Oriental lilies are not daylilies, but are real lilies. They grow from spherical bulbs that normally sprout one main stem. Narrow leaves circle the stem top to bottom. Oriental lilies grow 24 to 72 inches tall. The lily bulbs do not keep well in cold storage for more than nine months. This makes them hard to purchase from January through March.
Oriental lilies produce large 6- to 8-inch, highly perfumed flowers. The blossoms are red, purple, pink or white. The flower buds develop on top of the stem and open in sequence from lowest first to the top, which is the last to open. The exotic-looking blooms are almost flat and star-shaped when opened all the way. Petals have a ruffled edge and colored speckles. The flowers bloom in late summer. Oriental lilies produce the best blossoms in full sunlight with a minimum of eight hours a day. Without enough sunshine, oriental lily flowers will not be as abundant.
Mix lots of peat moss into the soil when planting oriental lilies to improve the acid level of the soil. These lilies enjoy an acidic soil pH of 6.5 to 6.8. The lilies need a good-draining soil, so add sand if you have any drainage issues with your flower garden. Plant the lilies in the fall or spring to a depth of 8 inches with 4 to 6 inches between bulbs. Mulch the lily plants when the soil begins to freeze. Spread 4 to 6 inches of wood chips or straw over the top of the bulbs. Oriental bulbs are susceptible to cold damage when temperatures fall below 23 degrees Fahrenheit.
The most common oriental lily is the stargazer lily. This lily is a popular forced flower for Mother's Day. It produces large pink flowers with white edges. Spots of red freckle the petals. Each lily has four to five flowers per stem growing 36 inches tall. The blossoms are dramatic when set above dark green leaves. Stargazer lilies normally start flowering in mid- to late June.
Lily leaf beetles (Lilioceris lilii) eat oriental lily leaves and flower buds leaving bare stems behind. They only lay eggs and live on true lilies. These beetles are natives to Europe. In 1945, the lily leaf beetle invaded Canada. By 1992, the beetles had invaded the northeastern area of the United States. The beetles hitchhike on shipments of lilies to travel around the world. Each female lily leaf beetle lays 250 to 450 eggs.
Handpick the adult lily leaf beetles and their eggs off your oriental lilies if you only have a few infested plants. If the infestation is unmanageable by hand then use a pesticide treatment. Products that contain neem will kill the young larvae. Apply these products five to seven days after the beetle eggs hatch. Another option is to use biological control in the form of parasitic wasps released in your lily garden.