How to Grow Daylilies USA

Quick Facts

Factor	Value
Drainage	Well-drained, fertile (RHS); NC State: well-drained preferred, tolerates poor soil, high organic matter/loam.
Lifecycle	Herbaceous, clump-forming perennial. NC State gives USDA zones 3a-8b.
Edible parts	flowers, flower_buds, shoots, tubers
Documented problems	2 diseases, 5 pests

At a Glance

Diseases

Daylily rust (causal agent not yet confirmed)

low

Southern blight

moderate

Sclerotium rolfsii

Pests

Hemerocallis gall midge

moderate

Contarinia quinquenotata

Named directly by RHS as causing distorted flowers and unopened buds.

Aphids

low

Aphididae (various spp.)

RHS: minor damage. NC State does not separately flag aphids.

Leafminers

moderate

Liriomyza spp.

Named specifically by NC State as Daylily Leafminer; RHS does not mention this pest, likely a US-specific pressure.

Snails

low

Gastropoda (snails, various spp.)

RHS: minor damage from snails.

Slugs

low

Gastropoda (slugs, various spp.)

RHS: minor damage from slugs.

Growth Stages

Stage	BBCH	Notes
Planting	0	RHS: plant in autumn or spring (summer possible with consistent moisture), crown level with the soil surface, spaced in multiples of three or five for visual impact; also suitable for containers. NC State: division of rhizomes is the propagation method, and clumps spread rapidly once established.
Establishment	3	RHS: little feeding needed, though a general-purpose fertiliser in spring can boost growth, and container plants need regular feeding through the season; avoid heavy shade, which causes straggly growth and poor flowering.
Flowering	6	NC State: flowers June to August. RHS: no staking needed; cut spent flowering stems to the base to encourage more blooms; rich flower colours can bleach in very intense sunlight.
Harvest and autumn tidy	8	RHS: remove old, faded foliage in late autumn or early spring for neatness, though old leaves provide overwintering habitat for beneficial creatures. Divide established clumps every three to four years in spring or autumn to keep them vigorous.

Harvest & Storage

When to pick: NC State: buds and open flowers edible, sweet-spicy or peppery flavour. RHS: only harvest from plants not specifically bred as ornamentals with confirmed edibility -- for unlabelled plants, grow on at least three months and harvest only subsequent flowerings, to reduce pesticide-residue risk. Caution: edibility applies reliably to the original Hemerocallis fulva; ornamental cultivars and hybrids should not be assumed edible.

Storage

Added fresh to stir-fries, salads and soups (RHS); NC State describes the flavour as sweet-spicy or peppery.

Sources

1. North Carolina State University Extension (Plant Toolbox) - Hemerocallis fulva (Daylily, Ditch Lily, Orange Daylily, Tawny Daylily, Tiger Daylily)

   Light: full sun to partial shade. Soil: well-drained preferred, tolerates poor soil, high organic matter/loam. Size: 3-6ft height (scapes to 6ft), 2-2.5ft width, forms large clumps. Hardiness: USDA zones 3a-8b. Native range: Asia (China, Japan); naturalised in Europe and North America, especially older US homesites. Propagation: division of rhizomes, spreads rapidly. Pests/diseases: Daylily Leafminer, Southern Blight of Herbaceous Ornamentals; otherwise no significant problems. Edibility: buds and flowers edible, sweet-spicy or peppery flavour; toxic to cats, non-toxic to dogs. Growth: low maintenance, rapid growth, moderate water needs, drought and heat tolerant.

These source is specific to this region. The full list of 2 sources behind this guide (North Carolina State University Extension (Plant Toolbox), Royal Horticultural Society) is in the references of our UK guide to daylilies; they describe the plant itself, which is the same wherever it grows.