Advice
RHS Help & Advice
Daylilies
Common name: Daylilies
Latin name:Hemerocallis
Group: Herbaceous perennial
Cultivation
Daylilies thrive in well-drained, fertile soil, but tolerate poorer soils and heavy clay. Just avoid planting in heavy shade and borders that dry out in summer.
Before planting, improve the soil structure and moisture retention by digging in some well-rotted organic matter, such as garden compost or manure. The same materials can also be used as a mulch around existing plants in spring to help conserve moisture. A granular fertiliser, such as growmore, can be applied in spring too.
Pruning and training
Daylilies do not require training or staking and there is no particular need to deadhead after flowering, but this will improve their appearance.
Propagation
Daylilies can be divided in spring or autumn, but it is best to this only with large, established clumps. Split the clumps into sections about 10-15cm (4-6in) wide and replant about 30cm (12in) apart.
Problems
The main pest of daylilies is hemerocallis gall midge. The larvae develop in the buds, causing to the flowers to distort or fail to open. Damage mostly occurs before July, so choose late-flowering cultivars. Pick off and destroy galled buds, there are no chemical controls available to home gardeners. Slugs and snails can also be a problem, attacking young foliage.
Hemerocallis gall midge
Slugs
Snails
There are no significant disease problems. However, a new rust disease was found on an imported hemerocallis in 2001. Thankfully, it has not been reported in the UK since but remains notifiable. The typical symptoms are numerous yellow or orange pustules, mainly on lower leaf surface but occasionally on upper surface or stem.
Cultivar selection
Many cultivars can be found in nurseries, however these are recommended:
H. 'Cartwheels'
H. 'Green Flutter'
H. 'Pink Damask'
Click here for other recommended AGM varieities