Late-Flowering Chrysanthemums

By November, gardens are beginning to look rather shaggy and distinctly short of flower colour. That is why a number of the late-flowering hardy chrysanthemums can be such a boon to the gardener, especially in the reasonably dry, almost frost-free autumns that have become the norm over the last few years.

The types of chrysanthemum that are hardy in our gardens and flower in the autumn are the Korean, the rubellum and the Japanese semi-pompoms. They come in a wide range of colours and usually associate well with Michaelmas daisies (Aster), rudbeckias, echinaceas and Verbena bonariensis, which are the other great staples of autumn herbaceous plantings.

Like all the chrysanthemum family, these flowers are extremely useful for arranging in vases in the house, provided you don’t wait until the weather has done its worst before you pick them.

Hardy chrysanthemums make clumps, which are woody at the base, from which arise stems between 70 and 100 cm tall. The daisy flowers can be single, semi-double or fully double, depending on the variety. These hardy chrysanthemums do best in a well-drained, fertile, slightly alkaline (ideally) soil, in full sun. But they are really not very fussy.

Though they are reasonably sturdy, they are best staked, as autumn gales can be fierce and test the strongest stems. To make compacter, sturdier plants, you should follow the advice of Michael Loftus of the famous perennials nursery, Woottens of Wenhaston, who cuts these plants back hard in early June and removes entirely any spindly stems.

This is known as the ‘Chelsea chop’, because it is done about the time of the Chelsea Flower Show. It has become a very popular technique with gardeners in recent years as a way of staggering the flowering of many different types of hardy perennial. In the case of hardy chrysanthemums, however, the flowering happens at the same time, but you can get away without staking them.

In hot summers, such as gardeners in the south and Midlands have experienced this year, it pays to water chrysanthemums in very dry weather or the stems become rather stunted and straggly and the flowering isn’t good.

After the flowers go over towards the end of November, the stems should be cut down almost to ground level and, in really cold regions, the crowns should be mulched heavily with leaf mould or home-made compost, held in place with pegged-down chicken wire. That said, I forgot to do this before the last, very harsh, winter and they still came through fine. They benefit from being divided when they become congested, about every three years, but do it in the early spring, just as the new growth is emerging.

‘Cottage Apricot’ has single flowers, bronzy-apricot in colour, in October and November, on stems up to 80 cm tall. This plant flops rather easily, so it should definitely be staked. I think it’s one of the very best varieties, however, and provides a zingy contrast to all those pink, mauve and purple Michaelmas daisy flowers.

‘Anastasia’ is a pompom with purplish-pink, double flowers, that have yellow centres, up to 4 cm across. The plant grows to 75 cm tall. ‘Mei-kyo’ is very similar but has slightly paler flowers and is shorter.

‘Nantyderry Sunshine’ is a Japanese semi-pompom with cheeringly bright yellow double flowers, 3 cm across, in October and November. It is a sport from the equally garden-worthy ‘Bronze Elegance’.

‘Ruby Mound’ is a popular variety because it makes a dense, short plant, and the double 7 cm flowers are a deep, satisfying red in colour.

‘Emperor of China’ flowers particularly late, in November and December. It has a laxer, taller habit than most, and double, 6 cm diameter flower heads in a very soft pink. The petals are slightly quilled, which is most attractive. What is more, the leaves turn red in autumn. Its late flowering, however, can sometimes mean it gets clobbered by horrible weather.

‘Purleigh White’ grows to about 85 cm, and has white semi-pompom flowers with just a hint of pink, and prominent yellow central discs. It is a sport of ‘Mei-kyo’, so has the same habit but a different-coloured flower.

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