How to grow alstroemeria and best varieties

Alstroemeria are beautiful perennials that are ideal for summer borders and as cut flowers in a vase. They’ve benefitted immensely from recent breeding work and the newer varieties are long-flowering, and come in a range of shades and patterns. Bred in the Netherlands, the Summer Paradise series, which all have ‘Summer’ in their name, standout in particular.

Which? Gardening magazine grew a range of popular varieties in the north and south of the UK over two years to see which would give us the best display and be hardy enough to get through UK winters.

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Key facts

PLANT TYPE Herbaceous perennial

POSITION Full sun or partial shade

SOIL Fertile and free-draining

How to grow alstroemeria: month by month

Best alstroemeria varieties

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Full testing results for alstroemeria

Alstroemeria for pots

USING THE TABLE OVERALL RATING Ignores price and is based on flowering duration 25%,flower impact 20%, flower coverage 20%, suitability for pots 20%, weather resistance 5%, pests & disease resistance 5%, appearance when going over 5%.

Alstroemeria for borders

USING THE TABLE The more stars the better. BB/RC = Best Buys/Recommended. OVERALL RATING Ignores price and is based on: flower duration 30%; flower impact 20%; display 20%; foliage 10%; need for support 10%; pest and disease resistance 10%.

How we test alstroemeria

 In spring, we purchased 17 varieties of alstroemerias. We planted three plants of each variety at our Capel Manor trial site in north London in mid-May, after all danger of frost had passed. A further three plants of each varietywere planted at our northern trial siteat Alnwick Garden, Northumberland. We assessed the plants throughout the summer. We looked at how well they filled out with blooms, the length of time they flowered for and how attractive each variety was. We also checked for any pests and diseases. The plants remained in the trial beds over winter. We assessed how well they survived the colder months and how well they flowered into a second season.

Caring for your plants

Planting

We found that bare-root plants don’t grow particularly well, so we would recommend buying potted plants wherever possible. Alstroemerias prefer full sun, but can tolerate partial shade. Plant in a sheltered, sunny border, or grow in pots using a Best Buy compost for containers with a Best Buy controlled-release feed.

Feeding and watering

Alstroemerias don’t need a lot of watering, but if you keep them well fed and watered they will flower for longer. Use a liquid tomato feed once a week if they have pale leaves or the display starts to weaken.

Deadheading

Once all the flowers on a stem have finished, remove the whole stem, pulling it from the base. Always pull blooms like this if you’re picking them for cut flowers.

Overwintering

Alstroemeria are hardier than you might think and, if their tuberous roots are planted deeply, they can survive quite hard frosts. However, they still appreciate a layer of mulch over the crown at the end of the season. 

If you’re growing them in pots, then they will overwinter quite happily in a frost-free greenhouse or outside in a sheltered spot with their pots wrapped in bubble plastic. Watch out for pests, such as whitefly, that will feed on the tender green leaves over winter. 

Although the green leaves may die back completely, it’s worth waiting until late spring to see if your plants have made it through the winter. Some pots that we left out over the winter were bursting with bloom again by late May.

Common growing problems

Slugs and snails

Watch out for slugs and snails in spring as they may nibble the young shoots. Use organic slug pellets or biological-control nematodes (slugs only).

Read more about slugs and snails

Greenfly

Greenfly might also invade the young plant, so squash these if you find any.

Read more about greenfly

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