Lilies are now in mid-bloom in a variety of colors and they will probably continue to put on quite a good show for another few weeks. Lilies are perennial plants that are relatively easy to grow; most varieties are hardy in Minnesota and can fill your garden with hundreds of beautiful blooms throughout the summer. True lilies such as the Asiatic and Oriental belong to the genus Lillium. Other plants have lily-like flowers and may even have the name lily in their names, such as daylilies, calla lilies and canna lilies, yet are not true lilies. But all produce flowers in a wide variety of colors and fragrances that are trumpet, bowl or bell shaped and many of them have similar planting and growing requirements.
Asiatic and Oriental lilies grow from bulbs and have stiff stems with narrow strap-like leaves from bottom to top. Asiatic lilies are the easiest to grow and the hardiest in our climate, as long as they are in well-drained soil. They generally require no staking. Oriental lilies are also hardy in zone 4 as long as they are in organic, slightly acidic soil that is well drained, and they are mulched in the fall. Oriental lilies exhibit exotic blooms with a heavy sweet perfume.
Lilly bulbs can be planted from mid-September to mid-October. However should you have lily bulbs at another time of year they should be planted as soon as possible – they never really go totally dormant, so they should not be allowed to dry out. Plant lily bulbs in groups of three or five in full sun; that is six to eight hours of sunlight daily. Less sunlight will result in plants that are taller, spindly and floppy. They should be watered early in the day at the base of the plant. At night wet leaves make the plant susceptible to botrytis blight, a fungus which produces reddish brown leaf spots. Space your plants far enough apart to allow for adequate air circulation, which also helps prevent foliar disease.
Fertilize lilies each spring with a 5-10-10 fertilize and they will reward you with blooms ranging from four to six inches in diameter (depending on the cultivar) that will last for many days, even a week. Also depending on the cultivar they may bloom anytime from June through September. After the bloom has faded, break off the dead blooms carefully but leave the stems and leaves intact so that they can continue to make food to store in the bulb for next year.
Besides the botrytis blight, lilies have few other pest problems, but rabbits and slugs can be a threat to the tender emerging sprouts in the spring. Occasionally, you may find aphids sucking on the plants but they can be usually be managed with a strong spray of water.
Daylilies belong to the genus Hemerocallis; hemera is Greek for day and kallos is Greek for beauty. Each bloom lasts for one day; however newer cultivars have been developed that bloom in the evening of one day and remain open until the evening of the next. Each plant can send up several flower stalks and each stalk can produce many flower buds, each of which can bloom on a different day. Thus you can have a plant in bloom for many weeks. There are over 35,000 cultivars of daylilies that are named, registered and marketed. The cultivars can be hardy throughout a wide range of zones. To ensure that your lilies are hardy to zone 4, buy from local growers.
Calla lilies and cannas, while they have lily-like flowers, are not true lilies and they are not hardy to zone 4. Calla lilies are related to jack-in-the-pulpits but are native to Africa where they are considered weeds. Cannas are native to subtropical and tropic climates. Cannas and callas can be grown in our zone if they are planted in hot sites and the rhizomes are dug up each fall, stored over the winter and replanted each spring.