The lily (Lilium) is a genus in the lily family (Liliaceae). There are around 110 species and a large number of hybrids that have been created by crossing different species. At present, it is assumed that there are about 2,000 hybrids, which are grouped into eight groups – for example, the so-called Asian and Oriental hybrids. The pure species have their natural distribution almost exclusively in the northern temperate and subtropical zone, especially in areas with high precipitation. The Madonna Lily (Lilium candidum) is an exception as it prefers the dry climate of the eastern Mediterranean. The native species is the Turkish lily (Lilium martagon), which can be found in the southern Black Forest, for example, as well as in the Allgäu Alps. It thrives in herbaceous deciduous or coniferous forests on limestone and primary rock soils in a semi-shady, cool location. In the highlands it also grows above the montane forest on meadows and mats. Particularly impressive is the large-flowered and rich-flowered royal lily (Lilium regale) from China with its trumpet-shaped flowers.
Lilies are among the oldest cultivated plants. The Madonna Lily was already planted in gardens in the middle of the second millennium before Christ. The Romans introduced them to their provinces north of the Alps. In the Middle Ages the radiant white lily developed into an important symbol of Mary, as many paintings from this period prove.
Appearance and growth
Lilies are persistent, herbaceous plants with a scaled bulb as a survival organ. The fleshy scales that cover each other like roof tiles are, botanically speaking, modified leaves and serve as nutrient storage. Since this bulb, unlike other bulbous plants, is not surrounded by a protective outer skin, it is called “naked”. A special feature are the so-called draught roots, which develop on the onion soil and can draw the onion deeper into the soil. In addition, most lilies form roots in the subterranean stem area, where small daughter bulbs can also develop. Most species do not form basal leaves. Instead, these are mostly sessile and alternate, but are also often found in whorls on the flower shaft.
The growth height is between 30 and 240 centimeters, depending on the species. At the end of the stem one or more flowers form, which then stand together as a cluster or umbel. There are three types of flowers: trumpet-shaped, shell-shaped and the flowers of the Turk’s Lilies. In the latter, the petals are rolled far back so that their tips approach each other again on the stem. The blossom is reminiscent of a turban. The different species flower between May and September and with the exception of blue almost all colours are represented. After fertilization, three-chambered brown capsule fruits ripen, containing numerous flat seeds. The above-ground parts, i.e. stems and leaves, die after seed ripening. The stalk, leaf and flowering plants for the next year develop in the long-lasting bulb.
Location and soil
Which location and soil lilies need varies slightly from group to group. Therefore, it is best to inform yourself about the exact requirements of your lily directly at the time of purchase. Asian wild species, for example the saffron lily (Lilium bulbiferum ssp. croceum) or the tiger lily (Lilium lancifolium), the Easter lily (Lilium longiflorum) and their hybrids prefer a sunny to semi-shady location with a fresh, humus- and nutrient-rich as well as permeable soil. The Turkish lily and its numerous hybrids have similar claims as the Asian game species, a half-shady location is preferred – just like from the Oriental game species – however to a sunny one. The substrate may also contain lime. The Madonna Lily also likes it a bit calcareous, but prefers a place in the sun with a fresh, loose soil. The American wild species such as the panther lily (Lilium pardalinum) and its hybrids prefer lime-free soil. They can also cope with a slightly damp soil. All lily species thrive best in a weakly acid substrate. It should be noted that although most lilies require a sunny location, the soil around the plant should be shaded. This can be achieved with a low accompanying planting. As an alternative, a mulch layer of compost or bark humus can be used.
Compared to other bulbous plants such as tulips and daffodils, the bulbs of lilies do not have a firm outer skin. Therefore, they should never be stored freely and unprotected for long periods of time. The bulbs are planted between September and March, but spring planting is becoming increasingly common, as flowering can be extended over a longer period of time with slightly offset planting dates. For the Madonna Lily we recommend a planting period from the end of August to the end of September.
In order for lilies to thrive, a few things should be taken into account when planting them: A 25 to 30 centimeter deep planting hole is cut out. The drainage consists of a roughly ten centimeter thick layer of coarse gravel, followed by a five to ten centimeter thick layer of a soil mixture consisting of one third each of sand, garden soil and rotten compost. The onions are placed 10 to 15 centimeters apart on this earth mixture and wrapped in sand. The planting hole is then filled with the soil mixture already described. In heavy or loamy soils, it is easy to accumulate moisture, which lily bulbs do not tolerate. Then, the creation of an elevated bed or the hill-planting is recommended. An exception to the recommended procedure is the Madonna Lily: as it forms native leaves, the onion may only be covered with two to four centimeters of humus soil.
The faded stems are cut off immediately after flowering. This avoids unnecessary loss of strength due to seed formation. Only when you want to harvest seeds do you let them mature. However, the leafy part of the stem remains standing. Only when the leaves die, the stalk is cut off just above the ground. The remaining part with the stem roots is pulled out in spring and covered with humus-rich fertilised soil or mature two-year compost about five centimeters high. In early spring, even before the budding, lilies are supplied with a complete organic or mineral fertilizer. However, the nitrogen content should not be too high. They receive another one to two fertilizers during the sprouting process. A liquid fertilizer is recommended for this.
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Madonna Lily, Turkish Lily and Fire Lily are classic plants of the farm garden. There they are often combined with perennials and annual flowering plants in the sunny bed. If you want to emphasise the effect of the large colourful flowers of many hybrid varieties, you should surround them with a rather discreet colour scheme and give them a calm background, for example of woody plants with dark green foliage or needles. Many lily varieties can be cultivated very well in sufficiently large pots and are also extremely popular as cut flowers.
Important species and varieties
Among the more than 2,000 lily species and varieties there are numerous particularly beautiful specimens – so it is no wonder that many gardeners are sooner or later seized by “lily fever”. The Asian lilies are offered particularly frequently in the trade since they come up with particularly splendid blooms and – at least most of them – are quite easy to cultivate. The Madonna Lily has been planted in gardens for centuries as a symbol of purity and innocence – and of course because of the beauty of its graceful pure white flowers. Also widespread is the Turkish lily with its conspicuously rolled up, often patterned petals in various colours.
Lilies can be sown, but it can be assumed that this type of hybrid propagation does not produce pure plants, i.e. the offspring have different characteristics from the mother plant. In this way, new varieties can also be created. The best time for sowing is from January to the end of February in a warm location with a temperature of 15 to 20 degrees Celsius, depending on the species. The more common method is vegetative propagation – especially when plants with the identical characteristics of the initial variety are desired. During the resting phase of the plant, scales or daughter bulbs are separated from the mother bulb and replaced. A piece of the onion soil must still adhere to the separated scales so that they can take root. Preferably, they are first cultivated in pots, preferably in a 10 to 12 degree Celsius warm place. It takes up to three years for the newly harvested plants to bloom. Many lilies also form breeding bulbs at the subterranean stem base, so-called stem bulbs, which can also be planted. Gardeners recommend placing them in pots with a sand-peat mixture and wintering in a dark and cool but frost-free room. In spring you can plant them in the bed. Some types like the fire-lily (Lilium bulbiferum) also form bulbs in the armpits of the foliage-leaves. These are removed in August and placed two to four centimeters deep into the earth.
Diseases and pests
Lilies are susceptible to various plant diseases and pests. In warm and humid weather, grey mould (Botrytis) may occur. This mainly attacks the leaves and petals, but also the bulb. The disease can be recognised by the reddish-brown spots on the leaves, which are constantly increasing in size. In dry weather, the course of the disease stagnates. If the stem is also infected, it often breaks off at the infected site. The fungus can weaken the lily in such a way that all parts of the plant above ground die off. In the next year, it sprouts again, but since the fungus often survives in the soil, the disease can break out again. As a preventive measure, lilies should not be planted too densely, and plants can be strengthened by spraying them with horsetail extracts. Pollination with lava stone flour also has a positive effect. Another disease is onion soil rot (Fusarium). It can be largely prevented by taking care to plant only really healthy onions and choosing a sandy soil as the location.
Vole-mice represent a big danger for lily-onions. When the rodents are active in the garden, lily bulbs are placed in wire baskets in the soil. Another pest is the lily chicken, a red beetle that feeds on the leaves of the lilies. The insects usually occur several times a year in attacks and can be easily collected to prevent further spread. The larvae of the beetle can also cause damage to the foliage and should therefore also be collected. It is recommended to pollinate the affected leaves with rock flour. It is also effective against aphids. The lily fly, which can occur from May to June, causes damage to the flowers. The females prick the still green lily buds and lay their eggs in them. The larvae then destroy the inside of the flower through their food. The use of a systemically active insecticide alone helps against this.
In an interview with our store editor Dieke van Dieken, plant doctor René Wadas reveals his tips against aphids.Credits: Production: Folkert Siemens; Camera and Editing: Fabian Primsch
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.