to contrast with red and pink roses. The vibrant yellow is also appealing to butterflies and birds and is very attractive to bees. Furthermore, the bright yellow coloring may attract moths and other night pollinators, because they are drawn to flowers which stand out from surrounding leaves from moonlight. Yellow “Knockout” forms include the “Sunny Knockout” rose (Rosa x “Radsunny”), which grows in USDA zones 5 through 10 and produces profuse explosions of bright yellow flowers that produce a strong scent.
Pink
Some “Knockout” roses feature blossoms that are hot pink (almost red), while some are an actual pink. The “Blushing Knockout” rose (Rosa x “Radyod”), which grows in USDA zones 5 through 9, features a teacup-shaped bloom that is bright pink set against dark green leaves. The “Pink Knockout” rose (Rosa x “Radcon”), which thrives in USDA zones 4 through 9, is a deeper-colored pink and features upturned pink petals that create a prominent teacup form.
Bi-Colored
The “Rainbow Knockout” rose (Rosa x “Radcor”) grows in USDA zones 5 through 10 and features two colours within precisely the same flower. The outside of the flat-form flower features a bright pink colour, but the petals turn bright yellow near the middle.