Daylilies grow best in direct sun or light shade. They perform best with six hours or more of full sun daily. More sun normally results in more flowers.
Daylilies prefer a slightly acidic (pH 6 to 6.5) garden loam with good drainage and ample humus. However, they are adaptable to many soil types. Our gardens are nasty orange clay amended with compost. Still basically clay-gets a little better every year.
Planting may be done between April and September as long as water is available in my zone 6. Spacing generally is two feet between each plant (15 to 18 inches between miniatures).
Daylilies prefer to be kept moist, but not constantly wet. Water should be thoroughly applied following planting until the plants are established. Consistent watering during the flowering period encourages high quality flowers. Once established, daylilies are remarkably drought tolerant. We do not water established plants. Our general conditions at my farm are VERY wet early spring (dig a four inch deep hole on a gentle incline and 4 days after rain and it still full of water), wet June, July, very dry mid August-mid September (ground is cement like), then slowly getting wetter fall-winter.
Daylilies usually grow well with minimal fertilizer applications. However, if a soil test indicates the need for fertilizer, apply it in early spring or late fall. Avoid fertilizers containing too much nitrogen because excess nitrogen encourages flowers with extremely tall stems that break easily. I STRONGLY recommend having a soil test done before applying any fertilizers. These are available through most state's agricultural extension office for a modest charge or free in some states. The test will tell you exactly what fertilizer is needed. You will most likely save money while providing a correct application of fertilizer/lime. Over fertilization can be worse for your plants than under fertilization. After our original soil tests, I've been using only Milorganite in the spring. It reportedly helps repel deer. I can only say the deer didn't come this year untill about 4 weeks after I applied it. Right in the middle of bllom season. I'll try applying a second time or delay the first application in 2015 to see if that helps.
Mulch is not necessary, but helps to conserve moisture in the soil and control weeds. When choosing a mulch, consider ease of application, durability, attractiveness, moisture retention, cost, and availability. I prefer something natural and organic. Over time these will improve the quality of your soil. Addition of compost will help build your soil for all of your garden plants. We mulch with composted horse and chicken manures. These are surprisingly attractive and do not smell (more than a few days) if properly composted. We are fortunate to have a free source for both of these. Check local stables to see what they do with their manure. They’ll probably be more than happy to give you some. I found one that will even load my truck for me and thank me for taking it.
Daylilies are relatively free of pests and disease. One notable issue is Daylily rust, caused by the fungus Puccinia hemerocallidis. It was identified on daylilies in southeastern United States in the summer of 2000. It is generally only a problem in the South. Reportedly it cannot withstand our winters in zone 6. I can only confirm that the few plants I've received that developed rust did not have it the follwing year. Daylily rust is easily identified by localized, small orange pustules that contain orange, dust like spores. These pustules are located primarily on the underside of leaves. The affected leaves discolor as they dry up. To distinguish between daylily rust and daylily leaf streak (another fungal disease), simply scrape a pustule with your finger. An orange streak of spores is very diagnostic for daylily rust. Daylily rust is reportedly not able to withstand cold winters. Other pests of daylily include slugs, but they can be prevented by the use of slug bait and removal of dead leaves and old bloom stalks. Aphids, red spider mites and thrips are occasional pests of daylily. These are generally mild problems. We do not use insecticides in our gardens, preferring to allow a natural balance of nature to provide predatory insects to control the population. Adding compost and spraying with compost tea helps plants resist and recover from damage. Some varieties are susceptible to "Spring Sickness," which seems to be related to sudden freezes and thaws in northern climates. Selecting hardier more dormant varieties can reduce this problem. Daylilies grown in healthy soil are generally able to withstand any pest invasion. Daylilies should be divided every 3-5 years.