8 Hardy geraniums with blue flowers

Geranium 'Rozanne'

Few hardy geraniums feature bicoloured flowers and are easy to grow. However, this is the case with the now very famous Geranium ‘Rozanne’. From late spring until autumn, a profusion of bicoloured blue flowers with a white centre appears, measuring approximately 5 cm in diameter. Additionally, it produces large, apple-green leaves slightly maculate with dark green in the centre. The habit of this geranium is creeping, spreading to form semi-bushy carpets of 20 to 30 cm in height and 50 cm in width.

This geranium shares the same characteristics as Geranium wallichianum: a remarkable blue flowering marked with white at the centre. However, unlike this species, which only thrives in very well-drained soils, ‘Rozanne’ tolerates heavy soils and excess water in winter, although it prefers light, cool, and rich soils. It grows in full sun, but tolerates shade very well; in fact, when grown in partial shade, its flowers are more intense in colour. Hardy, it withstands cold, even damp, down to -16°C.

Please note: this perennial geranium is so fabulous that it was voted “plant of the century” at the Chelsea Flower Show 2013.

Geranium 'Azur Rush'

Hardy Geranium ‘Azure Rush’ is somewhat “the little brother” of ‘Rozanne’. Indeed, this hardy geranium is a mutation of the latter. ‘Azure Rush’ shares the same qualities, but it is more compact, with slightly purple-tinged green foliage, an even denser habit, and absolutely remarkable vigour. Its azure blue flowering is abundant, generous, from June until the first frosts. This groundcover perennial has a bushy, rounded, and compact habit of about 40 to 50 cm in height and 40 to 50 cm in diameter.

Hardy Geranium ‘Azure Rush’ is quite hardy. It enjoys full sun or partial shade and a more or less well-drained soil. It can be grown in well-tended gardens or slightly wild ones, but also in pots or hanging baskets.

Geranium 'Johnson's Blue'

Popular since its introduction in 1950, the Hardy Geranium ‘Johnson’s Blue’ remains a reliable choice. It is the result of a cross-breeding between Geranium himalayense and Geranium pratense. This exceptional groundcover, forming clumps 40 cm high, blooms for a long time (from May to July) and abundantly with beautiful cup-shaped flowers in a light blue tinged with violet and a white centre. The foliage is equally impressive! It is deciduous and takes on red and orange hues in autumn. Each leaf is deeply cut and lobed.

It is a very hardy geranium that copes well with summer heat. The perennial ‘Johnson’s Blue’ thrives in full sun or partial shade. Easy to grow, it should be planted in well-drained, rather cool soil.

Please note: the Hardy Geranium ‘Johnson’s Blue’ is a hybrid cross between two species. Therefore, it is sterile and will not self-seed.

Geranium 'Brookside'

The hardy geranium ‘Brookside’ closely resembles the geranium ‘Johnson’s blue’. The difference is that ‘Brookside’ is more floriferous, its lovely light blue flowers with a white centre are also larger, and its habit is taller yet just as dense. It is a hybrid resulting from the cross-breeding of the meadow geranium and the highly floriferous Geranium clarkei ‘Kashmir Purple’. This geranium blooms abundantly from late spring, throughout summer, and into September, with a pause in August during the heat. The plant forms a spreading clump, making it an ideal groundcover, and the foliage takes on lovely warm hues in autumn.

The hardy geranium ‘Brookside’ prefers a sunny position, but it tolerates partial shade. Plant it in fertile, well-drained soil that remains cool, whether calcareous, acidic, or clayey.

Geranium 'Rosemoor'

Among the truly sturdy hardy geraniums, Geranium x magnificum ‘Rosemoor’ holds a prominent place. It stands out as a giant in the world of hardy geraniums, with a dome reaching 60 cm in height and 50 cm in diameter, and its growth is very rapid. It is a robust and vigorous plant that forms an opulent and regular clump, and it also displays beautiful autumn hues. But let’s talk about the flowering: this perennial disappears in summer (from June to July) under brilliant, blue-mauve flowers with purple veins, grouped in compact cymes. As it is a hybrid, this geranium will not self-seed.

The hardy geranium magnificum ‘Rosemoor’ prefers sunlight, but never scorching; it also thrives in partial shade. It will do well in ordinary, cool, humus-bearing, not too acidic, well-drained soil. This geranium tolerates difficult conditions, including occasional droughts, but it will be at its best in the sun and in soil that remains cool.

Geranium 'Sabani Blue'

The Hardy Geranium ‘Sabani Blue’ is a stunning new variety filled with qualities! It is a hybrid (thus sterile!) resulting from the cross-breeding of Geranium ibericum and Geranium libani. This groundcover perennial has a bushy tufted habit of 50 cm in height with a spread that will extend over time, and the growth is rapid. It blooms from May for at least two months with a possible resurgence in September. The flowers of ‘Sabani Blue’ appear in dense clusters. They are violet-blue with a white centre. Each petal is marked with fine purple veins, and the dark anthers stand out from the centre. The semi-evergreen foliage is a beautiful bluish-green.

The geranium ‘Sabani Blue’ is robust and can thrive in all types of soil, even the most challenging. However, it prefers well-drained soils that remain moist. This hardy geranium can be grown in full sun or partial shade.

Geranium 'Dark Reiter'

The Geranium pratense ‘Dark Reiter’ is a variety derived from the meadow geranium. The contrast is striking between the very dark purple tinged with brown of its deeply lobed foliage, the dark red of its stems, and finally the lavender blue of its flowers punctuated with black stamens. This dark foliage makes the blue appear very intense, especially in partial shade. The ‘Dark Reiter’ variety has a semi-spreading tufted habit (25 cm in height and 30 cm in diameter) and its growth is rapid. Flowering occurs between June and July.

In the wild, Geranium pratense thrives in woods and annually mown slopes. This perennial prefers a sunny position and fresh, rich, rather calcareous soil. Please note, the meadow geranium is susceptible to powdery mildew during dry spells.

Nota bene: the Geranium pratense or meadow geranium (type species) is a species that grows naturally in Europe (mainly in the North-East of France). Now in decline, it was once found in the countryside, especially in mown meadows, along roadsides, and in wet meadows.

Geranium 'Blue Cloud'

The hardy geranium ‘Blue Cloud’ is a charming little invader that loves to weave its way between other plants. This award-winning recent variety from the RHS (Royal Horticultural Society) features a spreading or climbing habit (particularly leaning on surrounding plants): 40 to 70 cm in height, with a spread of at least 90 cm. Flowering occurs from May to July-August. The flowers, a very soft blue-grey, have 5 narrow petals and measure 4 cm in diameter. The foliage is deeply incised, deciduous, and appears very early in spring, with each leaf that darkens in summer.