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How to grow Geraniums:
The hardy Geranium is a genus of over 300 species from
temperate regions of both hemispheres. They are invaluable for their pretty
flowers, attractive foliage, and their ability to cover the ground, a
contribution in the suppression of weeds in the border. They have a willingness
to flourish without any special attention, and what is more they are
disease-resistant which in my book makes them irreplaceable for most garden
situations. They get their common name of "Cranesbills" from the shape of the
seed heads after the petals have fallen. They are long-lived and easily
propagated, so from the purchase of just one plant; by division it is possible
to quickly increase the stock.
Some confusion exists between geraniums and pelargoniums also frequently
referred to as geraniums. The mix-up can be traced back to the eighteenth
century and though both are members of the same plant family, they are very
different. The pelargoniums or 'Annual Geraniums'; are in fact very unlike the
hardy "Cranesbill" for they are only half-hardy being frost tender plants with a
single flower stem holding a flower head made up of florets. It was Joannis
Borman, 1738/1739 who first proposed pelargoniums as a group separate from
Geraniums. Unlike the half-hardy Pelargoniums, Cranesbill flowers come in shades
that also occupy the blue-end of the spectrum spreading towards pinks but do not
produce any of the deep vivid reds as the Pelargoniums. Many begin to flower in
late spring/early summer and continue on until autumn.
Leaves of hardy geraniums are typically divided into leaflets arranged in a
palm-like fashion. They range from the thumbnail-sized brown leaves of G.
sessiliflorum 'Nigricans' to the rich mid-green dinner-plate-sized leaves of G.
maderense. You can find leaves with all sorts of veining, and blotching of white
to deepest maroon and purple. Even when not in flower, the intricately cut
foliage makes a handsome addition to the borders giving valuable texture and
interest, mixing well with other herbaceous plants.
Many are herbaceous perennials that die down in winter and flower again year
after year. They vary in growth from about 6" (15cm) to 4ft (120cm) tall
depending on variety. New and lovelier varieties appear on the market each year
and few gardens are complete without at least one of them.
GERANIUM PLANTING:
Geraniums grow well in well-drained soil in sun or shade, depending on the
species. Their position in the border will also depend on the growing height,
for some are low growing and can be placed at the front of the border while
others are better placed to the centre where they will be at their best. Some
less vigorous species are useful in rock gardens (e.g., Geranium cinereum
'Lawrence Flatman').
GERANIUM CULTIVATION:
Geraniums require well-drained, fertile, soil. All are low-allergen plants, and
most are drought tolerant. However they should not be allowed to dry out; in
very dry summers make sure that the plants are frequently watered. If you garden
in an area with hot, sunny conditions then most of the species will benefit from
a position where there is some dappled shade in the hottest part of the day.
However some do better in permanent shade such as G. Nodosum while G. Phaeum
requires deep shade. Cutting back old flowering stems keeps the plant tidy and
often encourages a further flush of flowers.
GERANIUM PROPAGATION:
Most hardy geraniums are easily propagated by division, which can be done either
spring or autumn. Root cuttings may also be used and should be taken after
flowering has finished. Many species are also easy to grow from seed and many
will come true as long as there are no other compatible species in the garden.
In most cases seed pods split from bottom to top into five sections and the
seeds are then shot some distance away or simply fall to the ground, depending
upon the species. G. Robertianum self-seed easily and spread quickly, therefore
wonderful grown in a wild garden situation.
Seed is collected when it is ripe which is easy to detect as the seedpod
undergoes a colour change from green to brown. This is a sign of ripeness but
there will be varying degrees of colour depending upon the species. Luckily most
species flower and set seed over a long period of time so there can be plenty of
opportunity in which to collect it. However germination of Geranium seeds can be
quite erratic, often taking a long time for seedlings to appear. Seeds may be
sown from early February to late June in good free draining seed compost just
covering the seed with compost or vermiculite. Make sure the compost is moist
but not wet. If you are planting into pots, push a couple of sticks (lollypop
sticks are ideal) into each pot and cover with a polythene bag. If you are
sowing into trays you can rig something similar to keep the polythene from
touching the seedlings. Maintain a temperature of 13-20C (55-68F). Germination
takes 21-60 days. The germination period will depend very much on the variety
being sown as will the temperature; some germinate better at a slightly higher
temperature. Even the sowing time may differ with variety; some can be sown
again in September to October. If you are starting your collection by seed,
details of propagation for each variety will be contained on the seed packet.
DOUBLE FLOWERING GERANIUMS:
G. himalayense 'Plenum' Double, purplish-pink flowers flushed-blue with darker
veins with fern-like, mid green leaves. This lovely pink Crane's Bill makes an
excellent, long-flowering groundcover plant for a cottage garden or herbaceous
border. After the main flush in early summer, it flowers intermittently until
early autumn. Copes well with full shade. H. 10in. (2.5cm).
GERANIUMS FOR ROCK GARDENS:
G. cinereum 'Ballerina' Deep pink summer flowers with dark-maroon veins and
centres and deeply lobed, grey-green leaves. This dwarf form of hardy geranium
is particularly suitable for a rock garden. As long as it is given good drainage
it will produce a mass of attractively veined pink flowers from late spring to
early summer. H. 4in. (10cm).
MAGENTA FLOWERS:
G. 'Ann Folkard' is a scrambling ground cover, which has saucer shaped, flowers
with rich dark centres and veining, flowers all summer long. H. 20in (50cm)
G. psilostemon A.G.M. This vigorous Armenian Cranesbill produces a mass of
shallowly-cup shaped, vivid magenta flowers with black centres and veins from
early to late summer. It quickly forms loose hummocks of deeply cut, mid green
leaves, which turn a fabulous shade of red in autumn. An excellent plant for the
middle of the border. H. 4ft. (120cm).
PALE PINK FLOWERS:
G. pratense 'Mrs Kendall Clark' Pearl-grey, saucer-shaped summer flowers, dusted
pale pink and finely cut mid-green leaves. This exquisite meadow Crane's Bill is
one of the tallest and most vigorous hardy geraniums. It self-seeds freely,
although the offspring are likely to vary. An elegant plant for the middle of
sunny border. H. 3ft. (90cm).
DEEP PINK FLOWERS:
G. psilostemon 'Fluorescent' Incredible fluorescent, shimmering pink flowers
with a jet black eye, create a carpet effect just above the foliage of this
impressive perennial. A robust and striking border plant. Flowers: Spring to
summer. H. 48in. (120cm). Position: Sun or Part Shade.
G. macrorrhizum 'Bevan's Variety' Clusters of dazzling, crimson-purple,
saucer-shaped, summer flowers and aromatic, light green leaves turning
orange-yellow in autumn. The deeply cut, scented, semi-evergreen foliage soon
spreads to form low hummocks. A reliable plant for a dry, shady spot. H. 20in.
(50cm).
BEST BLUE FLOWERS:
G. bohemicum 'Orcid Blue' Clusters of orchid-blue, saucer shaped flowers with
purple-violet veins and soft green, leaves. This stunning plant soon spreads to
form low hummocks of deeply cut foliage, valuable for suppressing weeds at the
front of the border. Although short-lived, new plants are likely to appear year
after year, since it self-seeds freely. H. 1ft. (30cm).
G. ibericum 'Johnson's Blue' Flowers growing proud of the leaves, finely cut
foliage. This is a particularly lovely variety with elegant blue flowers. A
clump forming plant with good ground cover characteristics. H. 2ft. (60cm).
BEST WHITE FLOWERS:
G. renardii Clusters of saucer shaped, white to pale-lavender flowers with bold
violet veins in early summer and velvety, rounded, sage-green leaves. This
stunning hardy geranium thrives in poor soil. A reliable and tactile foliage
plant, however it can be shy to flower. Excellent front of border and
groundcover. H. 1ft. (30cm).
G. macrorrhizum This pretty rock Crane's Bill is smothered with clear-white,
saucer-shaped flowers from July to October. It soon forms a strongly aromatic
carpet of deeply cut, light green leaves, which colour beautifully in autumn. An
excellent and reliable groundcover plant in full sun or part shade. H. 20in.
(50cm).
BEST PURPLE FLOWERS:
Geranium phaeum Nodding, reflexed petals in shades of deep maroon to almost
black. It makes excellent ground cover for a damp shady spot. Flowers: Spring to
Summer
H. 2 ft. (60cm).
Article
©MrsGreenFingers.co.uk 2005 No Unauthorised Distribution in full or
in part without express written permission.
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