Hardy perennial plants that come into bloom in late summer and go on into November are always welcome in the garden — and the garden centre — especially as few fit into this category. L. muscari Award of Garden Merit (AGM) does just that and has the added bonus of producing a sizeable clump of deep green, evergreen, glossy, strap-like foliage which makes excellent ground cover.
The common name for plants in this genus is “lilyturf”, derived from the fact that the clump-forming varieties appear grass-like when not in flower, and they are members of the lily-of-the-valley family (a subdivision of the wider Liliaceae plant family). About eight species of Liriope come from China, Japan and Vietnam, where they inhabit woodland edges and scrub. Only four species are commonly grown in UK horticulture.
Most are late-flowerers, adding a welcome touch of colour to the autumn border. Small, bell-shaped flowers are held erectly in short, upright spikes among or above the leaf tips and are followed by purple-black berries. Contemporary designers are increasingly appreciating them as foliage plants.
All forms of Liriope have fibrous roots with scattered water-retaining tubers supporting narrow grass-like foliage. These tubers give the plants a high drought tolerance. Plants vary in habit from tightly clumping to widely colony-forming.
Liriope plants are best in part shade but tolerate a position in full sun — indeed, sunshine is required for the later-flowering species. Most soils are suitable as long as they are fertile and well-drained. Cold, heavy or waterlogged soils are not suitable.
Left alone, the plants will produce sizeable clumps, and many years can pass before they show any signs of deterioration.
Plants can be tidied up in the spring by cutting back the foliage, which should be carried out before new growth starts.
The most common form of propagation is division in spring, although species can be raised easily from seed. If outgrowing their position, Liriope plants are not difficult to keep in bounds by lifting and dividing. New growth in spring can be prone to attack from slugs. Other than that, there are usually no problems with pests or diseases.
Many are mistakenly listed in catalogues under the closely related Ophiopogon, which differs in its nodding flowers and white-striped foliage. The name ‘Silvery Sunproof’ has been used for a number of different variegated cultivars.
What the specialists say
Paul Greene, horticulture tutor and National Collection Holder, Brooksby Melton College, Leicestershire “Liriope is considerably more popular in the US where a lot of breeding work has taken place. The plants originally come from China and Japan but it’s in the US, where the plants are popular as ground cover, that the modern development work is happening.
“They are very adaptable plants. Our National Collection, which has almost 50 species and cultivars, is mainly sited within the shade of an old oak tree. Here the ground is dry, shady and fairly hungry, but Liriope seems to do well.
“There are a few forms that are particularly eye-catching. L. muscari Award of Garden Merit (AGM) is certainly the most popular, and can be very colourful when established. L. muscari ‘Superba’ is a strong grower with deep-coloured flowers. The variegated forms, particularly L. muscari ‘Gold-banded’ and L. muscari ‘John Burch’, make people stop and look. L. ‘Samantha’ is a good colour departure. It is listed as pink but has a tinge of lilac.
“As for maintenance, these are easy plants. We just clip over them in early spring to keep them tidy — that’s all they seem to need. In the US they go over them with rotary mowers.”
Peter Cantrill, proprietor, Dayspring Plants, Devon “We are a wholesale supplier, and we sell two-litre plants of L. muscari AGM, as well as the variegated version and L. muscari ‘Monroe White’. The straight species, with its violet-blue flowers and deep green foliage, is the most popular by far.
“It is fair to say that people need to be patient with these plants. Although they can flower in the first year they usually take a few years before they get to a good size, and then the flowers really become worthwhile. The bigger the plant, the better the flowering.
“Garden centres should promote this fact — they’ll sell bigger plants as a result. The other thing to promote is that these are generally shade-loving plants.”
Peta Marshall, plant centre manager, Priory Farm, Surrey “There is a danger that if you keep Liriope on A-Z benches the plants can be swamped by larger, more eye-catching plants. In their flowering period, therefore, they should be removed and put into hot spots. The larger plants will have better flower spikes.
“Don’t just promote them as good herbaceous plants. Use point-of-sale material to make customers aware that these are good plants for shade, and make good ground cover.
“It’s not unreasonable to have several displays of them around the planteria, particularly as there are few flowering plants during the September-to-November period.”
Species and cultivars
• L. exiliflora has deep green, leathery leaves and long, mauve, bell-shaped flowers held on violet-brown stems. It can be aggressive if happy in its position. Sometimes sold as L. muscari var. exiliflora.
• L. exiliflora ‘Ariaka-janshige’ has leaves striped white and yellow. It is also sold as L. ‘Silver Sunproof’.
• L. koreana has long spikes of bright purple flowers in August-September, followed by black fruits.
• L. koreana ‘Majestic’ has tall flower spikes with thickened or crested tips. It is one of the most popular cultivars.
• L. muscari Award of Garden Merit (AGM) is arguably the showiest and certainly the best-known species. It forms dense clumps of deep green, leathery leaves up to 45cm long. Violet-blushed stems carry dense spikes of violet-blue bells in autumn, often continuing into winter.
• L. muscari ‘Argenteovariegata’ has silver stripes on the leaves.
• L. muscari ‘Big Blue’ is similar to the species but with larger flower spikes.
• L. muscari ‘Christmas Tree’ is a rarely seen narrow-leaved form with spikes of pale pinkish-white flowers in mid- to late summer. It is a slow grower and smaller than most forms, reaching about 15cm.
• L. muscari ‘Evergreen Giant’ has longer, larger leaves than the species and lilac-purple flowers.
• L. muscari ‘Gold-banded’ carries a central greenish-yellow stripe along each mid-green leaf.
• L. muscari ‘Goldfinger’ is a recent introduction with bright blue flowers set against deep golden-yellow strap-like leaves.
• L. muscari ‘Ingwersen’ has green leaves and carries dense spikes of lilac-blue flowers.
• L. muscari ‘John Burch’ has a central golden-yellow stripe along each mid-green leaf. The leaves are wider and taller than those of L. muscari ‘Gold-banded’.
• L. muscari ‘Lilac Beauty’ has lilac flowers.
• L. muscari ‘Monroe White’ produces pure white flowers that are larger than most of the blue forms.
• L. muscari ‘Okina’ has foliage that is the main attraction. Young leaves are white, ageing to a frosty green with pure green tips.
• L. muscari ‘Paul Aden’ has pale primrose yellow and green leaves, and violet flowers.
• L. muscari ‘Royal Purple’ carries dark purple flowers.
• L. muscari ‘Silver Ribbon’ has intensely silvered foliage on a compact plant. It rarely flowers.
• L. muscari ‘Silvery Midget’ produces short, yellow variegated leaves. Its flowers are mauve and appear during October and November.
• L. muscari ‘Superba’ has tall, grassy leaves and violet-purple flowers from October to December.
• L. muscari ‘Variegata’ has leaves margined yellow and lilac-blue flowers.
• L. muscari ‘Variegated Alba’ is often sold as ‘Variegated, White Flowered’, which describes its appearance. It is slow growing and appears to be a little more tender than most forms. It prefers dryish shade.
• L. muscari ‘Webster Wideleaf’ has wide, dark green leaves and dark purple flowers.
• L. ‘Samantha’ produces distinctive pink flowers in showy spikes.
• L. spicata is the most effective species for ground cover, as it spreads widely by underground stems. The deep green leaves are particularly grass-like, and the summer flowers vary from almost white to pale lilac.
• L. spicata ‘Alba’ is pure white.
• L. spicata ‘Gin-ryu’ is compact, with silvery white striped foliage. It is often sold as ‘Silver Dragon’.
• L. spicata ‘Small Green’ is a small, quick spreading form with pale violet, almost white flowers and dark green leaves.