Growing Daylilies: Planting, Care and Dividing

Daylilies have a reputation as perennials that carry on for years with very little help, and for the most part it is deserved. Growing daylilies comes down to a sunny or lightly shaded spot, soil that drains reasonably well and a little tidying in summer.

There are two things to settle before you buy: which types suit your climate, and whether cats use your garden. Both are covered below.

What daylilies are

Daylilies belong to the genus Hemerocallis. Each plant forms a clump of arching, strap-like leaves, and in summer it sends up leafless flower stalks called scapes. Every flower lasts about a day, but each scape carries many buds that open in turn, so a mature clump can stay in bloom for several weeks.

Varieties are sold as early, midseason or late, and some are rebloomers that flower again after the first flush. Heights range from about 1 to 4 ft (30 to 120 cm), and colors cover nearly everything except true blue. Bloom time and size vary by variety and climate.

Despite the name, daylilies are not true lilies. True lilies are in the genus Lilium and grow from scaly bulbs on leafy stems; daylilies grow from a crown with fleshy roots.

Hardiness and foliage types

Daylilies are widely adaptable and commonly cited as hardy across roughly USDA zones 3 to 9. That range covers the whole group, not each variety, so confirm it on the plant tag.

The detail that matters most is foliage type:

• Dormant daylilies lose their leaves in winter and regrow in spring. They generally suit cold-winter regions and can perform poorly where winters are very mild.
• Evergreen daylilies try to keep their leaves all year. They generally suit mild-winter regions and can be damaged by hard cold.
• Semi-evergreen types fall in between.

These are tendencies with many exceptions, so the practical rule is simple: buy varieties sold for your region, ideally from a local grower. Heat and humidity at the warm end affect flowering too, not only winter cold.

Sun and soil

Daylilies flower best in full sun, which means six or more hours of direct sun a day, and they also grow in part shade with somewhat fewer flowers. In hot-summer climates, afternoon shade helps the flowers last and keeps dark colors from fading. If you are unsure what a spot receives, the guide to assessing sunlight in your garden shows how to check.

They accept most garden soil as long as it drains reasonably well. Ground that stays waterlogged can rot the crown. Mixing compost into heavy clay or very sandy soil before planting helps both.

Planting daylilies

Daylilies are sold in pots or as bare-root divisions. Plant in spring or early fall in most regions, leaving several weeks before the ground freezes for fall plantings. In hot climates, the cooler part of the year is easier on new plants.

1. Loosen the soil to about a spade’s depth and work in some compost.
2. Dig a hole wide enough to spread the roots. For bare-root plants, make a small mound in the center and drape the roots over it.
3. Set the crown, the point where leaves meet roots, about an inch (2.5 cm) below the soil surface. Deeper planting can reduce flowering.
4. Space plants about 18 to 24 in (45 to 60 cm) apart, or as the tag advises, so each clump has room to widen.
5. Fill in, firm gently and water well.

Watering, mulch and feeding

Water new plants through their first season whenever the soil feels dry a few inches down. Established clumps cope with short dry spells, but flowering is better when they have moisture while the scapes and buds are forming. Check the soil instead of following a fixed routine.

A layer of organic mulch around the clump holds moisture and reduces weeding. Keep it off the crown itself; depth and materials are covered in the guide to mulching flower beds.

Daylilies are not heavy feeders. A top-dressing of compost in spring is often enough. If growth is poor, feed according to a soil test and the product label.

Tidying spent flowers and scapes

Yesterday’s flowers hang on as limp, wet tissue. Snapping them off is optional, but it keeps the clump looking fresh and stops them sticking to buds that are about to open. Remove any swelling seed pods at the same time unless you want seed.

When every bud on a scape has finished, cut the whole stalk off near the base. In fall or early spring, clear away dead leaves from dormant types before new growth starts.

Dividing crowded clumps

After some years a daylily clump becomes packed with crowns and produces fewer flowers. That is the signal to lift it and split it into smaller sections, each with a fan of leaves and healthy roots. Do it in cool, moist weather when the plant is not in bloom; early fall or spring suits many regions.

The full method, including tools and aftercare, is in the guide to how to divide perennials. Divisions are an easy way to fill another bed.

Daylilies and cats

If cats have access to your garden or to cut flowers indoors, the cautious choice is to grow a different perennial. A listing as non-toxic to dogs does not make a plant food, either. If any pet eats part of a daylily, contact a veterinarian or an animal poison control service promptly instead of waiting for symptoms.