Alstroemeria aka Lily Of The Incas

Alstroemeria is drought tolerant once established but benefits from regular watering during dry periods and the growing season. Water when the top inch of soil feels dry, typically once weekly during active growth. The most critical point is to avoid overwatering, as soggy soil can cause root rot. Ensure excellent drainage and allow soil to dry slightly between waterings. Container-grown plants need more frequent watering as compost dries quickly, especially in summer.

Alstroemeria thrives in fertile, well-drained soil enriched with organic matter like compost or well-rotted manure. The ideal pH is slightly acidic to neutral (6.0-7.0). Avoid heavy clay soils that retain water, as good drainage is essential to prevent root rot. The plants perform well in beds where rhododendrons and camellias thrive, indicating their preference for similar acidic conditions.

Alstroemeria tolerates average outdoor humidity levels and doesn't require special humidity considerations when grown in its typical garden setting. However, good air circulation is important to prevent fungal diseases like botrytis (gray mold), which can develop in overly humid, stagnant conditions. In areas with high humidity, ensure adequate spacing between plants to promote airflow and avoid overhead watering that keeps foliage wet.

Alstroemeria are heavy feeders that benefit from regular fertilization during the growing season. Apply a balanced, slow-release fertilizer in spring to jumpstart growth. Throughout summer, feed weekly with a high-potash fertilizer like tomato feed to encourage abundant flowering. Reduce feeding in autumn as the plant prepares for dormancy.

Division of rhizomes is the most reliable and easiest propagation method for Alstroemeria. Divide established clumps in spring (April) or autumn by carefully lifting the plant and separating sections that include 3-5 growing points with attached roots. Handle the fragile roots gently and replant divisions immediately at 15-20cm depth. A one-year-old plant can yield up to 15 rhizomes, while a two-year-old may produce 25. Seed propagation is possible but challenging, with only about 20% germination rate and several years before flowering.

Alstroemeria typically reaches 60-90cm (2-3 feet) in height with a spread of 45-60cm, though this varies considerably by variety. Compact cultivars like the Princess and Inticancha series stay at 25-35cm, while taller varieties can reach up to 1.5m. Plants grow from spreading rhizomes and form gradually expanding clumps over 2-5 years to reach mature size. Growth is moderate, not aggressive, and clumps increase steadily rather than rapidly. Most varieties benefit from staking or support as stems can be quite tall.

Alstroemeria is native to South America, with two distinct centers of diversity: central Chile and eastern Brazil. The genus extends from southern Venezuela through to southern South America, including Argentina, Bolivia, Peru, Paraguay, and Uruguay. Chilean species are winter-growing while Brazilian species are summer-growing. The plants grow naturally in various habitats from dry scrub in rocky sandy soils to cerrado and pantanal vegetation. They have been introduced and naturalized in regions including parts of the United States, New Zealand, Australia, and Europe.

Alstroemeria produces clusters of funnel-shaped flowers atop slender, erect stems from early summer through autumn (June to October), providing an exceptionally long flowering season. Flowers come in a wide range of colors including red, orange, yellow, pink, purple, and white, often with distinctive streaking or spotting patterns. Each bloom resembles a small lily with six tepals, the upper ones typically marked with contrasting stripes. The flowers make excellent long-lasting cut flowers, staying fresh in vases for up to two weeks.

Alstroemeria is pollinated primarily by insects, especially bees and butterflies, attracted to the colorful flowers with distinctive nectar guide patterns. Honey bees are frequent visitors, and the flowers also attract hummingbirds. The plants employ a mechanism called dichogamy, where male and female parts mature at different times to promote cross-pollination and reduce self-fertilization. The brightly colored petals and contrasting markings serve as visual guides directing pollinators to the nectar and pollen.

Alstroemeria is primarily an outdoor garden plant, thriving in USDA zones 7-10 and hardy to zone 6 with winter protection. In zones 7-10, plants can remain in the ground year-round. In zone 6 and colder areas, apply 15-20cm of mulch (straw or shredded leaves) after first frost to insulate roots. In zones colder than 6, treat as tender perennials by lifting and storing rhizomes in dry peat moss over winter, or grow in containers that can be moved to frost-free locations.

Alstroemeria requires minimal pruning. The key technique is deadheading spent flower stems by pulling the entire stem gently from the base rather than cutting it. Grasp near the base and pull upward with a gentle tugging motion. This method encourages new stem production and extends the flowering season. In early spring before new growth appears, remove any remaining old stems. Avoid cutting live stems during the growing season as this can weaken the plant. The pulling technique is unique to Alstroemeria and produces better results than traditional cutting.

Container-grown Alstroemeria benefits from repotting every 2-3 years in spring when roots become congested. Choose a container at least 30cm deep to accommodate the deep-growing rhizomes. Use well-draining potting mix with added grit or perlite. When repotting, this is an ideal time to divide overcrowded clumps. Handle the fragile roots carefully and replant at the same depth. Newly potted divisions should be kept moist but not waterlogged until established. Container plants dry out faster than ground-planted ones, requiring more frequent watering and feeding.

Alstroemeria thrives in moderate temperatures, ideally between 15-25°C (59-77°F) during the growing season. Most varieties tolerate winter temperatures down to -10°C (14°F) when properly mulched and established. Young plants are more vulnerable to cold in their first two winters, so provide extra protection. Hot temperatures above 30°C can cause flowering to slow. In very cold climates (below zone 6), roots should be lifted and stored in frost-free conditions.

Common pests include thrips, aphids, spider mites, slugs, and snails, though plants are generally resistant to mammal browsing due to mildly toxic foliage. Aphids can be controlled with strong water sprays or insecticidal soap. In overly wet conditions, botrytis (gray mold) may develop, especially in humid, poorly ventilated areas. Pythium root rot occurs in waterlogged soils, causing stunted growth and wilted stems. Good drainage, adequate spacing for air circulation, and avoiding overhead watering help prevent fungal issues. The plants are generally low-maintenance once proper growing conditions are established.

Popular Alstroemeria series include the Princess Series (compact at 25-35cm, ideal for containers, featuring Princess Fabiana, Princess Kate, Princess Diana), the Inca Series (medium to tall with large blooms, excellent for cutting, including Inca Ice, Inca Glow, Inca Lake), and the Inticancha Series (compact, vivid colors, container-friendly). Taller traditional varieties reach 60-90cm and are excellent for garden borders and cut flowers. Modern breeding has produced more compact, less invasive cultivars compared to older varieties. Choose based on your space: compact series for pots and small gardens, taller varieties for borders and cut flower production.

The tuberous roots of Alstroemeria are edible when cooked, providing a nutritious starch similar to potatoes. In Chile, these roots are traditionally sold in local markets and prepared as a food source, particularly for children and convalescents due to their digestibility and nutritional value. However, the leaves and flowers contain mild toxins that can cause digestive upset if ingested, and the plant sap can cause contact dermatitis. Never consume raw roots or any above-ground parts. This is primarily relevant to wild species; ornamental garden varieties are typically grown for flowers rather than food.

Alstroemeria is primarily valued as an exceptional cut flower, with blooms lasting up to two weeks in vases, making it one of the most popular commercial flowers worldwide. The flowers come in a stunning array of colors and are widely used in bouquets, floral arrangements, and wedding decorations. In gardens, they attract pollinators including bees, butterflies, and hummingbirds, supporting biodiversity. The plants make excellent border perennials and container specimens. Historically, indigenous peoples in South America used the roots as a food source, though this practice is less common today.