Sometimes called Peruvian lily, Alstroemeria is a flowering herbaceous plant commercially grown as a cut flower. Once in soil, Alstroemeria self-propagates through rhizomes so vigorously that it might break pots or invade other areas of your garden. Alstroemeria is native to Brazil, Chile and other regions of South America, but the species has been hybridised extensively to produce the options you find today. Grow Alstroemeria in U.S. Department of Agriculture zones 6 to 8. Rhizome clumps of different varieties are available from nurseries.
Remove weeds, grass and debris from a site receiving full sun or dappled sunlight. Select a planting area protected from the afternoon sun if your region experiences summers that push soil temperatures above 70F, which can cause Alstroemeria to cease flower production and go dormant.
Loosen the soil with a shovel and pickaxe. If your garden soil is clay, leave it undisturbed but on top, build a bed made of a blend of 70 per cent organic matter, such as compost, and 30 per cent perlite soil mix.
Dig a 2-inch-deep trench. Plant the Alstroemeria rhizomes two to three feet apart along the furrow. Refill the trenches with topsoil, covering the rhizomes until the furrows are level with the ground surface. Plant the rhizomes when the temperature is above 50F in spring or fall.
Irrigate the rhizomes at planting and keep the flowerbed moist until stalks poke through the ground. Apply an inch of water weekly to established Alstroemeria.
Build a 2-inch-deep mulch ring around the base of each plant to keep the roots cool in the summer. Use bark, wood chips, compost or other mulching material.
Feed 2-year-old and older Alstroemeria in the growing season with a high-nitrogen fertiliser that also contains phosphorous and potassium. Apply it according to the manufacturer's instructions for the brand you selected.
Clip faded flowers to encourage the Alstroemeria to produce new blooms.