Coming from a wide range of habitats in the northern hemisphere, including wetlands in Florida and alpine conditions in the Himalayas, lilies are a varied group of plants and as one would expect have varied cultural requirements. However, the vast majority of those which are common in cultivation do share some basic needs such as a lightish, friable and neutral or slightly acidic soil; adequate moisture during the growing season, a cool root run and, above all, good drainage. Lilies will not last long in a cold, wet clay soil but there are several methods which can be employed to ensure their successful cultivation in any garden. They are such beautiful subjects, many with wonderful scent, that they are well worth taking a little extra care over.
The soil can be improved to make it more suitable for lilies by digging in humus, in the form of leaf mould or garden compost, to promote water retention in hot weather and coarse sharp sand or grit to create better drainage. If your soil is very unsuitable for some reason then almost all lilies do well in raised beds where they can be provided with a specially-mixed compost and excellent drainage. Many also take happily to pot cultivation, especially if the pots themselves can be shaded (perhaps by grouping them with pots of other summer plants such as pelargoniums) in order to keep the roots cool.
Growing in the Ground
Provided that your soil is in reasonable condition and that waterlogging is not a potential problem then there are a few species and hybrids which can do well in an ordinary border. These include:
and the beautifully scented Lilium regale var. album
In general lilies enjoy a sunny position as long as their roots are shaded by neighbouring plants. Try to ensure that these neighbours are not too vigorous or spreading as the lilies may not compete well with very strong growers like, for example, paeonies. Smaller species can be excellent additions to the rock garden and as lilies do not enjoy windy positions many will enjoy the cool and sheltered conditions of the woodland garden. This is provided that the shade is not too heavy and that they receive some direct sunshine for part of the day. Many do especially well in the sheltered conditions in gaps between rhododendrons, enjoying the same cool leafy soils.
Lilium martagon enjoying a light woodland situation.
On a limey soil your choice of species may be restricted but L. candidum (the beautiful Madonna Lily), L. henryii and a few others can put on a good show.
The best time to plant lilies is in late summer or early autumn as this allows them time to establish some new roots before the winter. Unfortunately it can be difficult to obtain bulbs from commercial suppliers at this time of year which is one reason that growing one’s own stock from seed is a good idea. Bulbs with few or no roots planted into a cold and wet winter soil are very likely to rot and never appear in the spring. If the bulbs arrive in the colder months then they are best potted and kept in a cool but frost-free place and can then be carefully planted out in the spring or the following autumn.
Assuming that the bulbs are healthy and available at the correct time and that your soil is in a suitable condition then planting is very straightforward. First a hole of an appropriate size is excavated and a layer of old crocks or stones placed in the bottom.
Then a dressing of coarse grit is added.
Now the new bulbs or, as in this case, the previously potted bulbs are placed in the hole. Take care not to damage any roots. Many lilies produce masses of stem roots from the stem above the bulb and so need fairly deep planting to allow for this. The exact depth depends on the quality of your soil and its drainage but in general a depth equivalent to about two or three times the height of the bulb is correct. The bulbs will be deeper when enriching mulches are added. A notable exception is L. candidum which needs to be planted much more shallowly with the nose of the bulb only just below the surface.
Next carefully return the soil to the hole and firm it gently. Water to help the soil settle around the roots, and label. It is very important that you mark the position of the bulbs clearly so as to avoid accidental damage when working on the bed. Spring shoots are easily cut through with a sharp hoe!
A word of warning – do not be tempted to plant in a poorly-prepared soil. If you just dig a hole in an unimproved clay soil the crocks and grit will be completely ineffective and water will collect in the sump you have constructed resulting in the certain death of the bulbs! The soil and drainage of the whole area needs to be improved not just the immediate hole.
It is a good idea to try to protect the newly-planted bulbs from excess rain in their first winter and this is easily achieved by covering the planting spot with a cloche, a sheet of plastic or even a large pot. Make sure that the cover will not blow away in any winter storms. If you live in a very high rainfall area or you grow some of the more challenging species it may be a good idea to do this each winter.
These covers will need to be removed in late winter before the new shoots begin to emerge and this is a good time to feed with a little blood, fish and bone or a similar fertilizer and to apply a mulch of leaf mould.
Generally lilies hate wet feet. On the other hand some watering may be needed during prolonged hot and dry spells, especially if you live in a particularly dry area. Try not to splash the foliage as damp leaves and stems can lead to various fungal problems, some species, such as L. parvum and L. papilliferum, being more prone than others. If you experience heavy rainfall in your area then try to avoid these. Some enthusiasts resort to growing their precious and rare lilies under cover, but with excellent ventilation, not to keep them warm but to protect them from excessive rain.
Most lilies have no other special cultural requirements, simply take care of them as you would any other plants in your garden – control weeds, look out for pests (especially slugs and snails which love emerging lily shoots in the spring) and take time to enjoy what these wonderful plants have to offer.
Lilium superbum making a fine show in the open garden.
Growing In Pots
Many lilies take extremely well to growing in pots, among the species L. speciosum is a good example.
Growing them in this way has several advantages which include being able to bring them into the house or conservatory to enjoy the flowers and in this case their superb scent.
The main problems of pot culture are that it is more demanding of time and requires some skill to get watering and feeding correct. It is very important that excellent drainage is maintained so it is a good idea to raise the pots off of the ground using pot feet, bricks or pieces of paving stone.
The main principles of lily cultivation apply to pot culture in exactly the same way as growing them in the open garden; an open well-drained compost, adequate water and cool roots. Clay or plastic pots can be used successfully. Clay pots tend to keep the roots cooler and help to avoid excess water in the compost because a certain amount evaporates through the sides of the pot but they are considerably heavier than plastic. Whichever you choose the potting technique and aftercare are much the same although you may decide to use a more freely draining compost in plastic pots in order to avoid waterlogging, especially if you tend to be a little enthusiastic with the watering!
First you need to select a suitable size of pot for the bulbs you have. It needs to allow for a little growth and, hopefully, increase but over-potting is a big mistake. Lilies in the garden do best when associated with other plants, the roots of which help to take up excess water, and the soil itself contains a whole community of fungi and other micro-organisms which aid the maintenance of balanced and healthy conditions. Surrounding the bulbs with soggy compost spells disaster and so it is better to under-pot. If once the lilies are growing away it is felt that they need more room it is not a difficult task to move them on into a larger container. Having chosen a pot the next thing to do is to place a layer of crocks in the bottom.
Then a dressing of coarse grit is added.
Now you need to add a layer of your chosen compost. A good general compost consists of three parts ericaceous compost: one part coarse grit and just a little perlite. You can add a little slow release fertilizer but many growers prefer to follow a program of liquid feeding through the season, starting with a general feed and then changing to a high potash one for the second half of the growing period. Lilies such as L. speciosum and L. auratum do well in this kind of compost but it can easily be adapted to the special needs of any particular species, for example lime might be added for L. henryii or loam for those species which enjoy a slightly less humus-rich growing medium such as L. bulbiferum.
You are now ready to place the bulbs in the pot. First inspect them and remove any obviously rotten scales or roots, any serious wounds can be dusted with sulphur which may help to prevent further rotting, and then space the bulbs out on the layer of compost. Try to spread out any healthy roots without damaging them.
All that remains to be done is to fill the pot to near the rim, leaving enough room for watering, and to water and label it.
If it is autumn or winter then allow the pot to drain and dry out a little so that it is just nicely moist. You can use a finger to carefully check this.
Then seal the pot in a suitable plastic bag (a twenty litre swingtop bin liner is about right for a 20cm pot). In this way the compost will be kept at a consistently moderate moisture level and the bulbs will have a good chance to establish a basal root system before top growth begins in the spring. The pot should be placed in a dry frost-free place such as a shed or garage.
This is also a good way to store potted plants every winter.
In early spring, before top growth is evident, remove the plastic bag and place the pot in a sheltered position. Make sure to keep the bag to use again. It is especially important not to over-water whilst the new bulbs have few roots and to check the pot regularly. Once growth is well under way watering can be carefully increased and then liquid feeding can begin when you feel confident that a good root system has been developed.
All photographs are copyright © Mel Herbert.