Alstroemeria / Peruvian Lily / Lily of the Incas

Alstroemeria (syn. Alstremeria), commonly called the Peruvian Lily or Lily of the Incas, is a South American genus of about 50 species of flowering plants. Almost all of the species are restricted to one of two distinct centers of diversity, one in central Chile, the other in eastern Brazil. Species of Alstroemeria from Chile are winter-growing plants while those of Brazil are summer-growing. All are long-lived perennials except A. (Taltalia) graminea, a diminutive annual from the Atacama Desert of Chile. A very long flowering period, copious blossoms and many striking flower colors – is making the Alstroemeria assortment extremely suited as a garden and patio plant (perennial).
Perhaps the most fascinating- and telltale- morphological trait of Alstroemeria and its relatives is the fact that the leaves are resupinate, that is, they twist from the base so that what appears to be the upper leaf surface is in fact the lower leaf surface. This very unusual botanical feature is easily observed in the leaves on cut flowers from the florist.
The flower, which resembles a miniature lily, is very popular for bouquets and flower arrangements in the commercial cut flower trade. They have a vase life of about two weeks. They grow two to three feet tall on strong, branched stems. Each trumpet-shaped flower is an inch or two in diameter. Flowers come in pink, rose, purple, yellow, cream, orange, and white and are spotted or streaked with contrasting colors.
Provide a sunny location in areas with cool summers, but in hot summer regions, plant in shade. The roots must be well below the surface of the soil or the plants will not last long. Enrich soil with compost and manure. If soil is not well drained, or if you live in a cold climate where plants are not hardy, grow them in pots in well-drained soil. Store the root-filled pots indoors in a moderately cool but not freezing place for winter, and set them outside again in spring after the danger of frost passes. Some Alstroemeria species can be a little frost tender, but this can be managed by insulating the roots with mulch. Tubers are usually planted in March or April, either singly or as groups of three or five, about 20cm (8in) deep. If growing in an alpine house, grow in a mix of loam, leaf mould and sharp sand. Water while they are growing and apply a balanced fertilizer.
If the soil temperature rises too high (above about 22 degrees Celsius) the Alstroemeria plant puts its effort into producing more large tuberous roots at the expense of flowering shoots. With some varieties this can lead to production of exclusively blind non flowering stems and no flowers.
Plants will require staking each year using either stakes and netting, or twiggy pea sticks. After flowering dead head the plants unless seed is required, otherwise seedlings will appear. Cut down old stems during the autumn and protect crowns in cold winters with a dry mulch, like straw or bracken. Left undisturbed established clumps will spread freely by means of fleshy roots.
Some species are classed as weeds in some parts of the world. This is an extremely invasive species. It is definitely ill behaved in cultivation. It self-seeds vigorously unless the flowers are cut off after blooming. Neglect deadheading or move a few tubers around in the soil and it will spread throughout your garden and haunt you forever.
Care should be exercised when handling cut stems, as the sap can cause skin irritations.