- Lilies and Liliaceae
- Overwintering lilies in the garden properly
- Overwintering lilies in pots properly
- Frost-free overwintering of the lily bulbs
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When the leaves on the trees start to change colour, autumn is fast approaching. Now it's time to winterize the garden. Many typical garden plants easily survive the cold season outdoors. But what about the different types of lilies? Do they survive frost and moisture or do they have to be dug up and overwintered frost-free? How hardy are the common Lilium species really?
Lilies and Liliaceae
Risk of confusion: Not every lily is actually a lily family
Not everywhere, where a "lily" is hidden in the name, it is actually a lily plant. Both the day lily (Hemerocallis), the belladonna lily (Amaryllis belladonna) and the Jacob's lily (Sprekelia formosissima) do not belong to the lily family. Real lilies can be recognized by their botanical name "Lilium". Nevertheless, we will also explain to you at this point about the actual winter hardiness of the "wrong" lilies:
- Daylilies: hardy to - 15 °C or - 20 °C, depending on the variety
- Belladonna lily / true amaryllis: sensitive to frost, hibernate frost-free at 10 to 15 °C
- Jacob's lily: sensitive to frost, frost-free, winter dry and dark at about 15 °C
- Toad lily / tiger star: Tricyrtis hirta, hardy to -20 °C for a short time, thick layer of mulch protects against frostbite
yellow-red daylily
Hardy Lilium hybrids
Only a few decades ago, real lilies were considered extremely capricious. Many species, although mostly native to the northern hemisphere, were not sufficiently hardy for most regions in Germany. They had to be dug up in the fall and overwintered frost-free.
Nowadays, however, robust, easy-care and hardy hybrids are available in garden centers and specialist shops. These are hybrids of different types of lilies, which were then not only selected for their beauty, but also for other desirable properties such as winter hardiness. Therefore, with a few exceptions, you can safely leave modern lily varieties in the garden and get them through the winter with just a few protective measures.
These lilies can stay outside in winter
The following types of lilies are particularly well prepared for the winter:
- Asiatic Lily: most common hybrid cultivar group, typically frost hardy but need some winter protection
- Oriental Lily: hybrid cultivars mostly from Japan, usually frost hardy but need light winter protection
- Turk's cap lily: native species, hardy, no special winter protection necessary
- Chinese mountain lily: belongs to the Chinese Turk's cap lilies, frost and winter hardy, light winter protection makes sense
- Trumpet Lily: Lilium longif.webplorum hybrids, frost and winter hardy with light protection
- Royal lily / White lily: Lilium regale, one of the best-known trumpet lilies, reliably frost hardy, light protection required
- Nepal Lily: Hybrid of Lilium nepalense x oriental, hardy, needs light winter protection
- Canada lily / Canadian water lily / Canadian meadow lily: Lilium canadense, native and common species in many provinces of Canada, good winter hardiness, frost hardy
- Tree lilies: very hardy, but light winter protection (mulch layer) makes sense
- Orange lily: Lilium bulbiferum, native species, occurs wild in meadows, primarily in the foothills of the Alps and in the Harz Mountains, no frost protection necessary
- Tiger Lily: Lilium lancifolium, native to East Asia, reliably frost hardy but does not tolerate winter wet conditions
- Panther Lily: Lilium pardalinum, native to western North America, winter protection (mulch layer, e.g. pine bark) useful
- Magnificent lily: Lilium spec. rubrum, adequate winter hardiness
royal lily
Not hardy lilies
These lilies are delicate
In contrast to the lily species and hybrids listed above, both the exotic Alstroemeria and the Madonna lily are not sufficiently hardy and therefore require special care during the cold season.
The Alstroemeria, which is native to the subtropics, does not survive a winter with prolonged frost, even if the plant becomes more winter hardy with age. In regions with mild winters (e.g. in wine-growing areas), the bulbs can remain in the ground, but must be covered with a thick layer of mulch. In regions with probable frost periods, on the other hand, autumnal digging and frost-free wintering are recommended.
The Madonna lily (Lilium candidum) is one of the oldest lily species. It comes from the Mediterranean region, needs a full sun and sheltered location - as well as adequate winter protection. However, well covered with brushwood and a thick layer of mulch, the bulbs can remain in the ground during the cold season.
Alstroemeria, Alstroemeria
Overwintering lilies in the garden properly
Whether it's an oriental, asiatic or other hardy lily species, most will need some light protection during the winter months. Ideally, this consists of one Cover with brushwood, for example fir or spruce branches, which are primarily intended to protect against moisture rather than frost. In many cases, the problem is not temperatures falling below zero, but wet winters. Most lilies do not tolerate moisture at all and rot. Humidity in combination with persistent frost can also be deadly for the flowers: the waterlogged bulbs can burst and be destroyed. The ideal winter protection for Lilium is therefore primarily protection against moisture and is done in this way:
- Cut yellow and brown leaves down to the ground
- withered flowers too
- Covering the root area with compost/humus
- further cover with brushwood
Overwintering lilies in pots properly
On the other hand, if the flowers are cultivated in pots, a more comprehensive protection is recommended. Since there is naturally only little soil in planters, this cannot provide sufficient frost protection. At best, help with one fleece coat after you wrap around the pot. The vessel is in turn on a insulating pad made of wood or styrofoam and pushed against a wall. Finally, cut down the above-ground parts of the plant and cover the root area with one thick layer of brushwood.
Frost-free overwintering of the lily bulbs
On the other hand, lily species that are not sufficiently winter-hardy should be dug up in autumn and overwintered frost-free. To do this, proceed as follows:
- Cut down withered inflorescences or seed heads
- Cutting down yellow or brown leaves
- Digging up the bulbs, cleaning off sticky soil
- Air dry onions for two days
- Fill a wooden box or basket with sawdust
- Store the onions in it in an airy place
- Overwinter bulbs in a dark, dry and frost-free place at 10 to 15 °C
- possible places for wintering: basement, garage, garden shed, attic
It is absolutely necessary to cut off the yellowed or withered leaves first, as the nutrients contained in the green leaves are absorbed by the bulb and needed for renewed growth in spring.