The chrysanthemum seems to have fallen out of fashion in modern gardens. One
reason why this has happened is that chrysanthemums are perceived as too much
hard work or troublesome. But there is less care involved than you may think and
they offer many positive attributes to gardens. They are great plants to choose
for this time of year, providing bold splashes of colour in the garden in late
summer and autumn.
Some varieties, such as florists' chrysanthemum, produce large impressive flower heads on strong, upright stems,
with colours that range from pure white, through every shade of pink, burgundy,
bronze and mauve to bright lime green.
The forms of these pretty flowers are even more diverse than the colours,
with more than 10 classifications, including: single and semi-double; regular,
irregular and intermediate incurved; quill; spoon; pompon; reflexed; anemone;
spider; decorative; and brush or thistle. The plant itself has a sturdy, upright
habit and attractive lobed, aromatic leaves. The flowers are long-lasting cut
flowers that can easily look good for up to three weeks in a vase. To get the
best from a bunch, change the water regularly and re-cut stems every few
days.
Chrysanthemums can be grown in the ground almost anywhere – at the front of
shrubberies, in perennial borders or under roses, to name just a few. Some dwarf
forms look great in rock gardens. Chrysanthemums grow well in pots and even
indoors with bright light.
Most people acquire a chrysanthemum when they are given a potted plant on
Mother's Day. In a pot, a chrysanthemum plant lasts for a few weeks inside. Keep
it in a brightly lit position and water when dry. Pick off any dead flowers or
discoloured leaves. When flowering has finished, take it outside, cut it back to
15cm and plant it out in your garden.
When choosing a spot, bear in mind that potted chrysanthemums may have been
treated with a growth regulator to keep them dwarf and compact, so they are
likely to grow much taller in the ground. Even though they can be grown from
seed, most chrysanthemums are propagated by cutting or by dividing clumps of an
existing plant.
Chrysanthemums grow best in an open, sunny position, although they can
tolerate partial shade, especially if it provides protection from afternoon sun.
They tend to prefer well-drained soil that has been improved with the addition
of compost and other organic matter. To perform well, they also must be fed
regularly with a liquid fertiliser every four to six weeks. At planting, add
some organic, slow-release fertiliser such as pelletised chicken manure.
Although they can be grown in the subtropics, chrysanthemums prefer a cool to
mild climate and a spot where they are protected from wind. If you are growing
them specifically to use for cut flowers, space them 60–75cm apart.
Chrysanthemums can be attacked by a range of pests and diseases, but they are
not hard to manage. Earwigs, snails and black aphids are all partial to the
flower and need regular control. If you spot caterpillars, such as the small
green loopers, spray with a biological insecticide such as Dipel or Success.
Although you can spray for leaf nematode, a problem that causes the lower
leaves to brown and die, picking off and disposing of damaged leaves at the
first indication of the disease is usually sufficient to stop it spreading.
Treat mildew with an organic-based fungicide, such as wettable sulfur or
eco-rose. If mildew proves simply to be an indication of poor air circulation,
improving this prevents it reoccurring.
Brown rust may affect leaves so pick these off by hand if the infestation is
bad, disposing of them in the rubbish bin. White rust is more troubling and it
is best to pull out the whole plant and dispose of it also in the garbage.