A true geranium to brighten the garden

Low-maintenance and low-growing ‘Rozanne’ will steal your heart

Say the word “geranium” and most gardeners are going to think of the windowbox plants that add nearly year-round color to a sunny spot. Those plants, botanically Pelargoniums, are closely related to the genus Geranium. Theselow-growing, spreading and equally colorful perennials are such a garden staple that it is easy to take them for granted. They seem too pretty to be used as a ground cover, and yet their low-growing habit doesn’t qualify them for use as an upright ornamental. Don’t let that “in-between” status deter you from adding one or more to your garden. One look at the “queen” of the geraniums, G. ‘Rozanne,’ will win you over in a hurry.

‘Rozanne’ (USPP #12175) has one of the largest and showiest flowers in the geranium genus. Starting in summer, plants produce an abundance of bluish-purple flowers that are 2 to 3 inches wide. They also feature contrasting white centers and radiating wine-color veins. By late summer, the 4- to 10-inch tall plants are smothered in a sea of purple, attracting the attention of bees and butterflies. Scalloped and lightly veined mid-green leaves provide the perfect backdrop for this summer and fall blooming display.

Geraniums are versatile plants. Use them as an attractive ground cover in any sunny bed, be that with other annuals or perennials or as a way to fill in an untended slope. Once established, geraniums are surprisingly tough and resilient. They combine well with nearly every landscaped bed and provide a soothing carpet of green when not in bloom. They’re also perfect for spilling over a low rock wall or out of a hanging basket.

Geranium ‘Rozanne’ can take the heat. Where other perennials might wilt, ‘Rozanne’ keeps on ticking. As fall progresses, the leaves may acquire a reddish tint, adding to the plant’s charm. If cold enough to go dormant, plants will return in the spring.

Geranium ‘Rozanne’ is but one of a number of Geranium varieties that are referred to as “blue.” Consider the equally lovely ‘Johnson’s Blue,’ which is similar enough to ‘Rozanne’ to be confused for it. It is also on the lower side, to 12 inches, and features the same large bluish-lavender flowers. Then there’s G. ‘Orion,’ a taller (24 to 30 inches), slightly more purple cousin to ‘Rozanne.’ Though the flowers are a bit smaller (1.5 inches wide) it nonetheless puts on a spectacular blooming show in summer and fall.

Earl Nickel is an Oakland nurseryman and freelance writer. Email: food@sfchronicle.com