Growing Daylilies University of Vermont ExtensionDepartment of Plant and Soil Science Summer NewsArticleGROWING DAYLILIESDr. Leonard Perry, Extension ProfessorUniversity of VermontThis plant is a favorite with gardeners as it adapts readily to a widerange of soil and temperature conditions, and is generally quite hardyand free from serious insect problems. It's an excellent plant forbeds and borders, but choose your location carefully as these plants canget rather large (one to three feet in height and across), shading or crowdinglower flowers and landscape plants.Ideally, daylilies prefer well-drained soil and bright, sunny locations.Flowers will open to face the sun or bright light, so place them with thisin mind. They will grow in part shade, but wont flower nearly aswell. A warm, sheltered, south-facing site may speed up bloom timeslightly.For best bloom daylilies require much fertilizer and moisture priorto bloom time.
How to Divide Daylilies. Daylilies are an easy, inexpensive, and pretty perennial to grow in your garden. They can be divided into smaller clusters that you can share with friends, or use to expand your own collection. Trim the daylily. Transplant your daylilies whenever you have time. Minimize the transplant shock and increase success by avoiding the hottest part of summer. Cold climate.
They will tolerate less fertilizer and poorer soils,but wont bloom as well. Apply granular, organic liquid-soluble, orfoliar-applied fertilizers according to label directions.Although daylilies in pots can be planted almost any time the soil canbe worked, early spring and late summer are the best times for diggingand transplanting. To propagate, transplant, or divide this perennial,either dig a portion off an established clump or dig a whole clump (theycan be large!), then divide. Work carefully to avoid damage to theroots, although some cutting is inevitable. A square-tipped spadeworks well.Set the crown (where the root and stem join) no more than one inch belowthe soil surface, spacing plants at least 18 to 24 inches apart. Be carefulnot to set plants too deeply since they may become stunted and will lackvigor.
When digging the planting hole, leave a mound of soil in thecenter to spread the roots over, then cover. Most important is to keepnew transplants well-watered to a depth of eight to ten inches.If plants are divided during mid-summer after bloom, cut the tops backto within four to six inches of the base. Keep your new plantingweed-free until plants become well established. Best flowering usuallyoccurs two to four years after planting.
Mulching around plants with anorganic material such as pine straw or ground bark chips will help conservewater and deter weeds.Once established, daylilies require little care and may grow for manyyears without division. Yearly addition in spring of compost andfertilizer around plants will help maintain best growth. Some cultivars(cultivated varieties) have foliage that lasts well into the fall and canbe cut back then or in the spring. Cut back foliage in late summeror early fall on cultivars whose foliage turns brown. When cuttingback, pull off any dead foliage and cut back other leaves to within a fewinches of the ground.Daylilies seldom get serious insect or disease problems in home gardens,although you might encounter three problems. If foliage is damagedas it emerges in early spring, from cold for instance, it may emerge distorted.This is often called “spring sickness”, and plants will usually begin togrow normally with good weather and care.Often appearing with such distorted leaves, more as a result of thembeing weakened, is “leaf streak” disease. It appears as brown streaksin leaves, and seems to vary with cultivar.
Remove such leaves if heavilydamaged, and keep plants healthy.If ordering from catalogs, inspect plants upon arrival and when plantedfor rust-colored dots on leaf undersides. Such could be signs ofa new “rust” disease, specific to daylilies but similar to those on otherplants such as hollyhocks. Remove and destroy any infected leaves.When choosing which cultivars to plant, in addition to personal preferences,choose those that either rebloom or choose a mix that blooms over a rangeof time. Visiting local nurseries every three weeks during summeris a good way to get such a mixed selection. A listing of Vermontspecialty nurseries, including those for daylilies, can be found online(pss.uvm.edu/ppp/vpdgli.html). Other specialty daylily nurseries,and more information on daylilies, can be found on the American HemerocallisSociety website (www.daylilies.org).