Alstroemeria: Complete Guide to Growing Stunning Peruvian Lilies

Introduction to Alstroemeria: The Peruvian Lily

Alstroemeria, commonly known as Peruvian lily or lily of the Incas, is a stunning tuberous-rooted perennial that brings vibrant, long-lasting color to gardens from late spring until the first frost. These elegant flowers, with their lily-like blooms marked by distinctive speckles and streaks, have become increasingly popular among gardeners for their remarkable versatility and extended flowering period.

Native to South America, particularly the cool mountainous regions of the Andes, Alstroemeria has been extensively hybridized to create varieties suitable for different growing conditions and garden styles. Modern cultivars range from compact dwarf forms perfect for containers to taller varieties that make stellar additions to perennial borders and cutting gardens.

What makes Alstroemeria particularly appealing is their incredible bloom time—with proper deadheading, these plants will produce flowers continuously for months, making them one of the most rewarding perennials for gardeners seeking season-long color. Their flowers also make exceptional cut blooms, lasting up to two weeks in arrangements, far longer than many traditional cutting flowers.

Alstroemeria Basics

Plant Profile

Before diving into cultivation techniques, it’s helpful to understand the basic characteristics of Alstroemeria:

• Botanical name: Alstroemeria spp. and hybrids
• Common names: Peruvian lily, lily of the Incas, princess lily, parrot lily
• Plant type: Tuberous-rooted herbaceous perennial
• Hardiness zones: Typically 8-10, with some varieties hardy to zones 6 or 7 when provided extra winter protection
• Sun exposure: Full sun to part shade, with afternoon shade beneficial in very hot climates
• Height and spread: Varies significantly by cultivar, ranging from compact 8-inch dwarf varieties (often called “micro Alstroemeria”) to statuesque 4-foot specimens
• Bloom time: Late spring until frost, with continuous flowering when properly deadheaded

Site Selection and Soil Preparation

Successful Alstroemeria cultivation begins with selecting the right location and preparing proper growing conditions. These perennials have specific needs that, when met, will reward you with months of colorful blooms.

Light Requirements

Alstroemeria thrives in full sun to partial shade conditions. In most climates, these plants perform best with at least 6 hours of direct sunlight daily. However, in regions with intensely hot summers, providing afternoon shade will protect the plants from scorching and help maintain consistent blooming. The key principle to remember is that more sunlight typically results in more abundant flowering—Alstroemeria planted in too much shade will produce fewer blooms and may develop leggy growth.

Soil Conditions

The ideal soil for Alstroemeria is fertile, well-drained, and rich in organic matter. These plants will not tolerate waterlogged conditions, which can quickly lead to root rot and plant failure. Before planting, take time to improve your soil by incorporating:

• Compost or well-rotted manure to enhance fertility and soil structure
• Coarse sand or fine gravel in heavy clay soils to improve drainage
• Organic matter like leaf mold to create the slightly acidic conditions these plants prefer

The optimal soil pH for Alstroemeria ranges from slightly acidic to neutral (6.0-7.0). If your soil is significantly outside this range, consider amending it accordingly or choosing to grow your Alstroemeria in containers where you can more easily control the growing medium.

Climate Considerations

While modern Alstroemeria hybrids have been bred for increased hardiness, these plants still prefer moderate temperatures. In extremely cold regions (zones 5 and below), Alstroemeria is best treated as a container plant that can be brought indoors for winter. For gardeners in marginal zones (6-7), selecting cold-hardy varieties and providing winter protection will increase success rates.

When choosing a planting site, also consider protection from strong winds, which can damage the relatively brittle stems of taller varieties. A location with a windbreak, such as a fence, building, or larger shrubs, can help preserve the plants’ appearance and flowering ability.

Planting Alstroemeria

When to Plant

The optimal time to plant Alstroemeria is during the spring after all danger of frost has passed. This gives the plants the entire growing season to establish before winter. In milder climates (zones 8-10), fall planting is also successful, allowing root development during the cooler months before the next growing season begins.

Planting Process

Alstroemeria grows from tuberous roots that require careful handling during the planting process. Follow these steps for successful establishment:

1. Dig a hole approximately 6 to 8 inches deep and slightly wider than the root ball.
2. Gently remove the plant from its nursery container, taking care not to disturb or damage the root system.
3. Place the plant in the hole so that the soil level matches the top of the root ball.
4. Avoid teasing or spreading out the roots, even if they appear congested, as this can damage the sensitive tuberous structures.
5. Backfill with the surrounding soil, ensuring the roots are completely covered.
6. Tamp down gently to eliminate air pockets without compacting the soil.
7. Water thoroughly after planting to settle the soil around the root ball.
8. Add more soil if settling occurs after watering.

Spacing

Proper spacing is crucial for healthy Alstroemeria growth and optimal flowering. Generally, plants should be spaced 1 to 2 feet apart, depending on the mature width of your chosen variety. Dwarf varieties can be planted closer together (approximately 12 inches apart), while larger cultivars may need up to 24 inches of space between plants to allow for proper air circulation and growth.

Container Planting

Alstroemeria adapts well to container culture, making it accessible for gardeners with limited space or challenging soil conditions. When growing in containers:

• Select a pot at least 12 inches deep and wide to accommodate the tuberous root system
• Ensure the container has ample drainage holes
• Use a high-quality, well-draining potting mix, ideally one formulated for perennials
• Consider adding extra perlite or coarse sand to enhance drainage
• Position potted Alstroemeria where it will receive appropriate sunlight

Container-grown Alstroemeria will require more frequent watering and fertilization than plants grown in the ground, but they offer the advantage of mobility, allowing you to showcase the plants when in bloom and relocate them during dormancy or extreme weather conditions.

Ongoing Care and Maintenance

Watering

Alstroemeria requires consistent moisture, particularly during the growing season. While established plants have some drought tolerance, irregular watering can lead to reduced flowering and plant stress. Follow these watering guidelines:

• Water deeply but infrequently, allowing the top inch of soil to dry slightly between waterings
• Provide approximately 1-1.5 inches of water weekly, including rainfall
• Increase watering during prolonged dry spells or periods of intense heat
• Reduce watering in late fall as plants enter dormancy
• Apply water at the base of plants to keep foliage dry and prevent fungal issues

Container-grown Alstroemeria will need more frequent watering, especially during summer months. Check containers daily during hot weather, as they can dry out quickly.

Fertilization

To support continuous flowering, Alstroemeria benefits from regular fertilization throughout the growing season. A balanced approach includes:

• Applying a slow-release balanced fertilizer in early spring when new growth emerges
• Supplementing with a high-potassium (potash) liquid fertilizer, such as tomato feed, every 2-3 weeks during the flowering period
• Avoiding high-nitrogen fertilizers, which can promote lush foliage at the expense of flowers
• Discontinuing fertilization in late summer to early fall to allow plants to prepare for dormancy

Deadheading and Pruning

One of the most important aspects of Alstroemeria care is proper deadheading, which significantly extends the blooming period. Unlike many perennials, Alstroemeria should not be deadheaded by simply removing the spent flower:

Instead, remove the entire flowering stem by gently pulling it from the base with a slight twisting motion. This technique stimulates the plant to produce new flowering stems from the crown. If stems don’t pull away easily, use pruning shears to cut them at the base.

In late fall, after flowering has finished, cut back the entire plant to approximately 2 inches above ground level. This encourages robust growth in the following season and helps prevent disease by removing aging foliage.

Winter Care

Winter protection requirements vary based on your climate zone:

• Zones 8-10: Minimal protection needed; apply a light mulch of leaves or straw to protect the crown
• Zones 6-7: Apply a thick layer (3-4 inches) of mulch after the ground freezes to insulate the root system
• Zones 5 and below: Consider growing in containers that can be relocated to a protected area (garage, basement, or cool greenhouse) during winter months

Dividing and Transplanting

Alstroemeria benefits from division every 3-4 years to maintain vigor and flowering performance. The best time to divide established clumps is in early spring just as new growth begins to emerge. Carefully lift the entire clump, divide it into sections ensuring each division has several growing points, and replant promptly.

Common Problems and Solutions

Pests

While generally resistant to serious pest problems, Alstroemeria can occasionally be affected by:

• Aphids: Control with insecticidal soap or a strong stream of water
• Slugs and snails: Apply organic slug bait or create barriers around plants
• Spider mites: Increase humidity and treat with insecticidal soap if infestation occurs

Diseases

The primary diseases affecting Alstroemeria include:

• Root rot: Caused by overwatering or poor drainage; prevent by improving soil conditions
• Powdery mildew: Appears in humid conditions with poor air circulation; treat with fungicide if severe
• Virus diseases: Can cause mottled foliage and reduced vigor; remove and destroy affected plants

Varieties to Consider

Modern breeding has produced an impressive range of Alstroemeria varieties suitable for different garden situations:

• Dwarf varieties (8-12 inches): ‘Princess’ series, ‘Little Miss’ series—perfect for containers and front-of-border plantings
• Medium varieties (1-2 feet): ‘Inca’ series, ‘Summer Breeze’—versatile for borders and cutting
• Tall varieties (2-4 feet): ‘Third Harmonic’, ‘Apollo’—excellent for back of borders and dedicated cutting gardens

Using Alstroemeria in the Garden

With their extended bloom period and variety of heights and colors, Alstroemeria can fulfill multiple roles in garden design:

• Plant in mixed perennial borders for reliable summer color
• Combine with roses for complementary flowering periods
• Create dedicated cutting gardens for abundant flower production
• Use dwarf varieties in rock gardens or as edging plants
• Grow in containers for patios, decks, and entryways

Cut Flower Production

Alstroemeria makes exceptional cut flowers, often lasting 2-3 weeks in arrangements. For best results:

• Harvest stems when flowers are just beginning to open
• Cut in the morning when stems are fully hydrated
• Place immediately in clean water
• Change vase water every 2-3 days to extend vase life
• Remove any foliage that would be below the water line

Frequently Asked Questions

Q: Are Alstroemeria plants toxic?

A: Yes, all parts of Alstroemeria plants contain toxins that can cause irritation if ingested. The sap can also cause skin irritation in sensitive individuals, so wearing gloves when handling these plants is recommended.

Q: Why isn’t my Alstroemeria flowering?

A: Insufficient flowering is typically caused by inadequate sunlight, improper fertilization (too much nitrogen), or overcrowding. Ensure your plants receive at least 6 hours of sun daily and are fed with a high-potassium fertilizer during the growing season.

Q: Can Alstroemeria be grown from seed?

A: While possible, growing Alstroemeria from seed is challenging and time-consuming. Seeds require stratification (cold treatment), and plants grown from seed may not come true to the parent plant. Most gardeners prefer to start with established plants or divisions.

Q: How do I overwinter Alstroemeria in cold climates?

A: In zones 5 and colder, grow Alstroemeria in containers that can be moved to a protected location for winter. Maintain temperatures between 35-45°F, water sparingly, and return outdoors after all danger of frost has passed in spring.

Q: Why are the leaves on my Alstroemeria turning yellow?

A: Yellowing leaves can indicate several issues, including overwatering, poor drainage, nutrient deficiencies, or natural senescence. Check soil moisture levels first, and ensure plants are not sitting in waterlogged conditions.

Author

Srija Burman

 

Srija holds an MA in English Literature from the University of Calcutta and a PG diploma in Editing and Publishing from Jadavpur University. Her interest in writing and editing ranges across niches, including academics, sports, and human psychology.

Read full bio of Srija Burman