Growing Lilies in Pots
In the cold bleak months of January and February ordering bulbs and seeds is a pleasant task that leads us forwards to sunnier times.
Lilies make sumptuous, extravagant additions to the garden. They have a heady fragrance and perform well in pots which can be moved around for maximum impact. They are rewarding and easy to grow.
First select a pot. This will need to be deep because the bulbs should have twice their height of compost above them. Three bulbs in one pot make a good display, but make sure there is at least 5cm between the bulbs. Use a good quality all purpose compost which is free-draining. Lilies do not like soggy soil and are prone to rot if too wet. You can add some slow-release fertiliser to the compost if you like. The bulbs should be planted by the end of March so there is time for good root development, but they can also be planted in the autumn provided they are not allowed to become waterlogged over the winter. Lilies are greedy plants and will need regular feeding and watering throughout the growing season. Liquid seaweed or tomato food every couple of weeks is ideal. Deadhead once when flowering is over. Because all the lily’s leaves are along the flowering stem, only the top is removed so photosynthesis can continue, and the bulb is replenished for flowering in subsequent years. If your best pots are currently full of spring flowering bulbs consider planting the lilies in a plastic pot which can be dropped in when the current occupants are over.
Lilies only flower once in the year but you can extend the season of interest by combining other plants in the same pot. The photos below show two suggestions. First is a pink Thunbergia using stems of Lilium regale as a climbing frame. The second, taken in October, shows Spanish Flag (Ipomoea lobata) climbing up stems of Lilium ‘African Queen’.
These combinations have provided colour for five months from June to October. Combining lilies with other plants has the added advantage of making sure the bulbs get fed and watered, and not forgotten in a corner once they have finished. Selecting a mixture of varieties with different flowering periods will also help. The asiatic lilies flower before the oriental varieties. Personal tried and tested favourites are Lilium regale AGM and L ‘African Queen’ AGM (pictured below) and L ‘Casablanca’ AGM, flowering in that order. Casablanca has massive wide open white flowers with knockout scent. Tree lilies, or Orienpet lilies, are crosses between asiatic and oriental lilies with the best qualities of both. They will get tall but may take several years to reach their ultimate height. Their height means they are top heavy so they need a solid pot to avoid blowing over.
Unfortunately there is a nasty pest which can spoil your lilies - lily beetle. These little blighters are scarlet. They attack lilies and fritillaries, eating the leaves and munching the flower buds which are then distorted and damaged when the flower opens. Their pupae overwinter in the soil, emerging in spring to climb the stems, feed and breed. Keep an eye on your fritillaries which start to flower first, and can give you advance warning of trouble to come. The good news is that the beetles are easy to spot. Usually the first sign of their presence is leaves with holes, and deposits of sticky brown frass (droppings) under the leaves. The beetles need to be removed and squashed on a regular basis. The frass also needs to be removed because the developing beetle larvae hide within it. The least unpleasant way to do this is to simply remove the leaf with frass underneath. Asiatic lilies are the most vulnerable, while some species of oriental lilies have a degree of resistance. Lilium speciosum ‘Uchida’ and Lilium ‘Black Beauty’ are relatively unattractive to the beetles, but they are best grown in the ground, not pots.
Lily beetles are interesting creatures with unusual defence mechanisms. When they sense impending attack they tuck in their legs and fall to the ground upside down concealing their red backs to hide from predators. They can also make a squeak (stridulation) to startle and deter an attacker.
Cat lovers will probably know that lilies are toxic to cats. All parts of the lily are poisonous, and can cause irreversible kidney damage, even death, if sufficient is ingested and treatment not started promptly. The biggest risk is probably from accidental ingestion of pollen which may get onto the cat’s fur and be licked off through grooming. There are several steps you can take to reduce this risk. The stamens which bear pollen can be snipped off, in growing blooms or cut flowers. You can choose lilies which have been bred to be pollen-free, and avoid the shorter stemmed varieties which are more likely to transfer pollen onto a cat. If you have lilies in a vase, make sure the water is not accessible for cats to drink.
The risk of lily poisoning needs to be kept in perspective. Lilies are not the only plants which are toxic to cats. In 2022 the Horticultural Trades Association, in conjunction with the Veterinary Poisons Information Service, upgraded its Guide to Potentially Harmful Plants. Link here: https://hta.org.uk/poisonousplants . You will see that many common garden plants are poisonous to cats (and dogs) if eaten, including snowdrops and agapanthus. Cats have co-existed with these plants for years and while you may decide not to risk growing lilies, your cat may wander into neighbouring gardens where lilies and other potentially toxic plants are growing.