Geranium 'Rozanne' ('Gerwat')
Geraniums are versatile perennials that flower for several months through early summer and are at their best in July. One outstanding cultivar is Geranium 'Rozanne', easy to grow with gives masses of mauve flowers which emerge through the vigorous and lush foliage.
It looks at its best grown among shrubs and taller perennials where its lax habit can be used to full advantage and at RHS Garden Hyde Hall we use it in several mixed plantings such as the Island Beds in the Hilltop Garden to create this fantastic effect.
- Common name
- Height & spread
- 60cm (24in) x 40cm (16in)
- Herbaceous perennial
- Fertile, well-drained soil
- Full sun or partial shade
- Fully hardy
Cranesbills or Geranium comprise a genus of around 300 species of annuals, biennials and herbaceous, semi-evergreen, sometimes tuberous perennials. They are sometimes confused with the genus Pelargonium which is commonly, though mistakenly, known as geranium.
Cranesbills are found in all except very wet habitats in temperate regions. They are generally long-lived and undemanding plants. Compact perennials, to about 15cm tall, are good for a rock garden; trailing, spreading or mat-forming plants are effective as ground cover in a woodland or wild garden. Taller, clump-forming species and hybrids are suitable for a border or among shrubs.
The leaves, usually rounded or five-pointed, are palmately lobed with the divisions often further lobed and toothed; they frequently have interesting mark, textures, colours or scent. Flowers are white, pink, purple or blue, usually saucer-shaped, sometimes flat or with petals reflexed and often petals contrastingly veined.
Geranium 'Rozanne' ('Gerwat')
Geranium 'Rozanne' (‘Gerwat’) is a fast-growing herbaceous perennial. Among the geraniums, Rozanne is a taller, clump-forming hybrid.
Its leaves form mounds of slightly marbled, deep green foliage above which appear loose cymes of large (up to 5cm across) saucer-shaped, violet-blue flowers with pale whitish centres and red veins radiating out into the five petals. The flowering period is June to at least September.
Geranium ‘Gerwat’ is the registered cultivar name. It is thought to be a hybrid of Geranium himalayense and Geranium wallichianum ‘Buxton’s Variety’.
- Perfect for underplanting roses or filling a few gaps in the front of a border, coping well in full sun or partial shade. Most soils tolerated unless waterlogged.
- Water freely in the growing season. This plant is fast-growing and will benefit from a late summer chop to tidy up its habit and encourage production of fresh foliage and extended flowering. Cut back to one third of height with sharp shears or secateurs.
- Plants may be damaged by vine weevil and sawfly larvae, slugs and snails. In dry conditions powdery mildew may be a problem.
- Sow seed in containers outdoors as soon as ripe or in spring.
- Lift and divide large colonies in spring.
The RHS Floral Trials Subcommittee awarded Geranium Rozanne (‘Gerwat’) an Award of Garden Merit with the description:
'Low, semi-prostrate, 30x100cm wide. Foliage dark green, lightly blotched yellow green. Flower top 4cm, violet, grading to pale pink on basal half of petal. Lightly veined translucent red. Anthers dark purplish brown. Flowering prolifically for a prolonged period, from June to the first frosts.'