If ever you decide to talk about ground cover be very aware of the company you are in. Some people will wince or grimace; others stifle a sneer. True, the phrase doesn’t conjure up images of Arcadia; on the contrary, it hints at invasive periwinkle or those bizarre dwarf roses covered in black spot, so popular in supermarket car parks. Since Graham Stuart Thomas wrote his seminal book on the subject thirty years ago, very few gardeners now talk about the value of carpeting plants. Ground cover has become démodé.
But the truth is that we all have parts of our gardens that would benefit from carpets of low-growing, spreading plants to cover the soil and to provide a respite from other, complex plantings. At this time of year Liriope muscari is not only doing a sterling job carpeting shady corners, but is also looking glorious.
Throughout the year it forms a thick and luxuriant mat of evergreen, dark-green glossy leaves, like hummocks of tufted grass. From the end of summer it starts to send up short flower spikes (the plant rarely reaches more than 10inches) that are covered in tiny violet bobbles. These are the buds that will gradually open throughout the autumn. They are so profusely produced that what was a sea of green is transformed into a violet carpet glowing in the golden autumn light.
The flower spikes themselves are slender and rounded, but more often than not you will see abnormally fat ones, or ones that seem to be flattened. Occasionally several stems appear to be squashed together. This is the result of fasciation, a condition that seems to often affect Liriope. (It is so common that photographs of the plant in major reference works such as Phillips & Rix’s Perennials and the RHS Dictionary of Gardeninng show fasciated plants). Even in the garden there are things that scientists are unable to explain and classify: fasciation is one of them. It appears to be some sort of hormonal imbalance that may be caused by a bacterium, but frost, insects and temperature also play their part. Whatever its cause, fasciation is a botanical oddity and not a symptom of disease, so don’t worry about it. It will not spread to other plants and will not necessarily recur from year to year. It certainly doesn’t affect the vigour of Liriope.
The white form, Liriope muscari ‘Monroe White’ has short white flower spikes that seem to lurk amongst the foliage. It is less vigorous than the species and a somewhat insipid plant that I’ve never warmed to. The variegated Liriope muscari ‘Variegata’, however, is majestic, with broad cream and green leaves that intensify the colour of the purple flowers. Another delightful Liriope, a cousin of Liriope muscari, is Liriope spicata ‘Gin-ryu’, with narrow silver and green foliage superbly complementing the purple flowers. Its unpronounceable name is often translated by nurseries and garden centres and so you will also see it sold as ‘Liriope spicata ‘Silver Dragon’.