How to Grow Hemerocallis, common name Day Lily
Hemerocallis, common name Day Lily, is a summer flowering plant. Each plant has multiple stems with many flower heads, ensuring constant flowers throughout the summer, even though each flower lasts for only one day.
Day Lillies are fully hardy H6 which is down to - 20C (mostly) herbaceous perennials return reliably each year. Day lily vary in size from small compact varieties of around 30cms to the taller varieties of up to 1.5m. Hemerocallis is long flowering with large trumpet-shaped flowers, often with stripes and attractive clump forming foliage. Even though each individual flower is short-lived, the plant will be in flower for around 4-6 weeks. The name Hemerocallis means 'beautiful for a day'.
Many Day Lilies are herbaceous, which means they die back completely in the winter, leaving bare earth and emerge in the spring with fresh growth. In milder areas, they can be evergreen or semi-evergreen.
How to plant Day Lillies
Day Lillies flower best in full sun but will tolerate partial shade. Full sun is the ideal condition for Daylilies to flower, but they can tolerate partial shade. Hemerocallis are not fussy about soil types and will tolerate heavier soils and, once established, they have some resistance to drought. It maybe that well-drained fertile soil is the ideal growing condition, Day Lilies are quite tough and will tolerate a range of growing conditions.
The reason I have tagged Day Lillies as an amber wheelbarrow plant is although easy to grow, they require some maintenance.
The taller, larger Day Lilies need to be staked. The new growth may look very upright as it emerges, but don't be fooled, the taller varieties of Day Lily look much better with some staking and support. In spring, (or when you get round to it,) as the growth emerges, place a support under their foliage to keep the plant upright and stop it collapsing later in the season when there are many blooms.
In terms of maintenance, Day Lilies need to be dead headed regularly to keep the plant looking good. Each stem has multiple flowers, which is good in the sense of making the plant attractive, but it means dead heading as the flowers are short-lived they need to be removed regularly to keep the plant flowering. After flowering, each stem can be cut to the ground. Once the plant has flowered and the foliage looks tatty, cut the foliage to the ground and it will reward you with fresh lush growth for the rest of the summer, although it will not flower again.
The plus side is that day lilies flower constantly from late spring to early- mid summer, with strong lush foliage and make excellent border plants. They form large clumps, see third image above right, and produce good strong colour. They look spectacular, producing large trumpet-shaped flowers in varying shades of yellow, orange, red and deepening down to crimson.
Although called a "lily" Hemerocallis is not in fact a member of the lily family, all of which are toxic to pets. Day Lilies are safe for dogs, but highly toxic for cats.
Day Lilies make an excellent cut flower.
Day lilies are an amber wheelbarrow plant as they need some attention and division with time, so not entirely maintenance free.
Hemerocallis gall midge
The image left shows Contarinia quinquenotata, common name gall midge damage on Hemerocallis flower bud. It was first observed in the UK in 1989 and is now fairly widespread. Day Hemerocallis gall midge does attack Lily flowers. This is a tiny fly that lays eggs in the flower bud between May and mid-July. The larva feed on the developing flowers buds, causing buds to become deformed or not open. The fly is only active until mid-July, later flowering varieties are not affected.
Credit for this very helpful image goes to Richard Avery on Wiki. You can clearly see, and I have annotated, the long unaffected bud with a cluster of shorter deformed buds which have been affected by the gall midge.
The larva are hard to see, being translucent. It is difficult to treat. Picking off the galls by hand is the best option, as is picking off all affected buds to try to arrest the spread.
The problem with using chemical controls is it will adversely affect visiting bees and pollinators, and not recommended.
How to Divide Day Lillies
To keep Day lilies flowering at some point, usually around every three/four /five years, the plants need to be divided because they become congested. The only way to do this is to dig up the plant, divide and replant. If you have day lilies which don't seem to be flowering as well as they did, this could be the problem.
The image shows the congested clump of day lily which has been dug up and place on a tarpaulin ready for division. Divide a clump by using a small saw and cut it into pieces. Then replant, the best pieces, all of which is hard work. The time to divide is late autumn or spring.
Ideas for some varieties of Day Lilies to grow
Good varieties with the RHS garden merit award are:
H. 'Marion Vaughn' lemon-yellow and 'Whichford' both are scented.
H. 'Pink Charm' has a starry shape and a salmon tinge.
H.'Gentle Shepherd' is pale pink second and centre image.
H.'Stafford' is a striking red with a yellow throat.
H. 'Elegant Candy Pretty' pink Hemerocallis with red eye and edge over green throat, and fragrant.
H 'Moonlit Masquerade' an unusual cream with dark purple.
There are dozens of varieties of Hemerocallis simple to grow in a good sunny spot.