Commonly known as ‘Peruvian Lily’
Alstroemeria are much hardier and easier to grow outside than many people realise. With such colourful and exotic flowers there is a temptation to regard them as tender greenhouse plants especially when viewing displays of cut flowers at the Chelsea Flower Show.
Peruvian lilies have fleshy tubers which quickly spread to form clumps in the garden. Handle the tubers with care and gloves as they can cause skin allergies or rashes especially if you break the tubers and white sap emerges. The tubers need to be planted at least 8in deep preferably in late summer or early autumn when they die down and go dormant.
Nearly all alstroemeria will then withstand -10°C. The taller growing A. ligtu hybrids which can have a multitude of different colours, but, in original form, are deep yellow, can withstand -15°C of frost. It helps however if they have a good leafy mulch or peat mulch over the top of them for the winter. They will have flower stalks of 2ft or more.
They flower best in full sun or partial shade in fertile and reasonably well drained soil. Some of the clumps at Caerhays have flourished for generations with little attention.
Slug and snail damage can be a real threat in April as the leaves and new shoots develop. This can inhibit flowering and preventative treatment should be in place. This is especially true of the more dwarf growing (12in) ‘Princess’ varieties.
Alstroemeria varieties flower away from May to November but are generally at their best in July or August.
At the end of the season you may find that some flower spikes have developed poppy-like light brown seed heads. These will contain many seeds which can be dry stored over winter and sown in spring in containers. You can sow in autumn in a frost free greenhouse. If you grow several varieties of alstroemeria do not expect the end result to be anything but a mixture. The best bet is therefore to very carefully lift and split the tubers in the autumn from already named varieties.
