Alpine and Rock Garden team blog
The Alpine and Rock Garden team looks after a fantastic range of plants from the world’s mountain ranges. This blog includes stories about individual plants, growing techniques and trips to see alpine plants in the wild. You can visit plants from Kew's collection of alpines in the Davies Alpine House, the Rock Garden and Woodland Garden and read this blog to find out how the team gets to grips with cultivating them.
In the Woodland Garden at Kew, the colourful carpet of fallen leaves is punctuated by tall burnished stems topped with golden seedheads. These are a reminder of the glorious June display of the giant Himayalan lily (Cardiocrinum giganteum).
Cardiocrinum giganteum seedheads in the Woodland Garden
This mighty plant comes from the Himalaya, growing in woodland clearings at altitudes of between 1,500 and 3,600 metres. The plants grow up to four metres tall and carry as many as 20 large, white, sweetly fragrant flowers on the single stem that emerges from each bulb.
The dramatic floral display of Cardiocrinum giganteum
The bulb takes about seven years to reach flowering size from seed, by which time it has a diameter of at least 20 centimetres and has pushed itself half way out of the soil. This levitation means that it is quite shallowly rooted, and it is not uncommon to find a flowering stem that has keeled over due to the weight of its waxy flowers.
l: The shallow roots and, top left, a glimpse of one of the offsets, produced around the base of the flowering stem
m: The offsets can be gently separated from the stem and replanted
r: Woodland Garden Volunteer, Kate, plants one of the offsets
Cardiocrinum giganteum is monocarpic, dying after flowering. However, it produces a number of new offsets which can be separated and replanted just below the soil surface. These take three to five years to flower, but never reach the stature of plants grown from seed.
The seedheads have three chambers, tightly stacked with flat triangular seeds each surrounded by a papery wing. We sow seed every year, to try to ensure a steady succession of flowering-size bulbs – the seed requires double stratification, which means it germinates after two winters in our outdoor seedframe. Seedlings are pricked out, four to a 5 cm pot and left to bulk up before being potted on as small bulbs and planted out when their bulbs reach around 2.5 cm in diameter.
The papery seeds are packed tightly into the large seedpods
The plant prefers a rich, moist, well-drained soil and is adapted to cool, damp Himalayan summers, so in the UK it is best grown in the dappled shade of a woodland garden. We also grow a variety from Yunnan, Cardiocrinum giganteum var yunnanse, which tends to have redder and shorter stems, and a brighter red in its blooms.
Cardiocrinum giganteum var. yunnanense
These dramatic structures are robust and longlasting: one of Kew's diploma students used the previous year's seed heads as decorative stakes on his vegetable plot - and an enterprising spider was quick to spot a hunting opportunity too!
Cardiocrinum seed pod with spider's web
- Katie -
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Scilla madeirensis is a fantastic species from, as you may have guessed from its name, the Atlantic island of Madeira. It is related to the tiny blue-flowered squills often seen in gardens but this plant is much bigger and flowers in the middle of winter. The violet-blue flowers are held in dense racemes that emerge from between bright green, pointed leaves.
The flowers of Scilla madeirensis
Only a few weeks ago the huge, purple bulbs of this plant were dormant. The leaves of this species last throughout the winter but by the summer they have died back and the plant is dormant during the long, dry summers in its natural home, where it lives on vertical rock faces. Early in October the bulbs are given fresh soil but unlike most bulbs, the roots do not die back completely so the hefty rootball has to be carefully cleaned up before new soil can be filtered in around the edges of its new pot.
Repotting the bulbs of Scilla madeirensis in early October
Kew first received this plant in 1976 when it was just one large bulb. Over the years it has multiplied but the bulbs are still attached to a thick basal plate just below the soil surface. The only way to split them is by cutting through this base. We now have several large pots of this plant in the Alpine Nursery. The bulbs are kept above the soil level to reduce the risk of them rotting.
Bulbs of Scilla madeirensis ready for their first watering
Once they have received some water, growth is remarkably quick. Only four days later the leaves had begun to shoot from the tops of the bulbs.
New growth just a few days after repotting
By the middle of November the flower spikes have developed and the first blooms are opening. It is then that the pots are moved into the Davies Alpine House and put on display. This is not a hardy plant and the pots are kept in a frost-free glasshouse in the nursery. It may be far from a true alpine but it does well in the Alpine House and at a time of year when any flowers are welcome, it makes an impressive sight.
Scilla madeirensis on display in the Davies Alpine House
- Richard -
4 comments on 'Flowering now: The giant Madeiran squill'
While on a visit to Munich this autumn I had an opportunity to join Jenny on a visit to the alpine garden run by Munich Botanic Garden, located high in the Bavarian Alps. This was a follow up to a trip I made to the Alpengarten in the summer of 2008 and gave me the chance to compare the flora at different times of year.
We drove south from Munich under low cloud but as we climbed the steep, winding track up the mountains, we rose above the gloom into the glorious weather on Mt Schachen.
The view from Mt Schachen
We caught some wonderful glimpses of the Koenigshaus, just above the alpine garden, which lies 2,000 metres above sea level, in the Bavarian Alps.
Koenigshaus in the Bavarian Alps
Jenny was here to collect seed from plants growing in the alpine garden so that she can offer them to other botanic gardens through Munich's annual index seminum (seed list). The altitude and aspect of the garden means that Jenny and her colleagues have great success with many plants that we at Kew find difficult in our relatively hot, dry corner of south-east England. However, several species I have grown from Schachen seed are now thriving in the Davies Alpine House, especially in the tufa mounds - a crumbly, open-textured rock that is ideal for growing a range of small alpine plants, such as those we saw on this mountain.
Jenny Wainwright Klein collecting seeds in the Alpengarten
This was probably Jenny's last visit to the garden before it is engulfed by the first heavy snow of winter, which was forecast to arrive in a couple of days. She collected, amongst others, seed from Himalayan Primula and Meconopsis species, and we both spent time trying to photograph Cremanthodium ellisii, which was flowering its socks off!
I worked at the Schachen garden in July 2008, just a few weeks after the snow had melted and when spring had truly sprung. It is fascinating now to see how the vegetation develops over the short, intense growing season high on the mountain, how the unbelievably rich spring flower meadows were now grazed and straw-coloured, and how the tall herbs had changed the shape and character of the garden as they shot skywards. Seeing the cultivation of these plants by our Munich colleagues gives us extremely useful pointers to their treatment at Kew. And, of course, stepping out of the garden onto the mountainside, I can see the Bavarian flora in its native habitat, and again, this informs the way I will try to grow all these fantastic plants in the Davies Alpine House at Kew.
- Katie -
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So, as Richard said in his introduction, the Alpine Nursery is tucked away behind the scenes at the north end of the Gardens at Kew. It’s located in an area called the Melon Yard where, surprise surprise, they used to grow melons. Now it’s rather different and houses three separate nursery areas; one supporting the work of the Jodrell Laboratory, another growing all the bedding and decorative plants that brighten areas such as the Palm House Parterre, the Duke's Garden and the Queen's Garden and then our nursery.
A view of the Alpine Nursery
The Alpine Nursery has three different types of structure. There’s a large glasshouse split into five separate zones which is heated just enough to keep the frost away in the depths of winter. Next, there’s a group of polythene tunnels covering plunge beds filled with sand and finally a couple of structures which are a little unusual. Imagine two large glasshouses with the sides and ends removed to leave just the roofs, underneath which are raised beds and mobile benches.
Plants protected from winter rain
We also have a separate area, the Alpine Yard, hidden behind the School of Horticulture with traditional brick frames and old-fashioned glasshouses (no computer-control here). Here we grow some shade-loving plants, but the real star of the show is the bonsai collection. This is diligently tended by our specialist, Richard Kernick, who looks after many attractive and aged trees which are displayed in rotation in the Bonsai House.
Hidden behind the School of Horticulture is the Alpine Yard
Back in the Melon Yard, Jeremy Broome oversees the bulbous collections and has special responsibility for a very nice group of Mediterranean plants. Sue Skinner looks after a variety of bulbs and alpines including large groups of campanulas, saxifragas, roscoeas and sempervivums. Kit Strange mainly tends bulbous plants along with some moist shade lovers. She has a large collection of alpines at home and also gives lectures to local Alpine Garden Society (AGS) groups and organises an AGS show every year north of London. Alina Syed is responsible for propagating material for the Rock Garden and likes to experiment with different techniques. And then there's me, Graham Walters. I oversee the whole nursery and have a special responsibility for growing cushion plants such as dionysias and androsaces.
Alpine nursery staff.
Back row: Graham Walters, Richard Wilford, Jeremy Broome
Middle row: Kit Strange, Alina Syed, Sue Skinner
Front row: Richard Kernick
Next time I’ll tell you more about the different parts of the nursery and our day to day activities. See you then.
- Graham -
1 comment on 'Introducing Kew's Alpine Nursery and the people who care for the plants'
You can just about have a cyclamen flowering in every month of the year but autumn is the time to see the widest range in one go. The most commonly grown and one of the hardiest species is Cyclamen hederifolium. It can begin flowering as early as July, but September and October are its peak months. The flowers appear before the leaves and they are shades of pale to rich pink or occasionally white. The leaves soon follow and are attractively marked with silvery patterns. These leaves last all winter and into spring before the plant dies down for its summer rest, an adaptation to the hot dry summer of southern Europe where it grows wild. You can find this species in Kew's Woodland Garden, Rock Garden and Davies Alpine House.
Cyclamen hederifolium in the Woodland Garden
Slightly less hardy but still worth trying in a sheltered spot outside is Cyclamen graecum. This has been grown outside on Kew's Rock Garden for several years but is also displayed in the Davies Alpine House. Like C. hederifolium, it has wonderful foliage with an array of markings making each plant unique. This species comes from southern Greece, the Greek islands, southern Turkey and northern Cyprus. The pink flowers are held on shorter stems than those of C. hederifolium and are often held just above the new leaves.
Cyclamen graecum in the Davies Alpine House
One more for a sheltered spot is the Turkish Cyclamen mirabile. Although shorter and more delicate looking then C. graecum, this has also survived outside on Kew's Rock Garden but often does best given a bit of protection in a cold frame or alpine house. Here, the flowers are protected from the weather and the tubers are sure of a dry summer. The leaves are rounded and when young, they often have a purplish flush on the upper surface. It is worth looking out for this plant in the Davies Alpine House.
Two other autumn flowering cyclamen that are best grown under cover are the North African species Cyclamen africanum and C. rohlfsianum. Cyclamen africanum has survived outside at Kew but is safest given a dry summer and a not too cold winter in a glasshouse. It is similar to C. hederifolium but has longer flower stems and wider, glossy leaves. Cyclamen rohfsianum, from northern Libya has fantastic leaves that can reach well over 10 cm across and have toothed margins. The flowers appear first and are held close to the ground. Grown in pots in the Alpine Nursery at Kew, this species can now be seen on display in the Davies Alpine House.
These are just a few of the 20 species of Cyclamen. Others to see now include Cyclamen cyprium, from Cyprus, the tiny C. intaminatum from Turkey and, also from Turkey, C. cilicium. In the winter look out for the toughest of the lot, C. coum, and then the spring species take over, including the parent of all those florist cultivars, C. persicum. The one that keeps the flowers going through the summer is the Central European C. purpurascens. So if you can't make it to Kew Gardens now there are plenty of other opportunities to see these amazing plants for yourself.
- Richard -
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Several people contribute to the Alpine and Rock Garden Team blog. Richard Wilford is the Collections Manager in the Hardy Display Section at Kew. His responsibilities include all the areas where alpines are grown at Kew Gardens. The three team leaders, Joanne Everson, Graham Walters and Katie Price, each have their own particular parts of the Gardens to look after. Between them, these four experts have over 55 years experience of growing alpines.
Alpines at Kew Gardens are not only grown to create colourful and informative displays, they also play an important role in the research Kew carries out around plant naming, classification, biodiversity and conservation.
Mountains are found on every continent and each range has its own unique alpine flora, but these plants are under threat from climate change. As temperatures rise, alpines are forced higher and will eventually have nowhere to go. The alpine collections at Kew are studied to help us all understand the mountain flora better and make informed decisions about protecting its future.
"Probably the most beautiful glasshouse in the world is the Davies Alpine House at the Royal Botanic Gardens Kew", John Hoyland, Gardens Illustrated, April 2011
Richard Wilford has written a book on alpines, 'Alpines from Mountain to Garden', published by Kew Publishing. You can buy it in the Kew shops or from Kewbooks.com.
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