Geraniums are one of the most reliable plants in the home garden.
They can be obtained in flower in late spring and will add color
to the garden until frost. The new cultivars offer almost shatter-proof
flowers that withstand wind and rain. Geraniums can be obtained
as seedlings or established plants.
Set out plants in the spring after danger of frost is past. Geraniums
that have been injured by cold temperatures will produce little
growth and the foliage will often be red. Planting in late May is
preferable for the most productive plants. Plant geraniums where
they will receive sunlight for best flower production. Select a
site where water drainage is good.
will grow in almost any type of soil if well-aerated and porous.
Heavy clay soils should be improved by adding organic matter each
year. An inch of coarse sphagnum peat moss, partially-rotted manure,
or compost spaded in when preparing the beds is ideal.
plants are generally available as rooted cuttings or as seedlings
in plastic trays or pots. Plants should be set in the soil no deeper
than the depth they were growing in the pot. If possible, plant
more shallow--stem rot can kill plants if they are planted too deeply.
Once planted, firm the soil around the roots. Be careful not to
injure the stem of the plant, as this provides an opening for diseases
to enter. Water thoroughly after planting.
fertilizers such as 20-20-20 or 15-30-15 should also be applied
at the rate recommended on the package. Water after applying to
ensure that the fertilizer reaches the roots and to avoid burning.
Any fertilizer that gets on the foliage of the plants should be
sprayed with water.
plants can be started from stem cuttings, or "slips." Remove cuttings,
3 to 4 inches in length, from the tip of the stems. Shorter cuttings
can be taken if necessary. Strip off the lower leaves to facilitate
sticking the cuttings in the rooting medium. Perlite or sharp sand
alone or mixed equally with sphagnum peat moss is an ideal medium
for rooting cuttings. Place cuttings 1 inch deep in the medium and
water thoroughly. Place container in a north or east window until
rooted. Rooting occurs best with soil temperatures of 72 to 75 degrees
F. This generally takes 3 to 4 weeks. Water sparingly during this
rooting period--the trick to successful rooting is keep the cuttings
fairly dry. When cuttings have rooted, place them in 4-inch pots.
the cuttings become established (approximately 1 week), start fertilizing
with a liquid fertilizer such as 20-20-20 or 15-30-15 at one-half
the recommended rate of application. Make monthly applications thereafter
until the plants are planted outside in beds.
Pest problems are minimal with geraniums. Always keep fading flower
stalks removed to reduce botrytis, which can be a problem during
wet seasons. Proper plant spacing will help to minimize botrytis.
Bacterial blight can be a serious problem on geraniums--usually
evidence when the plant or single leaves wilt for no apparent reason.
Infected plants wilt most readily under high (70 to 80 degrees F)
temperatures. No sprays are available and the plant should be removed
from the site immediately.
It is possible to keep geraniums from year to year by taking cuttings
in late August and rooting them as discussed earlier. Plants can
also be dug, trimmed back to one half their original height, repotted
and placed in a sunny window for the winter months. Some people
also save geraniums by digging up the plants, removing soil and
hanging from the rafters in the basement on hooks. This method requires
high humidity (85 to 90 percent) and cool temperatures (50 to 55
are many types of geraniums. The majority today are produced from
seed. Look for plants in these seed-propagated families - Ringo,
Bandit, Elite, Orbit, Pinto, Multibloom and Lone Ranger - for good
results. Red cutting type geraniums that perform well include Kim,
Mars, Tango, Yours Truly and Sincerity. Pink and other varieties
include: Cherry Blossom, Helena, Katie, Pink Expectations, Pink
Satisfaction and Rio.
geraniums such as ivy-leafed, scented and Martha Washington can
also be grown by homeowners. Ivy-leafed
geraniums display a characteristic of trailing stems that make them
ideal for containers. Keep evenly moist in a east or north exposure.
Ivy types do not tolerate temperatures above 85 degrees F for long
type geraniums should be grown in full sun to develop the volitile
leaf oils. Flowers are less significant with this group, but the
soft scented leaves give fragrant oils that are useful in sachets.
Martha Washington or Regal geraniums are sold in early spring and
require cool temperatures (60 degrees F and below) at night to stay
in bloom. Warm summer temperatures will cause flowering to cease
until fall, when temperatures become favorable.
from Charles T. Behnke, Ohio State University Extension, 2000