Magnolia campbellii survey 2015

The Royal Horticultural Society in association with seven of the Great Gardens of Cornwall and The Nare Hotel have joined forces to chart the arrival of Spring in 2015. To help us do this, complete the survey to tell us when you first saw Magnolia campbellii (a spectacular pink and white flowering tree) flowering. The first results are in - this is the current map.

Magnolia campbellii  is a large, deciduous (loses its leaves in winter) tree. Blooms from early spring before the leaves appear.

Magnolia campbellii is a large, deciduous (loses its leaves in winter) tree. Blooms from early spring before the leaves appear.

Quick facts

Common name Magnolia campbellii
Latin name Magnolia campbellii
Group Tree
Flowering time Spring
Planting time Autumn
Height and spread 15m (50ft) and 10m (30ft)
Aspect Sun
Hardiness Hardy (but deeper-coloured forms are less hardy)
Difficulty to grow Moderate

How to take part

Complete the survey

Seen a Magnolia campbellii? Fill out the survey to tell us when you saw the first blooms of 2015.

Share your magnolia photos

Even if you don't see a Magnolia campbellii, upload your beautiful magnolia photographs to the RHS on Twitter: @The_RHS using #hellomagnolia

The results

  • The first results are in! See our map for up to April 10 2015, which shows that the trees in the northern England and the west-coast of Scotland are beginning to bloom, following those which came first in Cornwall. You can hover over the pink dots for details of each entry
  • For regular updates on the blooming of the trees in seven great Cornish gardens, see the Great Gardens of Cornwall Spring Story pages that feature their 'bloom-ometers'
  • Look out for the emerging results of the survey on the RHS website this spring and summer

What is Magnolia campbellii?

To take part in the survey, we need you to tell us when you first saw Magnolia campbellii coming into flower. But, how can you tell it apart from other magnolias? Here's our guide and gallery:

  • Magnolia campbellii is a large, deciduous (loses its leaves in winter) tree
  • Blooms from early spring before the leaves appear
  • Flowers are up to 30cm (1ft) across; goblet-shaped at first and then spread wide like waterlilies
  • There are up to 16 tepals (petals), which are usually pink within, deep-rose without. There is some variation in colour, however, in shades between white and deep rose-purple
  • For further images, see the RHS Rhododendron, Camellia and Magnolia Group page on M. campbellii

What's this survey for?

Seven magnificent Magnolia campbellii are being watched with interest to monitor the arrival of spring in the UK.

In recent years, the opening of magnolia blooms in Cornwall, which locally heralds the arrival of spring, has been as much as a month earlier than the Met Office ‘official date’ (this year, 1 March). To track the timings accurately, head gardeners at Caerhays Castle, The Lost Gardens of Heligan, Trebah, Tregothnan, Trengwainton, Trewidden and Trewithen (all part of the Great Gardens of Cornwall group) are working with The Nare Hotel, Veryan-in-Roseland, to document flowering dates.

Each head gardener will update the number of open blooms on the Great Gardens of Cornwall website.

When all seven trees have 50 open blooms, the project will announce the arrival of spring in Cornwall.

Toby Ashworth, Proprietor of The Nare Hotel, began the project two years ago. ‘We needed to show people that the best time to see magnolias in full bloom in Cornwall is February and March,’ he said.

Nationwide flowering

By incorporating the Cornish data, the RHS is expanding the project with a survey tracking the opening of M. campbellii blooms across the UK. Gardeners are asked to contribute to the online survey with data of where and when they see trees in bloom.

The results will be illustrated on the RHS website. Leigh Hunt, RHS Principal Horticultural Advisor, said, ‘This is a real toe in the water for us on how we capture phenological data. There will be value in repeating it so we can see seasonal differences.’

Check this page again later in summer for the results.


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