Lillium

Common name: Lily

There are over 80 species of lily and thousands of hybrids.

For reference purposes;

They have been classified into 9 divisions and sub-divisions in relation to their origin and flower type, these are;

Div 1

Asiatic hybrids.

Div 2

Martagon hybrids.

Div 3

Candidum hybrids.



Div 4

American hybrids.

 
Div 5
Longiflorum hybrids.
Div 6- Trumpet &
Aurelian hybrids.


Div 7
Oriental hybrid

 

Div 8
Hybrids not belonging
to any other division

 

Div 9
All true species and
their botanical forms

 



Overview:

Lilies come in many colours,shapes and sizes, plus hybridisation has made many varieties more tolerant to conditions outside their place of origin, thus making them easier to grow!

They make excellent cut flowers, and can be grown in borders, amongst shrubs, or in tubs.

Depending upon variety they will grow to 500-1000 mm (20"-40") in height and flower from June to September in the UK.

Lilies need a well-drained position, but often do not survive the competition experienced in herbaceous borders.

To alleviate this problem they can be grown in suitable sizes pots and placed where needed when in flower.

This method is useful when there is a need to fill a spot in the border that is bare after a plant has died back or has been removed.

Cultivation in Borders:

Always buy fresh bulbs and plant them upon arrival, they resent being allowed to dry out.

Do not buy shriveled bulbs!

If when the bulbs arrive, and the ground is unworkable, store them in a mixture of sand and peat in a cool position until ready for planting out (Week 20) alternatively; between weeks 40-45.

Be extra careful when transplanting/handling the bulbs at this stage, the brittle roots are easily damaged.

The plants prefer a cool, semi-shaded area where the soil is well-drained, yet not prone to drying out in summer.

In general a neutral soil with a pH of around 6.5 is ideal.

Prior to planting out, the soil should be enriched with well rotted manure or garden compost, or leaf mould if available.

Heavy soils should have plenty of coarse sand and grit worked in.

Plant the bulbs with a covering of soil equal to three times the height of the bulb.

If this is impractical because of insufficient soil depth, plant them 150mm (6") deep and 250mm (10") apart.

In shallow soils there is an increased possibility of wind rock so it is advisable to insert a cane at this stage for eventual support.

To do this later may result in damage to the bulb.

Place the bulb on a layer of coarse grit to prevent the bulb becoming waterlogged.

After planting mulch with well rotted manure or garden compost, or leaf mould if available, this should be repeated annually in the spring.

Protect emerging shoots from slugs. (Week 5)

Circa Week 23: keep a look out for red lily beetle.

Some taller varieties of lily may require support.(see note above)

Remove flower heads after flowering.

Lilies resent being disturbed so they should he left for 3-5 years.

They can be lifted and divided in late summer when the foliage has started to die down.

Cultivation in Containers:

Lilies are best potted up in autumn (Week 40-45) although bulbs can be planted as late as spring (Week 5-13)

For effect, plant 3 bulbs into a 200-250mm (8”-10”) pots, ensuring that there is a generous drainage layer of coarse gravel or crocks in the bottom of the pot.

A free draining, lime-free, compost is recommended.

Loam based compost is preferable to peat based composts, as this retains moisture better.

Lilies are heavy feeders, so add a slow release fertiliser when planting.

When planting the bulbs they must be at least 75mm (3") apart and 50mm (2") away from the side of the container.

Basal rooting lilies should be planted at a depth equal to the height of the bulb!

Follow this procedure for varieties whose habit is unknown.

Stem rooting lilies should be planted at a depth roughly two-and-a-half times the height of the bulb.

Some varieties root from the base of the bulb, e.g. asiatics whereas, others such as longiflorum, produce roots from the stem at a point just above the bulb. so it is better to plant these varieties out in a deeper pot.

Alternatively, lay a mulch of compost around the stems of established potted lilies, and this will allow these varieties to send out roots into the mulch resulting in greater stability and a better intake of nutrients.

After potting, ensure that the compost is kept moist but never waterlogged.

If the weather is inclement the container may be stored in a cold frame, cold greenhouse or by plunging the pot in the soil.

Otherwise, put them into position where the tub/pot is shaded, to avoid the roots becoming overheated.

Circa Week 23: If not done previously, stake taller varieties.

Aftercare:

In some parts of the UK it may be necessary to protect against frost.

In the colder areas protect the pots with bubble polythene.

Protect emerging shoots from slugs.

If forcing, fetch the pots indoors when the first flower buds show colour and place them in a sunny position.

When in growth, water freely and apply a high-potassium liquid feed every two weeks.

The flowers will last longer if the roots are cool, it is important that they are frequently watered when in flower.

After flowering, deadhead and liquid feed.

Container grown lilies usually need annual re-potting to ensure prolific flowering the following year.

This should be done around Week 40-45.

Alternatively, as the stems begin to wither transfer bulbs to the garden,ensuring you remove the old stem/s and roots prior to replanting.

In larger containers lilies can be grown on for a second season, but ensure that the top 50mm (2”) of compost is replaced with fresh compost.

Propagation:

Most lilies increase vegetatively by producing bulb offsets, if greater quantities are required these can be split from the parent plant and replanted.

To further increase quantities there are other techniques that can be used to speed up this process, e.g. scaling, bulbils, or seed.

Always propagate from healthy stock.

Scaling:

Week 13: Now is an ideal time to propagate lilies by means of scaling.

The method is as follows;

Select the bulb/s you wish to propagate from, and remove and discard any damaged scales.

Carefully snap off a few scales from the bulb as close as is possible to the base of the bulb so that they retain a small piece of basal tissue.

Disinfect / protect scales with a general fungicidal powder.

A simple way to do this is to place some powder in a plastic bag then add the scales.

Gently shake the bag to cover the scales with powder.

Prepare another plastic bag by placing a mixture of peat and perlite (ratio 50-50) into it.

Title and date the bag for future reference!

Place the prepared scales into the bag, inflate the bag by blowing into it then seal it with a twist tie!

Place the bag in a warm place circa 21°C (70°F) for three months, then move it into a refrigerator (not a freezer) for 1½-2 months, or until you see small bulblets forming on the scales.

These bulblets should be removed from the scales as it is these that will be potted on.

Great care must be taken at this stage not to damage the bulblets when removing them from the scales.

Soft bulblets will normally part from the scales quite easily, however if any resistance is met with this procedure, leave the bulblets attached to the scale/s and pot up both.

The bulblets can be planted singly12mm (½”) deep into 50-70mm (2”-3”) pot/s filled with a proprietary potting compost or about 50mm (2”) apart in a tray.

Cover the bulblets with grit and leave them in a warm (frost free) well lit place to develop until next spring (circa Week 13/14), when they can be transfered into trays/pots and placed in a cold frame.

Circa week 40 separate those those are being grown in trays and those in small pots into 100mm (4”) pots and store in cold frame till planting out time.

A variation on this technique is that when you are lifting / transplanting bulbs from beds/containers you may notice that small bulblets have formed around the main bulb.

These can be picked off and grown on as described above i.e. from the stage where the bulblets were removed from the scales.

Bulbils:

Week 39: Some varieties can be readily increased by means of tiny bulbs (bulbils) that develop in the leaf axils.

Week 40: Ripe bulbils part readily from the stems and should be sown in well-drained compost.

Space them about 25mm (1”) on the surface of the compost until there are signs of rooting then cover with 12mm (½”) of compost.

Prior to covering remove any that have rotted or failed to root.

Week 42: When the seed leaf is 75-100mm (3”-4”) long, pot them up singly into 75mm (3”) pots and grow on in a cold frame.

Bulbils on the plant

Bulbils on the Compost

Potted up


The following spring plant them out into a nursery bed to mature to flowering size.

Then the following spring after that, plant out into their final quarters.


Seed;

Lilium raised from seed will not come true to the parent plant, however, this attribute creates the potential for producing some exciting new plant varieties.

Collect seed when the pods, which follow the flowers, have ripened and the seed pod has started to split.

Week 34: Sow the ripe seed immediately after collection into small pots containing proprietary seed compost, top-dress the compost with coarse grit, water in thoroughly, add a dated label, and place in a cold frame to germinate.

Alternatively, delay the sowings to the following spring.

Some lilies can take two to six weeks to germinate after sowing.

Others may take several months.

Leave the germinated seedlings in their containers for their first growing season and give them liquid fertilizer regularly.

Alternatively, prick them out when they have two true leaves into loam-based potting compost.

Repot them regularly or transfer them to nursery beds until they are large enough to be planted out in the garden.

It can take up to three years for the bulbs to reach flowering size.

Regal lilies: require a different technique, this is known as the Folder technique which is as follows;

Week 13: Sow seed at least 5mm apart on a piece of kitchen towel then moisten the paper lightly with a hand spray.

Fold the kitchen towel in half and place it in a polythene zip bag and place in a position out of direct sunlight and at a temperature of 20°C (68°F).

Check daily for results.

Signs of germination will become apparent when the roots will become visible when they appear through the paper wrapper.

The seedlings should then be allowed to develop for around two weeks.

Transfer the chitted seed into a tray of seed compost and cover with fine grit or sandy compost.

You may find that as you remove the seedling from the paper some of the roots have become entangled in the paper in cases such as these, it is safer to cut the paper at this point rather than damaging the brittle roots trying to extricate them.

Place the seedlings in cool greenhouse or coldframe to grow on.

Ensure they do not dry out!

Misting the surface of the compost regularly should alleviate this problem.

Do not disturb the seedlings until they are of a size that can be transplanted into 70mm (3") pots.

It will probably take up to three years for the bulbs to reach flowering size.

Grow the seedlings on in the seed tray for the whole season and place in a frost-free environment over winter.

Pests and diseases:

Lilies are particularly vulnerable to viruses transmitted by aphids.

Some varieties are more susceptible than others.

Those that become affected should be kept away from other varieties to prevent infection spreading, and some means of aphid control should be introduced.

Affected bulbs/plants should lifted be destroyed.

Grey mould (Botrytis) can be another problem.

This is often prevalent in damp sheltered areas where drainage and air circulation is poor.

These damp conditions can also encourage basal rot.

Red lily beetle can decimate foliage and flower.





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