Giant lily, Cardiocrinum giganteum – cultivation and care

The giant lily originally only comes in three different species, all of which are native to Asia. In the trade, they are among the rarities for garden lovers, who usually give them a place of honor in their garden.

• Chinese giant lily: growth height up to 80 centimeters,
• Heart-leaved Japanese giant lily: growth height up to 2.5 metres
• Himalayan giant lily: growth height 2-4 meters, in two subspecies:
  • Common Himalayan giant lily
  • Red-stemmed Himalayan giant lily

Only the largest species of giant lilies, the Himalayan giant lily, is usually referred to as Cardiocrinum giganteum.

From the seeds grow upright shoots with rosettes of heart-shaped leaves that have a glossy dark green surface. Giant lilies are perennial plants that do not flower until the end of their lifespan. A little patience is therefore required, but it pays off. The giant lily blooms after about three to five years. Then it develops a strong, often meter-high flower stem with four to twenty trumpet-shaped flowers. The flowers are mostly pure white, have a strong scent and can reach a size of up to 20 centimeters. Some hybrid species have a colored or dark background or have pink-red flower edges.

location

Giant lilies prefer a semi-shady place in the garden and loose, nutrient-rich and always moist soil conditions.

• Flowering time: from June
• Light requirements: half-shade to half-shade (no full sun)
• high humidity
• sheltered from the wind
• Soil: rich in nutrients, moist and deep
• Sandy-loamy or sandy-clayey soils are well suited.
• Good water storage capacity
• No waterlogging!
• Also tolerates peaty or slightly calcareous soils.
• Ideal: at the edge of the forest or under tall deciduous trees

plant

Although Cardiocrinum giganteum can also be planted in autumn, spring is much better suited. Giant lilies look best when planted in groups of three to five. From time to time young plants are available in pots, but more often giant lilies are offered as bulbs. You can plant them directly in the garden soil from the frost-free spring.

• Planting distance: about half the growth height, depending on the species between 30 and 80 centimeters
• Heavy soil: Dig a pit at least 70 centimeters deep.
• Build in old pieces of branch or bark, woody stems or other materials as drainage (at least 15 centimeters) at the bottom.
• Fill up with forest or leaf soil, humic garden soil or compost-mixed soil.
• Only plant onions so deep that the shoot tip protrudes slightly above the ground.
• Cover the bulbs with a maximum of ten centimeters of soil.
• Mulch well after sprouting to keep moisture in the soil.
• Water lightly and keep moist at all times.

maintenance

In general, the giant lily is one of the low-maintenance plants. If it is in a favorable place in the garden, the soil only has to be kept slightly moist at all times. It must never dry out, but it must also not develop waterlogging. If the soil is rich in nutrients and humus, no additional fertilizer is necessary in the first few years. In nutrient-poor soils, you can increase the nutrient content with long-term fertilizers such as horn shavings. In the year in which the Cardiocrinum giganteum develops its flowering, you should definitely fertilize additionally. During the development of the flower stem and the ripening of the seeds, the plant needs significantly more nutrients, otherwise the seeds will be stunted (and less germinable). Giant lilies do not require pruning during the year or before winter.

harvesting the seeds

For propagation from seeds, species of Cardiocrinum giganteum that are fixed to seeds are necessary. These include well-established cultivars and original varieties. Hybrid species are not very suitable for propagation. They are either very difficult to germinate or look completely different in the next generation. In addition to a good supply of nutrients during the flowering period, the giant lily also needs enough water. However, the soil should never be really wet, just damp. Towards the end of the flowering period, watering is significantly reduced to allow the seeds to ripen faster. The seeds of the giant lily ripen in a pod. Ripeness is reached when it turns brown, dries and opens slightly at the base. Post-drying on a dry, absorbent cloth may be necessary. The seeds are

sowing

The seeds of the giant lily must be exposed to a cold period for a few weeks before germination. To do this, mix the seeds with moist sand and put them in the refrigerator (vegetable drawer) for about 10-12 weeks. Only after this time you can sow the seeds in substrate in flower pots or a greenhouse. The best time for the cold phase (stratification) is in winter (November/December). Sowing takes place about three months later.

• When: In spring in pots outdoors or in a cold, frost-free greenhouse
• Alternatively, place in an unheated stairwell.
• Substrate: cactus soil, potting soil
• Moisten the substrate slightly.
• Put in the seeds and only lightly cover them with soil.
• Germination temperature: Around 10 degrees, do not keep too warm (germination fails at high temperatures).
• Place the pots outdoors in partial shade.
• Cover with a pane of glass or foil for better moisture regulation.
• Bright location without direct sunlight.
• Germination time: irregular between 8 and 24 weeks.
• Keep soil constantly slightly moist.

You have to be very careful when pouring. A gush of water from the watering can easily wash away soil and seeds. Therefore it is easier to mist the soil with the spray bottle. Since the pots are usually quite small and you only moisten the surface, the effort for this is kept within limits.

The right substrate

High demands are placed on the substrate. Not every garden or potting soil is also suitable for growing plants from seeds or cuttings. A good seed soil should have the following properties:

• poor in nutrients (the young plants do not tolerate high salt levels)
• good storage capacity for water.
• good permeability for water (against waterlogging)
• free from fungal spores and diseases
• free from weed seeds

Since normal potting soil always contains a fertiliser, you should use nutrient-poor substrates when growing giant lilies. Potting soil, cactus soil and coconut hum (made from coconut fibres) are well suited.

cultivation

When the seeds have germinated, the temperature can be increased slightly. The young plants are best placed in a bright location at around 15-18 degrees. If the sun shines directly on the plants, especially through a pane of glass, very high temperatures can easily occur locally. This quickly leads to burns or drying out of the still very sensitive Cardiocrinum giganteum. If the seedling has grown a few centimeters, you can remove the glass pane or foil. However, the substrate should still be kept moist. Waterlogging, on the other hand, promotes the formation of mold and often results in the young plant rotting.

• Leave plants in the pot for the first two years.
• Water and fertilize regularly.
• If necessary, repot into larger containers.
• Substrate: humus potting soil, containing sand
• Overwinter in the pot: Cold (5-10 degrees) and frost-free
• Do not plant outside until the third year.

Vegetative propagation

In addition to the usual distribution via seeds, giant lilies can also reproduce vegetatively. In contrast to propagation by pollination and seeds, absolutely identical offspring of the mother plant are produced here. After flowering, the Cardiocrinum giganteum dies and forms up to five daughter bulbs in the ground. These can be taken out and transplanted or left in place. They will sprout again next spring and will bloom again in the next three to five years. These daughter bulbs of various hybrids are often commercially available.

• Time: In the spring outdoors (May, after the Ice Saints)
• Planting depth: About 10 centimeters depending on bulb size (cover only a little with soil)
• Planting distance: half the growth height, depending on the species between 30 and 80 centimeters

wintering

Giant lilies are perennial and usually extremely frost-resistant plants. However, some species are sensitive to constant changes between frost and thaw. A dense cover of leaves (at least 20 centimeters) can protect here, which should be fixed with a basket or a grid. In the spring, the grid or basket is then removed. The foliage should remain in place until May to protect the early shoots from late night frosts. In very cold climates you can also dig up the plant and overwinter in a 10 to 15 liter bucket in a cool but frost-free place.

diseases and pests

Giant lilies are real snail magnets. Anyone who discovers the first signs of eating marks on the plant should definitely spread slug pellets generously. Otherwise, the plants are very robust and resilient.