The Common Knowledge About Chrysanthemum Care And Disease Control

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.