The Alstroemeria, or Peruvian lily, is a long-lived, free-flowering perennial that originates from South America. They grow from tubers, and produce lots of colourful flowers from June through to the first winter frosts on stems up to 1.2m tall, depending on the variety. The flowers come in a wide variety of colours, including shades of red, orange, purple, green and white, generally patterned with darker freckles, stripes and streaks. They have six ‘tepals’ – the petals and sepals are indistinguishable, six prominent, curving stamens and a three-lobed stigma.
There are approximately fifty species of wild Alstroemeria. Despite the common name, the centres of distribution are two distinct areas in central Chile and eastern Brazil, and not Peru. Many hybrids and around 200 cultivars have been developed, with enthusiasts breeding for flower colour and markings. The range of natural colours has been successfully expanded to a kaleidoscopic choice of reds, purples, pinks, greens, yellows, oranges, apricots and white.
The most popular garden hybrids come from crosses between species from Chile that are winter-growing and species from Brazil that are summer-growing. This has produced evergreen plants that will flower from early summer late into the autumn. They will continue to flower into early winter in an unheated greenhouse.
While not a true lily, there is some resemblance in the flower. Alstroemeria has become a stalwart of the commercial cut flower trade, as the flowers are colourful and reliable, and last for several weeks in a vase.
This article describes the varieties of Alstroemeria that are available, and provides tips on caring for the plants and how to ensure a good supply of beautiful cut flowers for the home.
With around 200 varieties of Alstroemeria available from specialist nurseries and garden centres, the gardener can feel a little spoiled for choice. Some growers sell mixed tuber packs that are good value for money, but which may be unpredictable in terms of colour and final plant quality. These collections typically include ‘Inca’, ‘Little Miss’ and ‘Princess’ selections.
This selection will include a range of pastel-coloured Alstroemeria with some more vivid, larger-flowered types. They are likely to include the pink, white and yellow ‘Inca Smile’. The average height is 45cm to 50cm.
The Little Miss Series
These are dwarf varieties growing up to 20cm tall. The flower colours are mixed, and will include many shades of pink. They typically flower from July until early September.
The Princess Series
These are vigorous hybrids and varieties that have been developed for the cut flower trade, and they will provide colour from June until November. The sizes are mixed, though most tend to be short and robust in stature.
There have been many horticultural trials to determine the best cultivars for garden use, and those with the RHS Award of Garden Merit are always a reliable choice. These include the following favourites:
White and yellow; ‘Apollo’
Reds and yellows; ‘Phoenix’, ‘Red Elf’, ‘Sonata’, ‘Tessa’, ‘Yellow Friendship’
This is one of the most traditional and popular tall varieties, growing to around a metre tall and producing masses of bright white flowers with yellow throats. It has a stout stem and it can produce great cut flowers from June through to November.
Alstroemeria ‘Orange Glory’
Another tall cultivar, growing nearly a metre tall, ‘Orange Glory’ has rich orange flowers with a yellow speckling in the throat. It has strong stems and it makes an ideal cutting variety.
‘Friendship’ also grows to nearly a metre in height, and it has pale yellow flowers with rich pink patterning. It is another good variety for the vase and a favourite for bouquets.
Alstroemeria ‘Indian Summer’
‘Indian Summer’ is also popular, and is slightly more compact at around 70cm tall. It has warm orange and yellow flowers with complex petal patterning, and complementary bronze foliage.
Another mid-sized variety at approximately 75cm tall, ‘Phoenix’ has bright magenta flowers from June through to November. It has additional interest in its unusual variegated green and white leaves.
Alstroemeria inticancha ‘Dark Purple’
This is a dwarf cultivar with rich, dark purple flowers that are borne of stems just 20cm in height. It is ideal for growing in containers, patio planters and window boxes.
Alstroemeria are generally available from garden centres and nurseries as container grown plants and bare root tubers. The former are much more reliable and some gardeners have problems raising good plants from loose or packaged tubers. Young, named variety plants in 9cm pots are best, as these should have been raised from high quality stock by micro-propagation. They will not only transport well and grow on quickly once planted out in the garden, but they will also produce flowers that look like the ones on the label.
Trays or modules of Ligtu hybrid Alstroemeria seedlings are also sold in some outlets, but these will have been raised from seed and are of less reliable quality and could produce a mix with some inferior plants with muddy flower colours.
Alstroemeria should be planted out once the risk of frost is over, usually mid to late May, depending on geography and exposure. They can be planted out earlier at risk of losing the new growth or even the plant, or early season purchases can be grown on in a greenhouse, cold frame, conservatory or a sunny windowsill until the danger of frost has passed.
While container grown plants can be planted out at any time in the summer, this is not recommended after early September, as they need time to establish before winters first frosts.
Alstroemeria are not particularly fussy about garden conditions, through the ideal location is a spot sheltered from the wind and in full sun or light shade for part of the day. They will not do well in heavy soils and will not survive waterlogged conditions.
Modern Alstroemeria varieties require minimal maintenance and will grow over subsequent summers into robust clumps. Plant tall varieties at the back of the border at 60cm spacing, and dwarf varieties in more forward positions 40cm apart. They develop an even greater impact when they are planted in groups of similar colours.
Before planting, stand the pot in a shallow tray of water for thirty minutes or so to thoroughly wet the roots and tuber. Meanwhile, prepare the border by digging and breaking up the soil down to a depth of 25cm, add some garden compost or other suitable organic matter to the base of the hole and the excavated soil, together with an organic fertiliser at around 100g per square metre. Add some horticultural grit to slightly heavy soils to improve the drainage. Adjust the hole so that the compost surface around the plant sits at the same level as the surrounding soil and back-fill the hole.
Firm in carefully but firmly to eliminate any air pockets and encourage rapid root expansion into the surrounding soil, and water well. The freshly planted Alstroemeria will need frequent watering until well established. Mulching to a depth of at least 5cm with garden compost is recommended to retain moisture and to keep the rhizome cool in summer. Tubers exposed to hot, dry conditions will not flower as well as those kept moist and cool through the summer.
Once growing well, taller varieties may need supporting with pea sticks, canes and twine, or herbaceous border frames.
The plants will be particularly vulnerable to frost damage during their first two winters in the garden. To protect them, cut back the old growth in October or early November and mulch the whole area around them with bark, compost, bracken or straw to a depth of 20cm. This should be removed and composted once frosts have passed the following spring. By their third winter, the plants should have developed deep enough roots to look after themselves through the winter, though an annual application of a 5cm layer of compost mulch will continue to improve moisture retention, drainage and root protection.
Pot-grown plants should be brought into an unheated greenhouse or cold frame, at least for their first two winters. Alternatively, the whole pot can be planted into a border for the winter, to be protected by mulching in the same way as the garden-grown plants.
Ideally, Alstroemeria should be located in full sun, although they will tolerate partial shade. Specialist growers often suggest that a position that provides the plant with at least six hours of morning sunlight brings the best flowering performance.
Established plants are drought tolerant, but they should be watered in dry periods, especially in their first two summers. Frequent watering will encourage free flowering, but never waterlog the soil or compost.
Container-grown plants require frequent watering to maintain moisture to the roots and to help cool the tuber in pots kept in direct sunlight.
Alstroemeria will thrive in most soil types so long as it has good drainage. The ideal is an organic-rich, free-draining loam that is either neutral or slightly acidic. Very heavy clay soils are not suitable, though moderately heavy soils can be improved with compost, well-rotted manure or gravel. Very sandy, free draining should be improved with organic matter to improve its moisture-retention, and the plants watered more frequently, especially in the summer after planting.
Provide a high potash fertiliser such as a liquid tomato feed weekly during the flowering season.
Alstroemeria can be grown in containers, and the dwarf varieties such as Alstroemeria inticancha ‘Dark Purple’ are ideal. Pots should be at least 40cm in diameter, filled with a good quality peat-based or John Innes No 2 compost with a good handful of horticultural grit. They will need frequent watering, and feeding once per week with a high-potash liquid feed once the first flower buds form. The pots can be kept outside through the summer once established, or plants can be raised and kept permanently in an unheated greenhouse to extend the flowering and cutting season. The containers will need to be kept in a frost-free place to protect the tubers during the winter.
The taller varieties can be raised in pots, but they will grow taller if raised under glass, and containers will need to be selected carefully. The tallest may grow up to 1.5m and risk becoming top heavy. At this height they will need to be staked or grown against nets.
Water pots in the greenhouse well throughout the summer to keep the plants blooming, provide shading from the hottest sun, and ensure good ventilation. Thin the stems of a vigorous pot plant once a month by pulling out weaker stems and any that reach a metre tall without forming flower buds.
The plants can be re-potted every second year into a larger pot if necessary, but the roots do not enjoy disturbance so this needs to be done carefully and with minimum disturbance to the tuber and root-ball.
Looks good with
The brightness and extravagant hues of Alstroemeria flowers are not exactly understated, but they are probably unrivalled for adding a splash of unbridled colour and presence to a garden flower border. A mixed planting of Alstroemerias requires little additional colour, so they are best displayed against a shrubby backdrop or as part of a mixed herbaceous border with some more subtle perennials such as hardy geraniums, Achillea, Lysimachia and the paler varieties of delphinium and lupin. They also work well if backed by taller architectural grasses such as Stipa gigantea or the soft grey foliage of Artemisia stelleriana or Centaurea cineraria.
While not perhaps a traditional English cottage garden plant, carefully selected Alstroemeria can frequently be seen in more contemporary cottage garden style planting, with colours to complement English lavender, valerian, roses and hydrangea.
As one of the best cut flowers, Alstroemeria can also be grown in cutting gardens, either in purpose-made borders or raised beds in the allotment alongside vegetable beds. Rows of Alstroemeria can be raised with other cutting flowers such as Cosmos, Achillea and Echinacea.
Alstroemeria does not require pruning, but spent flowers should be deadheaded by removing the whole flower stem from ground level. These stems should be cut off in the first flowering season, but in subsequent years they can be pulled out from the base as the flowers fade, as they will respond to the damage by sending up more flower stems. For the same reason, flowers taken for the vase should be pulled from the base rather than being cut off.
Commercial growers propagate Alstroemeria by micro-propagation and tissue culture, but amateur gardeners are restricted to a choice of making new plants by means of seed or division.
In order to raise new plants that are true to the parents, named cultivars should be propagated by division in April. While they do not enjoy root disturbance, vigorous clumps can be divided every two years to help expand numbers of plants.
The tuber and roots are fragile and they need to be lifted with caution. They should be replanted as soon as possible after careful division by pulling the roots apart gently by hand.
Alstroemeria ‘Ligtu hybrids’ can be propagated from seed bought from seed merchants or hand-collected from plants in the garden. The seed pods should be gathered as they turn brown and kept in a closed paper bag until they open naturally. The seed should then be sown immediately as it does not keep well.
Collected or bought seed is best sown in the autumn in peat-free seed compost in 8cm pots. The seeds should be scattered onto the surface of the compost and then covered with a shallow layer of vermiculite. Put the pots into a propagator or cover them with a plastic bag to maintain humidity. Place in a warm place at around 20ºC for three weeks to promote germination, though it can be erratic, especially if the seed was not fresh.
The maturing seedlings can be planted out the following spring, though the roots are easily damaged so plant the whole pot as a clump with minimal root disturbance rather then trying to separate them out. The seedlings are unlikely to achieve flowering for the first two to three years of their life.
Common Alstroemeria Problems
Alstroemeria is not particularly prone to disease or pest problems, but inferior plants can suffer from a range of rots and viruses, and all are vulnerable to the garden’s ubiquitous slugs and snails.
Alstroemeria is rarely seriously troubled by aphids or other sap-sucking insects, and in a healthy garden natural predation will generally be sufficient to keep them under control. Thrips occasionally cause minor damage over a short period in the autumn. The young shoots are attractive to the ubiquitous slugs and snails, and may need some protection if the problem is particularly severe.
The plants can suffer from root, stem and crown rots caused by various fungi such as Fusarium, Phytophthora, Pythium and Rhizoctonia species, and viruses may occasionally be a problem. Badly affected plants should be destroyed and replaced with more resistant varieties. In general, the modern named cultivars are more resistant than the mixed Ligtu hybrids.
Q How can I make the most of Alstroemeria as cut flowers?
Alstroemeria makes an excellent cutting plant, as its colourful flowers are amongst the longest lasting cut blooms in the vase. For the same reason it is a firm favourite with florists for bouquets and arrangements.
Dedicated cutting flower beds or rows in an allotment facilitate a more productive, planned production system and help to avoid depleting the general garden borders of their colour.
The taller varieties such as ‘Apollo’ and ‘Orange Glory’ give more stature to an arrangement, and colours can be carefully selected for compatibility, or caution can be thrown to the wind by deliberately mixing together a huge variety of theoretically clashing colours for a striking display.
With careful attention, Alstroemeria flowers should last two to three weeks in a vase. Choose flowers that are just starting to open, and the cut stems should be transported in a plastic bag or preferably plunged in water immediately after cutting. Once in the vase, any wilting or damaged stems or sickly-looking flowers should be removed as soon as they are seen. Some professional florists suggest adding a drop of bleach to the water in the vase, and to replace it every four days.