For something like twenty years now I have written easy to read botanical articles that have been published in magazines, newsletters and bulletins of various societies. If you feel that your group/society/ club etc. may benefit from such articles please contact me. My fees are reasonable.

In May 2001 I finished writing a book on western North American alpines. It features some 54 genera, including all the popular ones, around 500 photos and several maps. Cultivation and propagation techniques have been included within each chapter as well as an individual cultivation chapter. The title is "Alpine Plants of North America" and is described by Timber Press as an Encyclopedia of Mountain Flowers from the Rockies to Alaska.

It was published in late 2002 and details can be seen on the home page of this web site.

Below are two illustrations of my work. Both are copyright and all enquiries for reprodution in any part or whole must be made to me.

I grow all the western North American Campanula species, mostly in pots and with varying degrees of success, but I also grow many European species. Some of these are not just suitable for exhibition but also grow quite happily outdoors in an alpine raised bed or trough. Wearing my nurseryman's hat, I have to be able to propagate them-sometimes in large numbers, since they are very popular. By "popular," I don't mean that the average customer stopping at my sales table would necessarily buy one of these species; it's the grower looking for something a little out of the ordinary who picks up one of these plants with a cry of delight and thrusts money into my hand. I take pride in being the only mail-order nursery grower in the United Kingdom presently offering these campanulas.

Campanula choruhensisis is a species that some of you may already have. It's a wonderful plant and easy to grow--almost as easy as the closely related C. betulaefolia. The leaves are deep green and hairy, and its white flowers, sometimes flushed with pink, can be huge. Plants vary in growth habit: some have a number of fairly short stems branching off and hanging down, carrying clusters of as many as 6 flowers; others grow upright, with the bells massed together in a huge bunch. Unfortunately, though they look well in pots, in the alpine bed the flowers that hang down tend to be spoiled by dragging on the ground. In her 1993 Rocky Mountain Rare Plants seed catalog, Gwen Kelaidis described this species as "sensational," and she wasn't kidding. At the AGS Summer Show South in 1997, both my plant and one grown by another member of the Wiltshire AGS group were awarded a Preliminary Commendation by the Royal Horticultural Society Joint Rock Garden Plant Committee, and a note on this campanula appeared in the Quarterly Bulletin of the Alpine Garden Society (65.4:434-435, Dec. 1997).
My original plants were grown from seed purchased from that catalog, soon after C. choruhensis was described. Josef Halda collected it at that time, and a year later another Czech seed collector, Vaclav Holubec, also started to list this species. It comes from Tortum and Kargapazari Dag in Turkey, where it inhabits rotten schist and volcanic rock crevices at elevations around 2000 meters (6500 feet); it loves a cool northern exposure.
Propagation is straightforward by seed, which is quite abundantly set most years. Like most campanula seed, it is very fine and must be collected from the base of the dried capsules before it is dispersed to the four winds. Sow your seed thinly, or you will end up with masses of seedlings which just love to damp off. I sow mine on the surface of a pot of compost topped with grit, which allows it plenty of light to speed germination. Seed-grown plants vary in growth habit from upright to drooping, and leaf size may also vary; nevertheless, so far all my seed-sown mature plants have the large flowers of their parents. If you have a particularly nice specimen that you want to duplicate, you can take cuttings in spring when the new shoots are growing vigorously.
Campanula choruhensis grows well in a range of soils despite the rigors of its native habitat. After flowering in May or June, the stems die back in autumn to a central rootstock, and during winter plants growing outside look quite bare. In the alpine house, however, plants usually have a little green showing.

Campanula hercegovina 'Nana' is an absolute gem for a trough. The small, bell-shaped, deep lilac flowers are borne on slender, decumbent stems 7-10 cm (3-4 in.) long. These stems are branched and arise from a woody rhizome. The plant slowly forms a clump, never becoming invasive. It dies back in winter and reappears in late spring. Flowering is from late May to June and sometimes continues sporadically into autumn, especially in the alpine house or coldframe. It is a very easy plant to grow, either in an alpine bed or in a trough. In the wild, C. hercegovina inhabits limestone crevices and cliffs in Bosnia-Hercegovina.
I inherited my original plant in 1990 from a nursery that was going out of business at the same time as I was starting up, and it is still going strong in one of my raised beds, now about 15 cm (6 in.) across. Propagation is very easy: literally pull the plant apart and pot up the rooted pieces. This can be done from the time the new shoots appear above ground in spring right through the growing season until early autumn. In the nursery, it is far easier to grow half a dozen plants in plastic pots and use them for propagation stock than it is to keep digging up the garden specimen. In this way I can divide the stock plants at least three times in one year. I have never found any seed in the capsules, but several self-sown seedlings have appeared in pots where sale plants had been kept in the alpine house. These grew very quickly, flowering and filling a 7-cm-square (3-in.) pot in the first season.

My third choice, Campanula jaubertiana, is a lovely, free-flowering, vigorous species which has intense violet-blue flowers on stems to 12.5 cm (5 in.) tall. (A photograph of it also appears in the Quarterly Bulletin of the Alpine Garden Society 63.4:379, Dec. 1995.) This is another ideal plant for the trough, if you can keep the slugs at bay. It also revels in growing in pots, and in the UK it is often exhibited at the summer shows.

 

Photo Robert Rolfe

 

I obtained my first plant of C. jaubertiana in summer 1994 as a swap after I saw it exhibited. From that one plant, I have since produced more than 100 plants for the nursery, and the original is still good enough to exhibit. Although the species was described as long ago as 1868, at the time I obtained my plant it had just been reintroduced to cultivation. It is another a limestone-dweller, this

time from the screes and rock crevices of the

central Pyrenees at over 2000 metres (6500 feet) elevation. There are reports that it also grows in isolated sites on the high southern slopes of the foothills of the Spanish Pyrenees and at one station in Andorra; at the latter it is identified as Campanula jaubertiana subsp. andorrana. Although in the wild it normally flowers from July to August, in cultivation it blooms about a month earlier.
Propagating C. jaubertiana is even easier than increasing C. hercegovina. In fact, it just cries out to be split up. Very vigorous, it dies back in winter, even in an alpine house. It comes into growth very early in spring, and at that time I knock the previous year's unsold plants out of their pots and pull them to pieces, using scissors to cut off any piece of stem that has a root on it. All pieces are then repotted and put into a coldframe. The larger pieces quickly grow to a size for planting out, usually by late spring, and the smaller pieces later the same year. Right up to October, whenever any unsold plants show tufts of new growth around the edges, I divide them in the same way, so I am never without this jewel. My plants have never set seed, and I have not heard of other plants doing so either.
Cultivation of C. jaubertiana is simple in a scree or a raised bed with very gritty soil, with some shade on hot summer days. In winter, outdoor plants usually disappear below ground, but those in the alpine house stay green and break into growth earlier. With alpine-house specimens, it is best to clip over the stems in fall, removing the spent flowerheads and any stems that appear dead. A gritty compost with lime in it suits this plant down to the ground. Slugs are the worst problem it encounters. If you haven't grown this plant yet, then give it a go!

Some years ago I was browsing over a nurseryman's sales table and spotted a campanula I didn't know much about: Campanula petrophila. It looked promising, and anything unknown is worth a try. This has turned out to be another wonderful species for the garden. It comes from the Caucasus, where it grows in cool rock crevices at around 3600 meters (11,700 feet), forming tight clumps of small, ovate basal leaves that are sometimes toothed. The stems are prostrate, to 10 cm (4 in.) long, and carry clusters of large, blue-purple, bell-shaped flowers.

If you grow C. petrophila under glass, as I did at first, you will find that the stems elongate and the charming compactness is lost; but put it outside in a trough, gritty alpine bed, or sand bed, and it becomes a wonderful alpine bellflower. As soon as it got into one of my alpine beds, a dramatic change took place. As you can see from the photo, it made a tight clump with huge, almost stemless blue-purple bells.
This is not one of those beautiful plants that flower once and die with no possibility of propagation. In spring or fall, dig it up, remove rooted pieces, and pot them up. If you do this in spring, you will have a small potful by fall, ready to split again. There has to be a downside, though, and once again it's the slug problem. Nevertheless, C. petrophila increases quickly enough to keep it going in several places around the garden, and it's certainly worth the trouble.
Finally, the choicest of these five gems: Campanula zoysii, the campanula that is always mentioned by rock garden writers and speakers discussing campanulas for troughs. (I always suspect that the majority of these people have never grown the plant and are just cribbing from other authorities, but perhaps I'm wrong.) I grow a clone of C. zoysii which-luckily for me-is vigorous and free-flowering.
Campanula zoysii comes from the southeastern European Alps, where it grows among limestone rocks. Its unique and lovely flowers are crimped at the mouth, making it very difficult for bees to enter. Last year (and by good fortune, after the shows), I noticed two different types of bees flying around my plant: a small one that burrowed into the closed end of the flowers to obtain the pollen, and a very large one that must have thought "To hell with all that!" and just drilled a hole straight through each flower. Half an hour later, all the flowers on my plant possessed an extra hole. No seed was set, which made it a pointless exercise as far as I was concerned.

 

Having whetted your appetite for the typical C. zoysii, I'll tell you about one I obtained in exchange for Androsace bryomorpha. It is a white form with the clonal name 'Lismore Ice'. This plant was raised by the nurseryman Brian Burrow from wild-collected seed from the Julian Alps distributed through the AGS seed exchange (don't look so amazed!) about 13 years ago. It's an exquisite plant, documented in a photograph in the Quarterly Bulletin of the Alpine Garden Society (57.1:82, Mar. 1989). Much more compact than the usual blue form, it also has much smaller leaves. The tips of the leaves are slightly yellow, but this is a natural characteristic of the plant and not, as some writers have said, a sign of chlorosis. I have yet to grow this plant in a trough open to all the ravages of the weather and slugs, but I have no doubt that it would be fine outside, provided ravening mollusks were kept at a distance. Like the blue form, it increases by underground runners.
Propagation of these forms of C. zoysii is easy, either by cuttings in spring or as described above for other campanulas with underground runners. When shoots appear around the edge of the plant, don't be frightened of it; take it out of its pot and remove any rooted pieces, potting them up as described above. The white form is much slower to increase than the blue and takes longer to build up into a large plant. It seems that continual disturbance and a deep top-dressing of grit encourage it to survive and produce side shoots. From the small plant I obtained in 1995, I had propagated enough plants two years later to list 'Lismore Ice' in my autumn catalog. If it hadn't been for that swap, 'Lismore Ice' might have been lost entirely; as far as I know, that plant was the only one in existence. It was gratifying when I was able to return one to Brian Burrow, the original raiser. This is what conservation is all about. It has now become more widely available.
The blue form of C. zoysii builds up over about three years into a power-packed plant that blooms tremendously, hardly any rosette without a flowering stem. Unfortunately, after flowering, these stems and their rosettes die back, sometimes resulting in the death of the entire plant. You must make it a priority to propagate C. zoysii before this happens so that you have smaller plants coming on to replace the "big one"-which inevitably dies.

 

This article appeared in the North American Rock Garden Society 'Rock Garden Quarterly' Spring 2001. Volume 59 No.2

 

 

 

JUST ONE MORE

In the late 70's that well known seed collector John Watson issued a list of seed from his Turkey expedition. Of the Campanula seed that I bought from him, Campanula ledebouriana proved to be a superb plant. It eventually earned me a Certificate of Merit at one of the AGS shows. `Murphy's Law' being what it is however, the plant promptly died without me ever having propagated it. You can imagine my excitement when I spotted in Josef Halda's 91-92 list Campanula ledebouriana pulvinata was being offered. This was described as 'a little known cushion Campanula'. It certainly was, and luckily up to now, still is. (Murphy's Law will now grind into motion). I grew it in a pot for several years hoping that it would make a good show plant. Here it just about survived and last year decided it had to take it's chance outside. Imagine my delight that within a month of planting it out in a gritty limestone bed, it became a tight mound 8 cms across that flowered in early summer with very large violet blooms on just 5 cm stems. It must be the best cushion Campanula that I have ever grown. Now for the (almost) bad news. I turned my back one day in September and a slug chewed all the flowers, shoots and leaves to within 2 cms of the ground. It now once again resides in a pot in the alpine house where at present it is imitating a bunch of green/brown stems. In the wild it does not inhabit slug ridden gardens but grows in the Sevan range, little Caucasus, C.Armenia at around 3,200m.

Although I grew this plant from seed I had no chance to see if seed had been set for me due to the earlier visitor. However, I think that the best way to propagate it is cuttings in early spring. It grows from a tap root and I couldn't find any rooted shoots when I dug it up. It appeared to be extremely happy in my limey soil and I am only hoping that I can propagate it enough to distribute the fantastic cushion plant, Campanula ledebouriana pulvinata amongst my good grower friends.

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As a plantsman, I like to grow, exhibit and propagate unusual plants, yet as a nurseryman, I have to produce as many plants as possible in order to make a profit. Combining these two goals can make life very interesting. If I have only one plant of a rare species, then I consider that I have a duty to propagate and distribute it, if only to keep it in cultivation. From the profit angle however, I may as well produce as many plants as possible at the same time.

Underground Shoot Cuttings

Many of my stock plants are also show plants and occasionally there is a clash of interests between keeping a plant up to exhibition standard and propagating it for sale. In some cases, satisfactory cuttings can be taken from the edge of the plant. In others, such as Campanula piperi, C.zoizii, C.shetleri, and C."Joe Elliot", underground growth with roots attached can be used as cutting material.

Early Tip Cuttings

Many other plants are not so easy to propagate. Take, for example, that lovely shrubby viola from the Sierra de Cazorla in Spain, Viola cazorlensis. Thin stems with tiny leaves rise up about 4" and are topped with huge, pink-purple, long-spurred flowers. Although my plant has set seed on two occasions, there has never been any germination. Propagation therefore has had to be carried out vegetatively. All cuttings root very easily in sand and grow on well when taken as early as possible after growth commences in the spring. This enables new plants to have a long growing season and make a good root system before they go dormant. If you miss the first growth and take cuttings later in the year, they will root and grow but you will be disappointed the following spring when nothing emerges, the roots having died off in winter. Taking cuttings from the first growth produces a bonus, encouraging the plant to break out from the base bearing far more flowering stems, resulting in a much showier exhibition plant.
Another case in which taking early cuttings improves flowering of the stock plant is the Mexican phloxes. When I obtained my first cultivar, Phlox mesoleuca 'Mary Maslin', the only method recommended was root cuttings. However, I tried cuttings in sand from the first growth with great success, and the plant flowered profusely later. Now, all my Mexican phloxes are increased by that method. I do find that accidental root cuttings help with this group of plants. Where pots of stock plants are stood on damp sand during the season, sometimes green shoots appear out of the sand as the plants root down from the bottom of the pot and produce lateral shoots. These are gently removed from the sand and potted up.

Crown-and-Root Division

I have had one plant of Lewisia stebbinsii for twelve years (grown from ARGS seed sown in 1982). It has flowered well for me the last 5 years but has never set seed. How could I increase my stock? Seed from various exchanges, although listed as L.stebbinsii, usually turned out to be Lewisia longipetala. This year I tried a different, but simple method, that I had been using successfully in propagating good forms of Lewisia rediviva. In L. rediviva, I cut off the growing point in early spring, and then wait a year for new growing points to emerge from the caudex rim. The caudex and root are then sliced lengthways. Each piece with a growing point is treated with rooting powder or fungicide and inserted as a cutting. Once rooted, they can be potted up. My plant of L.stebbinsii, had made quite a wide carrot- like caudex with still only two shoots after a decade. In the autumn as these shoots started to grow, I took a deep breath, and a sharp knife, and cut the caudex and root lengthways. I treated the resultant raw root with hormone powder and potted up both pieces. They are now growing well. Although these plants are the same clone and possibly will still not set viable seed, I will not have any fears of dividing them again in the future.

Rhizome cuttings

A new corydalis is on the scene. Corydalis flexuosa, from China, is one of those plants that is a nurseryman's dream. It has beautiful blue flowers, grows at terrific speed and is propagated easily. Although it is normally grown in a leafy soil, put it into a sandy compost for propagation purposes. The plant appears to grow twelve months of the year, but it does slow down around July. Then the plant can be either dug up or knocked out of it's pot to uncover the horizontal rhizomes. Break these into small pieces and pot them up. Growth will soon restart, and in no time fresh fernlike foliage will appear above the surface, to flower next year.

Cuttings or Whole Seed Capsule

A New Zealand forgetmenot, Myosotis uniflora, forms a lovely dome with stemless, yellow flowers. It is reasonably straightforward in cultivation, as long as it is grown in very gritty compost. Sometimes this plant is shy to flower or to set seed. When it does, the job of prising seed out of the capsules hidden in the foliage can be very frustrating. Several years ago, with no seed available, I thought "nothing ventured, nothing gained" and took twelve cuttings, inserting them into sand. Although it was June, every one rooted, and by the following spring were of a saleable size. I contacted my New Zealand pen-pal with this information and she replied that this hadn't been tried at her local alpine nursery, in spite of it being a native plant and very much sought after. It had been assumed that cuttings would not take. Joe Cartman, in his book "Growing New Zealand Alpine Plants", said that this plant was easy to propagate, but it appears that seed, when available, had been the usual method. The ironic thing this year is that I sowed a number of seed capsules whole, as I could not retrieve any seed from my plant. Germination has been like mustard and cress. Each capsule must have held 3 or 4 seeds and the surface of a 6" pot is thick with seedlings. Potted on early, these grow on over the winter to form saleable plants by late spring.

The Carrot Shoot Trick

No doubt many of you grow Erigeron aureus "Canary Bird", but any seed that you sow from it will not produce dozens of "Canary Birds". This plant does not provide much cutting material each year either. I was given a tip from another nurseyman : In early spring, when growth is starting, take a sharp knife and be ruthless. Cut straight across, just at the top of the caudex - try it on a carrot first. After a few weeks, new growth will start from the edge of the caudex. A great many more shoots will appear than were previously growing and when long enough can be used for cuttings.

 

These are just a few suggestions that may enable you to increase your stock of unusual plants. I pray that no nurserymen are now reaching for the telephone to contact their lawyers, considering that I have given out trade secrets for free.

 

What Works with Convolvulus?

 

 

In the original article I finished with the following plea.

 

"Now can someone give me advice? Convolvulus boissieri, another Spanish species, is a wonderful silver mat forming plant with large almost stemless, white funnel-shaped flowers. I have tried over many years to produce an adequate number of plants to sell when taking cuttings. I have taken cuttings in spring and all have died off. I have tried bottom heat with no success. Cuttings taken in autumn have rooted after 9 months, but even then with only 25% success. Can anyone improve on this? I would love to make it available in larger quantities."

 

Since then I have found that layering works a treat, not only this plant but others. Phloxes and Arenarias for example can be quickly increased by layering.It does take a season or so for rooting to take place but the rooted pieces are larger than normal cuttings. If growing in a pot just knock it out and repot it lower than it was originally. Top dress with a gritty mix and grow on as normal. many of the sides shoots now under the top dressing will root and can be removed and potted on after about a year. If the plant is growing in the garden, work the gritty mix in and over the side shoots. Rooting wil take place in exactly the same way. In fact by just examining the outside shoots before you cover them you may find some rooted pieces anyway.

 

Spring 1994 NARGS Bulletin Volume 52 No.2

Updated 19th November 1999