Muscari (in containers) trial results 2024

Objectives and purpose of the trial

The focus of this trial was on Muscari (grape hyacinth) cultivars as container plants. The last time Muscari was trialled at the RHS was in 2003, as part of the Hyacinthaceae trial. Since then, new selections have been introduced. The RHS Trials team wanted to compare new and established cultivars for the RHS Award of Garden Merit (AGM) and to see how they perform.
View of Muscari plants growing in containers in March 2024
Muscari planted in terracotta pots at RHS Wisley in April 2024

What is an RHS Award of Garden Merit?

The RHS Award of Garden Merit (AGM) is intended to help gardeners choose plants that are likely to perform well, and is only awarded to plants that are:

  • Excellent for ordinary use in appropriate conditions
  • Available
  • Good constitution
  • Essentially stable in form and colour
  • Reasonably resistant to pests and diseases

Judging criteria

The following factors were all taken into consideration as part of the judging of the trial:

  • Flower form, uniformity and impact
  • Length of flowering period

  • Weather resistance
  • Leaf quality and prominence

Muscari AGM winners

This bright spring Muscari display showcased the beautiful diversity of grape hyacinths and allowed the judges to grant 13 new AGMs and reconfirm two AGMs, updating the list of existing AGMs to reflect the current availability of the best Muscari to buy for containers.

For us judges, the form of the flower and length of flowering is important, as is the quality and dominance of the foliage. You don’t want leaves obstructing the blooms.

Camilla Bassett-Smith, RHS Trial judge

Why the AGM was awarded

New AGM winners with forum comments and hardiness ratings

Muscari ‘Alaska’ AGM (H6) 2024

  • Forum comment: Flowers a uniform soft blue colour, fading darker blue, almost waxy and very weather resistant. Flowerheads dense. Foliage heavy and flowers took a while to break through. If bulbs planted with more space the foliage would look better
  • Flowering time: Late season, mid March to late April

Muscari ‘Alida’ AGM (H6) 2024

  • Forum comment: Flowers big, in proportion with the foliage. Good bicolour flower colour. Held well, on tall, strong, straight stems. Good foliage quality. Lots of bulbs producing a second flush of flowers
  • Flowering time: Early season, early February to March

Muscari ‘Atlantic’ AGM (H6) 2024

  • Forum comment: Floriferous. Good, clean mid blue flowers. Consistently two flowers per bulb. Compact, foliage neat and in proportion, not overpowering
  • Flowering time: Mid to late season, late March to April

Muscari ‘Big Smile’ AGM (H6) 2024

  • Forum comment: Exceptional impact. A standout early season flowerer. Went over well. Wow from a distance.
  • Flowering time: Early season, early February to March

Muscari ‘Carola’ AGM (H6) 2024

  • Forum comment: Attractive conical flower shape, good bicolour. Consistently two flowers per bulb on straight stems, second flowers matching the height of the first flowers. Healthy, fresh foliage, in proportion. This is an armeniacum/aucheri hybrid with grey-tinged, boat ship-tipped leaves. Not untidy when going over. Brilliant in a container
  • Flowering time: Early season, early February to March

Muscari ‘Casablanca’ AGM (H6) 2024

  • Forum comment: Got better and better. Floriferous but not crowded. Flowers small, white with a pink blush as going over, held on straight stems that held up well and in proportion with the light green leaves. Foliage very neat, narrow-pointed and even. Stunning container plant
  • Flowering time: Mid to late season, late March to April

Muscari ‘Esther’ AGM (H6) 2024

  • Forum comment: Flowers icy blue early in the season, later with three tiers of colour; white sterile flowers, blue fertile flowers that turn darker blue as they go over. Flower stems upright. Foliage neat. Dainty and compact. Went over well. Consistently two flowers per bulb
  • Flowering time: Early to midseason, March

Muscari ‘Night Eyes’ AGM (H6) 2024

  • Forum comment: Elegant form. Distinctive, different look. Good impact, flowers dark with contrasting white teeth. Flower stems holding up, producing a second flush of flowers. Foliage upright, making it great for interplanting. Potentially a hybrid containing M. neglectum
  • Flowering time: Late season, March to April

Muscari ‘Peppermint’ AGM (H6) 2024

  • Forum comment: All round beauty. Uniform, with flowers held on straight, sturdy stems above the compact foliage. Flowers pale blue at first, ageing tri-coloured, with darker older flowers. Long flowering season, with a second flush of flowers. Ages really well
  • Flowering time: Mid to late season, March to April

Muscari ‘White Spear’ AGM (H6) 2024

  • Forum comment: Great flower form, pure white flowers held at a good height on straight, weather resistant stems. Fading with a pink blush as they go over. Large, well-structured, uniform plants with good green leaves. Some bulbs with three flower stems. Long flowering season
  • Flowering time: Mid to late season, March to April

Muscari armeniacum ‘Manon’ AGM (H6) 2024

  • Forum comment: Impressive. Dense, icy blue flowers, with good gradation of colour. Even height flower spikes. Foliage not intrusive. Larger than ‘Valerie Finnis’ with better foliage
  • Flowering time: Mid to late season, March to April

Muscari aucheri ‘Ocean Magic’ AGM (H6) 2024

  • Forum comment: Stunning. Neat, lovely shaped plants with beautiful tricoloured flowers
  • Flowering time: Mid to late season, March to April

Muscari latifolium ‘Grape Ice’ AGM (H6) 2024

  • Forum comment: Eye-catching from a distance. Very distinct, grape-coloured fertile flowers and sterile flowers that start blue and fade paler, finishing white. Holding well, some unevenness that would even out next year. Reliably flowering from small bulbs
  • Flowering time: Midseason, March to early April
Reconfirmed AGMs with forum comments and hardiness ratings

Muscari ‘Jenny Robinson’ (syn. ‘Baby’s Breath’) AGM (H5) 2004

  • Forum comment: Dainty. Distinctive, desirable icy pale blue flowers. Consistent, stood up over whole season. Foliage not overwhelming
  • Flowering time: Mid to late season, March to April

Muscari ‘Siberian Tiger’ AGM (H6) 2021

  • Forum comment: Performed well. Uniform, with large flowers. Distinctive greyish, almost tulip-like foliage. Filled the container although bulbs weren’t planted up to the edges
  • Flowering time: Mid to late season, March to April
Judging of the Muscari trial at RHS Wisley in March 2024
Forum judging the Muscari trial at RHS Wisley in April 2024

AGMs rescinded

For this Muscari trial, no existing RHS Award of Garden Merit (AGM) selectons lost their AGM. The trial judges considered that the five species of Muscari with AGMs, and two cultivars that were’t available to include in the trial should be reassessed separately by the RHS Alpine and Rock Garden Plant Committee.
Muscari to be reassessed

Muscari armeniuacum AGM (H6) 1993

  • Forum comment: Plants bought from Holland are always the same form, as included in the trial. This entry has performed well in a container, uniform with great flower density. Muscari armeniacum is variable in the wild and there could be variation in the plants supplied as M. armeniacum from other sources. When established the species can be fast spreading and it pushes up early leaves that create a messy display

Muscari azureum AGM (H6) 1993

  • Forum comment: Trial entry was a mixture of different species and selections which couldn’t be judged

Muscari latifolium AGM (H6) 2003

  • Forum comment: This species didn’t perform well as a container plant, the bulbs were small and arranged in the centre of the container. Might have performed better in a smaller pot. A good garden plant. The species is consistent in the wild

Muscari pseudomuscari AGM (H5) 1993

  • Forum comment: Not included in the trial – no longer grown in Holland. Flowers in February. Variable

Muscari aucheri AGM (H6) 1993

  • Forum comment: Not included in the trial – no longer grown in Holland

Muscari armeniacum ‘Christmas Pearl’ AGM (H6) 2003

  • Forum comment: Not included in the trial – more than one selection known in cultivation under this name. No longer grown in Holland

Muscari armeniacum ‘Saffier’ AGM (H6) 2003

  • Forum comment: Not included in the trial – Sterile, silvery blue late flowers. No longer grown in Holland

Plants and location

What was planted?

Fifty different Muscari selections were grown in pots, representing many of the Muscari that are currently available. This includes some species, some well-known selections, as well as some new introductions. Muscari comosum ‘Plumosum’ has been known since 1612. ‘Nature’s Beauty’, ‘Emmy’ and ‘Flower Desire’ were all registered in 2023. Many of the bulbs will form part of an alpine collection after the trial, or be planted out into the wider garden.

Where was it planted?

The bulbs were planted in terracotta containers (37cm diameter), 10cm deep in the Trials Garden at RHS Wisley, Surrey. Here are some considerations for planting out Muscari:

  • Muscari are hardy and can be planted in the ground, or containers, in a sunny or partially shaded, free-draining site
  • They are perennials and will come back year after year
  • Muscari are small spring-flowering bulbs, with vibrant blue, light blue, pink, white or even yellow flowers in some species

  • Muscari combine well with other spring flowers. Try planting under taller plants like daffodils or clump-forming perennials such as peonies with colourful spring foliage
  • Muscari are early sources of pollen and nectar for pollinators
  • Some grape hyacinths spread more vigorously than others

Muscari facts

Some Muscari selections naturalise well in garden borders and lawns, forming brilliant colourful carpets. If you want to reduce their spread, cut back flowers before seeds are fully developed.

Cultivation

Planting process

The Muscari bulbs arrived in October 2023, for planting out in the first week of November. The aim was to plant 100 bulbs of each entry in containers with a potting mix of peat-free compost and grit, and a top dressing of grit was also applied to each container. The bulbs were arranged concentrically from the centre outwards and with the bulbs touching each other.

Size differences between each entry meant that for some entries, 100 bulbs fitted easily within the container with a gap around the edge. Some bulbs just fitted into the container, and for others, 100 bulbs couldn’t fit. The number of bulbs planted for each trial entry was recorded.

The pots were left outside over winter to expose the bulbs to the winter weather. Where very low temperatures were forecast, the pots were covered with fleece, as the Trials Garden site is very open and prone to extremes.

How plant health was managed

Challenges

The Muscari were generally not affected by any diseases or pests.

On planting of the bulbs, it was noticed that some bulbs were covered in aphids. Each entry was dunked into a preventative soapy solution before being planted.

Botrytis, grey mould, was identified on some of the trial entries showing leaf yellowing and dieback and a fuzzy grey mould. The entries were taken out of the trial display to reduce the spread of the fungus.

Although they are not usually a favourite snack for deers or rodents, the pots were initially surrounded by a fence to protect from any potential animal damage.

Watering

Spring rainfall was higher than average, however some of the most foliage-heavy trial entries required more watering as the rain wasn’t able to reach the compost.

Discoveries

While carrying out the trial, a lot of time was spent observing the plants, and details were noticed that did not relate to the formal trial assessment. Here are some of the interesting findings from the trial:

2024

As a one-year container trial, planting of the bulbs had been carried out later to delay the emergence of the foliage. This is good advice to give gardeners planning a container display. The forum predicted that in the second year, these containers would become a mass of foliage, especially entries producing lots of bulbil (young plant) offsets, the bulbs will be packed too tightly. To continue with a container display the forum would recommend feeding, unpotting and repotting the bulbs to the original spacing.

Did you know?

On sunny, warmer days most Muscari flowers are sweetly scented. Muscari macrocarpum ‘Golden Fragrance’ is a really different selection with yellow flowers and a much stronger fragrance. Muscari racemosum has a more musky scent.

Who was involved?

Judges of the trial

The Muscari trial judges met four times in March and April 2024, to assess the plants from the first to the last flowers. The trial judges included 10 experts, involving collection holders, horticulturalists, garden writers, members of the RHS Bulb Committee and RHS Alpine and Rock Garden Committee.

The Muscari judges included: Alex Hankey (Alpine Team Leader, RHS Wisley), Andy Byfield (Botanist and Conservationist), Camilla Bassett-Smith (Television Presenter and Writer), Coralie Thomas (Assistant Head Gardener at Great Dixter House and Gardens), John Amand (Owner, Jacques Amand International), Kit Strange (Bulb specialist, RHS Alpine and Rock Garden Committee), Matt Bishop (Bulb specialist, RHS Bulb Committee), Ray Drew (Alpine Garden Society and RHS Alpine and Rock Garden Committee), Richard Hobbs (Botanist, Muscari National Collection Holder) and Teresa Clements (RHS Bulb Committee Chair).

Suppliers to the trial

List of plants in the trial

View all the cultivars of Muscari trialled at RHS Wisley
  • Muscari ‘Alaska’
  • Muscari ‘Alida’
  • Muscari ‘Aqua Magic’
  • Muscari ‘Atlantic’
  • Muscari ‘Big Smile’
  • Muscari ‘Bling Bling’
  • Muscari ‘Carola’
  • Muscari ‘Casablanca’
  • Muscari ‘Cool Blues’
  • Muscari ‘Emmy’
  • Muscari ‘Esther’
  • Muscari ‘Flower Desire’
  • Muscari ‘Flower Power’
  • Muscari ‘Ivor’s Pink’
  • Muscari ‘Jenny Robinson’ (syn.‘Baby’s Breath’)
  • Muscari ‘Joyce Spirit’
  • Muscari ‘Julia’
  • Muscari ‘Lindsay’
  • Muscari ‘Marleen’
  • Muscari ‘Mount Hood’
  • Muscari ‘Mountain Lady’
  • Muscari ‘Nature’s Beauty’
  • Muscari ‘Night Eyes’
  • Muscari ‘Peppermint’
  • Muscari ‘Pink Sunrise’
  • Muscari ‘Siberian Tiger’
  • Muscari ‘Soulmate’
  • Muscari ‘Superstar’
  • Muscari ‘Venus’
  • Muscari ‘White Spear’
  • Muscari armeniacum
  • Muscari armeniacum ‘Blue Spike’
  • Muscari armeniacum ‘Cupido’
  • Muscari armeniacum ‘Dark Eyes’
  • Muscari armeniacum ‘Fantasy Creation’
  • Muscari armeniacum ‘Manon’
  • Muscari armeniacum ‘Touch of Snow’
  • Muscari armeniacum ‘Valerie Finnis’
  • Muscari armeniacum ‘Snowqueen’ (syn. of ‘Venus’)
  • Muscari aucheri ‘Blue Magic’
  • Muscari aucheri ‘Ocean Magic’
  • Muscari aucheri ‘White Magic’
  • Muscari azureum
  • Muscari botryoides ‘Album’ misapplied (association with M. botryoides queried)
  • Muscari comosum
  • Muscari comosum ‘Plumosum’
  • Muscari latifolium
  • Muscari latifolium ‘Grape Ice’
  • Muscari neglectum
  • Muscari racemosum
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