Nothing compares to the huge, fragrant blooms of the Oriental lily. Growing a metre to a metre and a half tall and producing stout stems on which a multitude of heavy blooms appear, they are nothing short of spectacular.
Orientals are not as hardy as the Asiatic and martagon lilies, so I treat them a bit differently. First of all, I plant any new bulbs in the spring. Fall planting is less successful while spring planting allows the bulbs to get well established before enduring our cold winter. Secondly, I plant Oriental bulbs a bit deeper than other lilies to offer them further winter protection.
The deeper planting (bulbs are covered by at least 15 cm of soil) also anchors the plants better as they are tall and heavy, requiring their roots to be well anchored in the ground. Just before fall frosts begin I mulch the lilies with dry leaves; this allows the plants to continue to harden off by keeping the soil warm, thus further enabling them to prepare to withstand the coming winter. In the fall, just before freeze-up, I place a large plastic bag (its original purpose was to hold a mattress) full of dry leaves over the lilies. I cut the tops off level with the ground and remove all leaves and stems. This is good practice with any lilies as disease organisms, such as botrytis, winter over in old foliage.
All lilies, including Orientals, prefer a well-drained soil that contains ample organic material. The soil should be rich in nutrients or else be supplemented with fertilizer. Lilies also demand sun so the best performance will be obtained by giving them a full sun exposure. Given much shade, they become leggy and weak stemmed and the blooms are more widely spaced along the stems. Lilies in shade will lean out toward the light and will often fall over if they are not provided with a support.
Botrytis is the most common disease problem. It first manifests itself when lower leaves become spotted; they gradually turn brown and die and this progresses all the way up to the top of the plant. Often the foliage will turn yellow before it turns brown. Botrytis does not kill the bulb but the blooms are lost and the plants are unsightly. To prevent botrytis, remove ALL debris in the fall and make sure the lilies are planted where there is good air circulation. Also, avoid watering late in the day as wet foliage encourages the disease.
Botrytis is a fungal disease so a fungicide can be used to prevent a recurrence. Spray the plants with a fungicide every two weeks, or if a home remedy is preferred, spray a baking soda solution on the foliage every three or four days. The only insect pest that bothers lilies is the lily beetle (Lilloceris lillii), that can be controlled by hand picking and by using a chemical such as End-All, which is an organic insecticidal soap produced by Safer.
All lilies, including Orientals, should be divided every three years or so, because the clumps get larger and larger and the bulbs become crowded. The flowers will get smaller and the plants will not be as robust as they compete for space and nutrients. The best time to do this is in the fall after bloom has ceased. Gently ease the clump out of the ground with a garden fork, being careful to get the fork underneath the whole clump so as not to pierce any bulbs. Plant the larger bulbs about 30 cm apart; the smaller ones can be spaced a little closer together (perhaps in a row somewhere in the garden so they can be dug in the spring to donate to a charity plant sale).
While Oriental lilies are relatively hardy in Manitoba when given adequate winter protection, there are crosses (hybrids) that carry the extra hardiness, such as the Orientpets and the LA lilies. The first is a cross between Oriental and Trumpet lilies while the LAs are crosses between the Easter lily (L. Longiforum) and the Asiatic lily. Both have strong stems, magnificent flowers and have proven themselves to be robust and dependable.
Lilies come in a wide range of colours, excluding blue and purple. Blooms often have colourful dots or paintbrush strokes on them, or bands of a contrasting colour running lengthwise on each petal. The blooms have a long vase life and a plant will bloom from two to three weeks in the garden. One year I cut a stem of my Oriental lily just as the lower blooms where beginning to unfurl and I held it in the refrigerator for a flower show for close to three weeks. When I put the exhibit on display the blooms burst open and the stem was spectacular — winning first prize!
By choosing varieties of all kinds of lilies that bloom at different times, the bloom period can be extended to last most of the summer. The Orientals are some of the last to bloom in the early fall; just another reason to include some lovely Oriental lilies in your landscape.