First thoughts on trialling Shasta daisies

Leucanthemum- 'Real Galaxy'. Image © GardenPhotos.com

Shasta daisies have come a long way in recent years, with developments on both sides of the Atlantic, and this year I’ve been looking at some of the recent introductions in my new trial garden.

The great American plant breeder Luther Burbank is said to have created the Shasta daisy using some creative, though now discredited, hybridisations between leucanthemums and related genera. He made pollinations between various species and genera but it seems certain that the resulting seedlings were not actually hybrids: pollination but no fertilisation.

The first double-flowered variety was spotted from a train passing through Norfolk in eastern England, growing wild, by Horace Read. On his return journey he’s said to have pulled the emergency cord, jumped out, dug up the plant and quickly got back on the train. That was in the 1920s.

These days, one of the leading breeders is North American, Terra Nova Nurseries, the other British, RealFlor, with other breeders in North America, Britain and Holland also making improvements.

This year I grew almost all the recent Shasta daisy introductions. I can’t make definitive judgements in their first season, the plants went in at different times and varied in size enormously, but a few things are clear.

The range of flower forms is impressive with neat doubles and tightly anemone-centred forms and, while we still have no pink-flowered forms, the yellow-flowered varieties are becoming increasingly impressive.

As I write in early October, most still feature a few flowers except for 'Shapcott Gossamer' and 'Shapcott Ruffles' which have been over for many weeks, in spite of regular deadheading.

Both ‘Real Galaxy’ (above, in summer) and ‘Goldfinch’ are still opening new buds, as is ‘Victoria’s Secret’ but its stems are so thin that they’re collapsing under the weight of the flowers. ‘Lacrosse’ had a break but this morning I see that it's producing new buds. ‘Real Charmer’ has no buds coming but the open flowers still look good.

Next season will be a much better test as all will be starting from established plants. I’m looking forward to it, and all thanks to Luther Burbank and Horace Read.


Ivy: Friend or Foe?

Hederacolchica'Dentata Variegata'-26704

Ivy is a plant that divides opinions. Attractive foliage, good for wildlife, cools buildings… Invasive, ruins walls, harbours pests…. Research and opinion on all these issues has been in the news increasingly in recent years and now the most comprehensive book on ivies ever produced has been published by The Royal Horticultural Society.

Hedera: The Complete Guide by Hugh McAllister and Rosalyn Marshall is exactly that – the complete guide. With more than four hundred pages, and impressively illustrated in colour throughout, this is the second in the RHS Horticultural Monograph series which began with last year’s excellent book on kniphofias.

This is an attractively designed book – far more appealing than most gardeners expect from a serious plant monograph even though the predominant colour of ivies is, well, green. All the species are described in detail, but not in torrents of baffling technical language; two hundred cultivars are illustrated and described, and the fat descriptive checklist covers all the other names that have ever been used, over two thousand of them.

One very useful feature of the book is its use of the Pierot system of classification. This was created by Suzanne Pierot, the first President of the American Ivy Society, in the 1970s and divides ivies into nine convenient groups based on easily-seen features of the foliage. Brits are largely unfamiliar with this approach so its use in this book should help it stick.

HederaBookCover9781907057731But what does the book have to say about those pros and cons?
Attractive foliage? Obviously.
Good for wildlife? Yes. “Ivy berries are eaten by at least 17 species of bird in Britain indicating the importance of this plant group for the support of vertebrate wildlife…. They have a high energy, though low protein, content and form a large part of the diet of several species at this time of year (winter).” “The autumn flowering of ivy provides nectar for a wide range of invertebrates at a lean time of year.” Not to mention ivy as a valuable nest site.
Cools buildings in summer, warms buildings in winter? Yes. “Measurements on ivy-covered stone walls across several historic sites in England… showed that an ivy covering resulted in cooler walls in summer and warmer walls in winter.” “Recent research on the climate of southeast UK… suggests that a 21-37% reduction in winter heating could be achieved.”

Invasive? Sometimes. While most ivies can develop vigorous growth in their native habitats, it is almost always H. hibernica that causes problems as a non-native plant. “All ivies need not be banned in climates where invasive ivies are a problem. There are enough dwarf, miniature and slow-growing cultivars of H. helix to provide a good range of safe and attractive plants for indoor and outdoor use.” In my Pennsylvania garden, as soon as an ivy shoot penetrates the deer fence the deer eat it.

Damages walls? Sometimes. “Any increase in relative humidity due to wall plant cover is offset by lack of rain reaching the building.” But: “ivy can root into weakened historic walls or buildings, and can lift blocks of stone off walls” and also damage walls built and pointed using soft mortar.

Harbours pests? Sometimes. Ivy is attacked by viburnum scale which also attacks Viburnum tinus. “In pots, by far the most serious pest of ivy is vine weevil” – which attacks a wider range of other plants. I’d be interested to know if outdoor ivy has a role as a reservoir of vine weevil infestation.

This is an impressive book by one of our most seasoned horticultural taxonomists and a relatively young recruit to the RHS botany team. The RHS has more in the series on the way, I look forward to the series building into an invaluable resource.

Hedera: The Complete Guide by Hugh McAllister and Rosalyn Marshall is published by the Royal Horticultural Society at £40.00/$53.45.

You can read more about ivies in gardens and in the wild in these Transatlantic Gardener posts.
Ivy is not always a menace
Ivy reveals how nature is nuanced
Ivy goes green

 

 

                         

Outstanding new perennial

Heliopsis Burning Hearts_G022907
 The outstanding new perennial I grew this year was in the garden only by chance. Heliopsis ‘Burning Hearts’ was a trade from Ian Hodgson, Editor-at-Large for the UK weekly magazine Garden News, and it’s been exceptional. I passed him some new heucheras, he gave me the heliopsis.

This hardy bronze-leaved perennial is a form of the North American native H. helianthoides var. scabra which grows in much of the east and south of the USA as well as in Canada. A number of things impressed me about ‘Burning Hearts’.

I planted three young plants, raised from seed Ian had sown earlier in the spring, in mid May. The purple-bronze foliage was impressive straight away, the plants grew away well and in June they were in flower. They’re still flowering today at about 90cm/3ft, in spite of being partially shaded by the unexpected vigour of a new physocarpus (not to mention some rampageous climbing beans).

The bright, slightly golden yellow petals are rolled back gently from the dark eye, each one stained red-orange at the base, and are perfectly shown off by those dark leaves although the red centres fades as the individual flowers age. The plants have been dead-headed regularly and a long succession of stems have been cut for fiery bouquets. They’ve been amazingly productive.

Jelitto Perennial Seeds, who developed ‘Burning Hearts’, point out this is like a supercharged version of ‘Summer Nights’ with darker leaves and flowers in more dramatically contrasting colours. They say it’s been in the works in Germany since 2004 when, the catalogue from Jelitto reveals, “the idea for ‘Burning Hearts’ came in a dream”. Hmmm…

Gardeners in both Britain and North America can order seed of H. helianthoides var. scabra 'Burning Hearts' from Jelitto Perennial Seeds.


Testing new varieties in my trial garden

Part of my new Northamptonshire trial garden.  Image ©GardenPhotos.com

Back in March, I started to create a trial garden, a test garden if you like, in Northamptonshire. The idea was to grow new, recent and upcoming varieties so I can report on them from experience as well as grow cut flowers and vegetables. And that’s exactly what I’ve been doing.

During winter, my friend and helper (and artist) Carol Parfitt made a start by digging out bindweed and just about everything else that was growing in the plot leaving me a clear canvas. Then I made a series of rectangular raised beds using 15cm (6in) pressure treated boards, each bed is 1.2m (4ft) wide with 60cm (2ft) paths between.

The soil is good: old English cottage garden soil that has been improved with soot and compost for generations (not to mention, in earlier days) enrichment from pigs and chickens. Most of the new beds had soil improver added.

Things were a little late getting going, after all I was making beds long after planting and sowing time for many varieties. But as soon as each bed was ready, plants and seeds went in. Then I’d make the next bed, and more plants went in.

Weeding has been a big issue, the tiniest slivers of bindweed root will grow, after all, and moving soil around exposed the seeds of annual weeds which soon germinated. But regular weeding has kept them down and only what Brits call the Duke of Argyll’s Tea Plant (Lycium barbarum) has proved a lasting problem. More about that another time.

The trials of leucanthemums and cosmos and clematis and calendula have been fascinating. Leucanthemum ‘Real Glory’ (below) has been a real star. We’ve had more cucumbers and tomatoes and zucchini than we could cope with (though not enough lettuces). Cut flowers have filled our tables and windowsills and been given away and there’ve been successes and failures amongst the American varieties I’ve been growing in Britain for the first time.

Through the autumn I’ll be discussing some of the results of this year’s trials here and also on my Plant Talk blog for Mr Fothergill’s. Please check back and take a look.

Leucanthemum 'Real 'Glory'. Image ©GardenPhotos.com


New ways with phlox

PhloxEarlibeautyZenithDaughterofPearl
The tall and colorful American native summer phlox, Phlox paniculata, has been popular for more than a hundred years. In 1917 five hundred and eighty four (yes, 584) different varieties were grown in the USA and in 1907 one Scottish nursery alone listed well over three hundred varieties. In Britain, the Royal Horticultural Society currently has a grand total of 577 in its database.

Most of these have now vanished, but there are a number of impressive breeding programmes, many using other species in addition to P. paniculata, going on in both North America and in Europe. Hans Hansen at Walters Gardens in Michigan, with his Opening Act and Fashionably Early series, and Charles Oliver at The Primrose Path in Pennsylvania, with his Earlibeauty Series (above), are leading the way along with Gosen Bartels in The Netherlands with his Flame Series.

But some of the best known varieties of the summer phlox have arisen in another way – they’ve been spotted in the wild or in abandoned gardens by plants people with a good eye, and an appreciation of something special.

I’ve mentioned these in my article about phlox in the current issue of The American Gardener but space was tight so I thought you’d be interested in a little more detail. These were all chosen for their freedom from mildew, but it’s important to remember that mildew resistance is not constant. I’ve seen ‘David’, and ‘David’s Lavender’, completely ruined by mildew.

‘Common Purple’ Found in 1982 by Marc Richardson and Richard Berry, founders of Goodness Grows Nursery, at an old abandoned homesite in Greene County, Georgia. The plant was in full bloom, with no sign of disease or problems. It was introduced by Goodness Grows in 1984.

PhloxSpeedLimit45‘David’ Selected at the Brandywine Conservancy, Chadds Ford, PAennsylvania by nurseryman Richard Simon and the Conservancy’s Horticulture Coordinator Mrs. F. M. Mooberry for its unusually large white flower heads and freedom from mildew. ‘David’s Lavender’ is a sport discovered in 2002 by Kathryn Litton at ItSaul Plants, Georgia.

‘Jeana’ Found in the 1990s by Jeana Prewitt of Nashville, Tennessee, growing mildew-free among "many thousands" of mildew-covered wild plants. Introduced in 2001 by the much missed Seneca Hill Perennials.

‘Speed Limit 45’ Spotted by Pierre Brunnerup, in the company of Allen Bush, by the sign on the roadside near Bush’s nursery in North Carolina and seen to be mildew free. Propagated by Bush and introduced in 2003.

These are exciting time for phlox enthusiasts, with so many new introductions. Those such as the Earlibeauty Series, with no P. paniculata in their background, seem best placed to remain mildew-resistant in the long term.

* Thank you to Charles Oliver and Allen Bush for the pictures.


Chocolate cosmos alive and well in Mexico, not extinct!

Chocolate cosmos growing in the wild in Mexico. © Universidad de Guadalajara

Since the chocolate cosmos, Cosmos atrosanguineus, began to be widely grown in the 1980s we’ve all assumed two things: that it was extinct the wild and that there was only one clone grown which never set any seed. Well, that’s what the Royal Botanic Gardens at Kew and others told us. They even participated in a plan to reintroduce it to the wild. It was all part of the mystique attached to this captivating chocolate-coloured and chocolate-scented plant.

Now, it turns out, Chocolate cosmos has been growing happily in Mexico all this time, and in a number of different locations. So it has no need of re-introduction. And, in New Zealand, chocolate cosmos has been grown from seed since 1990.

Mexican botanist Dr Aarón Rodríguez and his team found eleven relatively recent records of C. atrosanguineus, the earliest of which was from 1986, and the locations mentioned in the records led them out to find the plant in the wild. Dr Rodríguez told me: “The populations are quite numerous. Plants grow in mixed pine and oak forest.” They were found in three different Mexican counties.

From around the same time Dr Russell Poulter, a geneticist in New Zealand, has been raising plants from seed and working to ensure that the plants resembled the original wild form.

Dr Poulter’s work is the origin of the seed raised varieties now available, ‘Black Magic’ from Jelitto Perennial Seeds, and an unnamed form from Plant World Seeds. At least one more is on the way. His plants have also led to the introduction of new cuttings raised varieties including Dark Secret (‘3013/01’), Eclipse ('Hamcoec') and Spellbound (‘Hamcosp’).

It’s a little baffling that these two fundamental facts have slipped us by all these years. But it’s great news that this lovely plant remains established in the wild and that new introductions are being developed from seed-raised plants.

* Find out more in the June issue of the Royal Horticultural Society magazine The Plantsman, where I describe the horticultural history of the chocolate cosmos from its introduction to Britain in 1861 to the confirmation of its status in the wild and recent development of new cultivars, including those raised from seed. Please subscribe here.
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A surprising field of red

A field of red campion, Silene dioica, with a few hybrids. Image ©GardenPhotos.com
Regular readers will remember that every so often I report on an unexpected crop that I’ve noticed growing in a field as I’ve driven around one or the other of my countries.

There was the field of phacelia and then there was the field of echium (viper’s bugloss). There's also been linseed, lupins, and more. But it’s been a while since I’ve found a new example.

The latest, spotted by friends near the historic local English village of Fotheringhay – where Mary Queen of Scots was imprisoned by Elizabeth I – turned out to be a field of, mostly, red campion (Silene dioica).

The acres of vivid magenta pink flowers are impressive but even a glance reveals that it’s not that simple. Red campion is a common British wildflower found on roadsides and in woodland glades and along hedgerows generally in places that are not too dry and not too acid. It’s lovely, and there a few named forms – mainly with variegated or coloured foliage, double flowers or dwarf habit.

One of the many variants of Silene dioica found in the Fotheringhay field. Image ©GardenPhotos.comIn the field at Fotheringhay there were plants with pale and with dark flowers, with red calyces and with green, and with wide overlapping petals making a very colourful flower and with slender petals with spaces between creating a starry look. There were also plants with white flowers and plants with pale pink flowers.

The plants with white flowers are, or are derived from the widespread close relative white campion, Silene latifolia; those with pale pink flowers are the result of hybridising between the two to create a hybrid known as Silene × hampeana.

So, this Fotheringhay field features acres of noticeably variable red campion with a few plants of white campion (which were a little taller and a little later flowering than the rest of the plants) and some hybrids mixed in. But what was it all for?

As far as I know red campion is not grown for its oil so I presume that it’s being grown for its seeds which will be sold as wildflower seed and go into wildflower seed mixtures. But with those hybrids included in the crop, and not rogued out, the one thing buyers will not be getting is pure red campion.

But what a lovely sight this field is… Another reason to visit the historic village of Fotheringhay and stop for a meal or a beer at The Falcon Inn.


Happy 30th Anniversary to the RHS Plant Finder!

Plantfinder2017Cover
The 30th anniversary edition of the Royal Horticultural Society Plant Finder has just arrived. And let’s be clear: just because it carries the stamp of the Royal Horticultural Society does not mean that it’s of no interest outside Britain. On the contrary.

The Plant Finder does two things and, in fact, it’s the one that’s not hinted at in its title that has universal value. Because, in order to establish which plants are sold by which nurseries, the names of the plants have to be standardised otherwise the same plant could be listed under three or four different names. And it’s the up-to-date determination of the correct plant names that’s so valuable across the globe. (The Royal Horticultural Society Plant Finder also tells you where to buy every one of the 72,000 plants listed.)

A team of Royal Horticultural Society botanists make decisions on names based on the latest research around the world and in consultation with experts everywhere. And the RHS has become more conservative, over the years, only this year determining that the hardy perennial sedums belong in their own genus, Hylotelephium, a change made in North America some time ago. But this up-to-date standardisation of the names is what makes the book valuable on all continents.

One of the features of this 30th anniversary edition of the Royal Horticultural Society Plant Finder is a range of contributions on the subject of the unique legacy of the 30th anniversary edition of the book. And one of the contributors is – me! I was asked to pick five plants included in the Plant Finder that I couldn’t do without. I chose a snowdrop, a hellebore, a sweet pea, a heucherella and a physocarpus.

Expert plantsman Tony Lord, who supervised the clarification of the plant names from the Plant Finder’s early days until soon after the RHS took it over, has included a history of the book but there’s one thing that he hasn’t mentioned. Eight years before the very first edition of the Plant Finder in 1987, I myself set out to produce exactly the same book. I had the support of leaders at Kew and the RHS and from one of the top British garden book publishers. So, early in 1979, I asked all the mail order nurseries I knew about across Britain and Ireland to send me their catalogues and I began collating their listings into a database from which the book would be produced.

I was living in Dublin at the time but no sooner had I set about acquiring catalogues than there was a postal strike – which lasted for eighteen weeks, that’s almost five months! And, of course, back then there was no internet and everything was done by post. So the whole project, which of course depended on being up to date, fell apart. And then I got a job as writer on the late lamented Practical Gardening magazine, hired by the influential UK TV gardener Geoff Hamilton, who was the magazine’s editor, and there was no time to revitalise the project.

Fortunately, Chris Phillip, his partner Denys Gueroult, and Tony Lord, with whom I trained at Kew (and who, let’s not mess about, usually beat me in the weekly plant identification test by a point or two…), made the Plant Finder the invaluable reference that it is today. Frankly, they did a better job than I would have done and I salute them and their RHS successors.

Every gardener, every plantsperson across the world, every nursery owner and propagator, every garden writer, every plant breeder - everyone with a serious interest in plants - should have the latest edition of the Plant Finder on their shelf. It’s that simple.

Order the 2017 RHS Plant Finder in the Britain and Ireland

Order the 2017 RHS Plant Finder in North America

Check out the Plant Finder's predecessor, the Plant Directory, produced by the Nottinghamshire Group of the Hardy Plant Society.


Roadside orchids

Pyramidal orchids (Anacamptis pyramidalis) growing on an English roadside ©Plantlife
A few days ago, friends here In Northamptonshire reported on some orchids they'd found. They were growing in the grass on a roadside along a very quiet country lane. They thought there were about forty early purple orchids (Orchis mascula), so I went up to take a look.

Sure enough, there they were (below) – about sixty five of them as it turned out - scattered through the long grass, their vivid colours standing out from quite a distance. They were all together, none for miles on either side. Lovely.

Early purple orchids (Orchis mascula) growing on a Northamptoinshire roadside.And it so happened that this find coincided with the a new burst of publicity for the campaign by Plantlife, the British plant conservation charity, aimed at protecting the plants growing on Britain’s roadsides. [Their website helps Brits ask your local council to protect roadside plants.]

Just a mile or two away plants of the bold tawny spikes of the uncommon parasitic plant, the knapweed broomrape (Orobanche elatior) grow on their only host, the greater knapweed (Centaurea scabiosa), along another quiet lane along with literally miles of meadow cranesbill (Geranium pratense)

Close to home over in Pennsylvania, I’ve noticed that roadsides are often the only local location for a number of interesting plants. The only clumps of false Solomon's seal (Maianthemum racemosum) (below) that I’ve seen nearby are on roadsides and I’ve also noticed more may apple (Podophyllum peltatum) and Dutchman's breeches (Dicentra cucullaria) along roadsides than anywhere else.

Partly, I presume, this is because the deer tempted to eat roadside plants are more likely to be killed by traffic and so the plants are more likely to flourish.

The key factor, of course, is mowing. Just a few hundred yards from those early purple orchids the roadside grass has been shaved like a suburban lawn. Why?! Once a year is ideal, unless the mower turns up at flowering time; mowing too early can prevent flowering and seeding and debilitate the plants. In many areas of Britain, local councils are saving money by mowing less and in some areas special marker posts are used to warn the mowers off.

And then, today, the Journal of the Hardy Orchid Society arrives and there’s an article about a stretch of roadside in Essex, east of London, which is packed with orchids. Along a busy, relatively recently constructed road, there are 350 bee orchids (Ophrys apifera) and 250 pyramidal orchids (Anacamptis pyramidalis) - a dramatic increase from 50 bee orchids and 60 pyramidal orchids six years ago. Much of this increase is down to reduced mowing brought on by budget cuts.

So, when you’re stopped in traffic, look out of the window and see what you can see. When you’re a passenger, keep your eyes peeled. But please, when you’re driving, keep your eyes on the road!

  False Solomon's seal (Maianthemum racemosum) growing on a Pennsylvania roadside=


The foxglove revival

Digitalis Goldcrest (left), Knee High Lavender and Foxlight Ruby Glow
Almost two hundred years ago Alexander Campbell, curator of the Manchester Botanical and Horticultural Society’s Garden, crossed a foxglove and a gloxinia (Digitalis grandiflora and Sinningia speciosa) to create what was known as Campbell’s hybrid foxglove.

It looks a little like a rusty D. grandiflora (below, right) but pollen from another foxglove - D. obscura, perhaps? - must have achieved the fertilisation that pollen from a gloxinia could never manage.

The first genuine foxglove hybrid between, D. purpurea and D. grandiflora, was made in 1849 but the seedlings were all sterile and it was not until 1924 that two hybrids that are still grown today were created at England’s John Innes Horticultural Institution: D. × mertonensis and D. ‘John Innes Tetra’.

Campbell's Hybrid Foxglove from 1825, said to be a cross with a gloxiniaSince then a large number of hybrids between different foxglove species have been created although, sadly, many have been lost including an interesting range created by the short lived Europa Nursery (anyone know where the owners, Tim Branney and Adam Draper, are now?).

Now, digitalis breeding is enjoying a bright revival with new hybrids being developed on both sides of the Atlantic. Goldcrest (‘Waldigone’) (above, left) was one of the first recent hybrids to make its mark. Three different breeding programmes in The Netherlands, in Suffolk (UK), and in Michigan, bring together the familiar British Native foxglove, D. purpurea, and D. canariensis from the Canary Islands. Foxlight Ruby Glow (‘Takforugl’) (above, right) is one of them. And, please, both parent plants are Digitalis. Let's not mess around with creating an imaginary new genus – Digiplexus.

Two new series of prolific dwarf hybrids are also just coming on to the market, the very short Knee High Series (‘Knee High Lavender’ above centre) from England and ‘Lucas’ and ‘Martina’ from The Netherlands.

I’ve recently published a long piece about the history of foxglove hybrids, from that early attempt using pollen from a gloxinia to the very latest developments. It appears in the current (March) issue of The Royal Horticultural Society magazine The Plantsman.

You can read my piece on foxglove hybrids online, but please take a moment to subscribe to The Plantsman: you can subscribe to The Plantsman here.