Layering shrubs and the joys of bedding plants

Pretty, cream-edged leaves of Castanea sativa Argentomarginata

It has been so hot lately that for light relief I have been doing some weeding in the shady area I call the Oriental or Woodland Garden. One of the delightful plants we grow there is not at all oriental, a variegated Chestnut, currently a very healthy looking bush. Removing weeds from around it I considered trimming up some of the lower branches but on reflection decided to use them as layers. I really like layering as a technique, mostly because it is completely fool-proof, and we have propagated many plants in the garden this way.

My experience with layering goes back to my youth, when I worked at the Royal Gardens at Windsor. A large proportion of these gardens were developed under mature Oak trees and as a result leaf-raking was a major activity in our lives for six months of the year, or so it seemed. Some of these leaves were taken to stacks to slowly break down, to be put back into the ground as soil improver. Huge quantities were just raked onto the shrub beds, where they acted as wonderful mulch. This mulch also provided ideal conditions for shoots to root, having been covered in the process. I would often find nicely established layers of rare and unusual Rhododendrons and other shrubs around the gardens……one or two of these found their way back home to Cornwall.

Layering is a long-established, if slightly old-fashioned, commercial propagation technique for a number of plants, still practised for species which are slow or difficult to root. It is useful when a nurseryman requires only a few specimens of a particular tree or shrub, or when large plants are wanted quickly. Layer beds may be established to achieve this, producing plants by systems such as Simple, French, Serpentine or Tip Layering, depending on species. Fruit tree rootstocks are commonly produced by Stool layering.

Marigold Golden Puff from Suttons, next to self-seeded Verbena bonariensis

Here at the Academy, I laid down a shoot of our Chestnut into a hole I had dug close by, bringing it up again in a way that formed an elbow approximating a right angle. Soil was packed down on top, this bending interrupting the flow of sap and inducing root formation. In the past I have done the same with Cotinus Royal Purple and Viburnum x. hillieri ‘Winton’, and used other forms of layering with Wisteria, Rubus and many other subjects. I also use it to train plants like Lavender and Santolina, bending and earthing-up a branch to push a shrub in the direction I wish. These layers could be removed and sometimes they are – they make nice presents – but often they are just left in place to increase the size of the shrub.

A pot full of Coleus Kong

We have grown large numbers of bedding plants this year, knowing the garden would be disturbed by the installation of the swimming pool. These are now starting to flower, later than in the village streets and park, but they have better facilities than we do. I like to grow small numbers of a wide range of bedding so our annual parcels from the likes of Suttons and Thompson& Morgan are always an event. Gazania Daybreak Tiger Stripe (Suttons) is one of the earliest in flower in the front garden while Antirrhinum Axiom and Busy Lizzie Double Carousel from T&M have just started in the pool-side bed at the back. Sweet Pea  Prima Ballerina, grown over a metal climbing frame, has kept the house in flower for a while now. Also from T&M, Coleus Kong mix is at its best with us when well fed in a pot, but less good in the poor soil near the pool. Sutton’s Marigold Golden Puff is just beginning to look impressive, alongside the ornamental, purple-leaved Millet Purple Baron. There will be many more to report on as the season progresses.

EBay plants and vermiculite by post

A pity there are not many gardens centres like this in France

Back in the UK we used to take garden centres pretty much for granted. We had a dozen or more within a short drive of our home, ranging from small privately owned businesses to impersonal sheds like Wyevale. At the top end there were places you could get lost in for the day: destination centres, as they like to call themselves: Poplars Garden Centre of Toddington, Dobdies in Milton Keynes, Roger Harvey Garden World or Van Hage at Great Amwell. You could more or less buy whatever you wanted, whenever you wanted it, unless my absence has fogged my memory with a rosy, horticultural glow.

Last week I wanted to sow Geraniums Moulin Rouge from T&M. I like to top the compost with Vermiculite after sowing, to retain moisture while still providing plenty of air to the seed. We drove to the local garden centre, and then another, to try to buy some, but there was none to be found. Back at home I resorted to the internet and found that gardening forums serving the ex. pat British gardener were full of requests for vermiculite suppliers. In the end I found the product at a reasonable price on EBay and it arrived today from a company in N.E. France.

Cortaderia selloana Cool Ice on arrival showing variegated foliage.

The trouble with EBay is the delivery charges, which can add a considerable amount to your purchases (in fact, years ago I was buying things regularly from a supplier in China; the articles cost very little but the postage could be ten times as much!). This company wanted more than I thought reasonable for postage and packing but would discount if you bought more than one item. I happily selected Cortaderia selloana Cool Ice for a total bill little more than if I had bought the vermiculite alone. Cool Ice is one of a number of Pampas Grass varieties trialled by the RHS in 2007-2009, features white leaf margins and is said to be compact. It did not receive an award of merit but availability is one of the criteria. I have found very few references to this variety so I am excited to see how it performs in our garden.

The Pampas Grass arrived in good condition, a well grown plant in a 3L pot. Plants by post have a reputation to be on the small side but this was not the case with the supplier, http://www.boutique-plante-nature.fr/. This is not the first time I have bought plants via EBay, a practice which, I can see, might cause a horrified reaction from my gardening friends, but so far, so good. I have on the other hand, had plenty of issues after buying plants from nurseries at garden festivals and many more with the popular gardening catalogue companies in France.

My next chance to see some of the best nurseries in France gathered in one place will be the forthcoming Salon du Vegetal show in Angers in February. I am trying to organise my life so that I can visit, but life is so busy, it’s not easy these days.

Loire Valley gardens and the first seed sowing.

We are hardly into January and already it feels like spring: we are getting busier on all fronts. There has been such interest in our study tours of the Loire Valley that I have been panicked into resuming work on a web site I started last year – Loire Valley Gardens- in which I describe the gardens of the region, listed by department (county).

Loire Valley Gardens La Chatonniere page

This web site started its life programmed in a heady mix of Flash, html and css and was so complex I had to give it up as beyond my capabilities. I eventually settled on a far more simple style and, just as importantly, a more straightforward coding method, but wasted so much time with the first version that I ran out of time to complete it.

At the moment I describe 15 gardens of the Loire valley on the site, with the gardens of the chateau La Chatonniere my latest. This is an amazing place with twelve themed gardens – the French do like a theme, the artier the better – surrounding a beautiful Renaissance castle. I won’t say more here: you can look at the details on the site if you are interested http://www.loirevalleygardens.com/chatonniere.html . I am looking forward to seeing how the gardens are progressing in 2012 and to learn if they have plans for more themes. The last major development was in in 2008 when The Garden of Luxuriance was built to feature 400 David Austin roses, adding to the collections of roses displayed in other areas.

Soon Loire Valley Gardens will list and describe thirty-four gardens. As I revisit these gardens and discover more the site will continue grow and I hope this will prove a useful resource for clients, students and others interested in this fascinating region.

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The first of my seeds are now sown and in the propagator: Begonias, Antirrhinums and Coleus, all absurdly small seeds which are applied as a ‘dust’ to the surface of moist compost. There are around 88,000 Begonia seeds per gram making them difficult to see and to sow, even with modern, sophisticated machinery. In my days as a grower we had a machine which would sow them from a series of units dropping four or five at a time and with the bounce as they hit the compost created a pretty good covering of a seed tray. Begonia seed is very expensive but we also sold plants in compost plugs and it was important to only have one or two seedlings in each if we were to make a profit. For these we resorted to pelleted seed, each grain being given a coating of clay which allowed our seed sowing equipment to place them one by one at the centre of each plug. All clever stuff. One of the Begonia varieties I sowed this week was pelleted seed: Torbay Mix, from Suttons.

Antirrhinums are large by comparison to Begonias – 7,500 to the gram and Coleus is around the same, but they are still hard to work with. When my order of Vermiculite finally arrives from EBay I shall get the Geranium seeds done – 200 seeds per gram – even I can see these!

An unusual task this week will be to dismantle the seasonal display of foliage and berries we constructed in the conservatory for Christmas; I have my eyes on the berries of the Butcher’s Broom and plan to sow them under the Sequoias. The branches of this plant were collected from plants found in local woods, so I have every hope they will do well.

Ruscus or Butcher's Broom

If the squirrel leaves them alone we can expect a patch of these adaptable plants for next year and by sowing a large number of seeds hope to have both male and female plants, giving berries for many a Christmas to come.

January gardening, sowing and lighting systems.

Some of you may know that in a previous life I grew seedlings and young plants, hundreds of thousands of them, for the bedding plant industry. Our nursery, Opax Farm in Headley, on the Hampshire / Surrey border, was a state-of-the-art affair consisting of 6 ½ acres of glasshouses on a nine acre site. It had computers controlling everything from the ventilators which opened according to wind direction, the percentage of CO2 in the air, the pH of the water and of course, the air temperature. In case anything broke down we had two of everything and, in event of a power failure, a generator, which could have lit a small town, automatically kicked in, powered by a huge, Rolls Royce engine. This piece of equipment was thoroughly tested in the week we took over, when a passing hurricane cut off our valley from the rest of the world for more than a week!

Begonia seedlings

These days my growing is a little less high tech but I will shortly be sowing Geraniums and Begonias in the propagator I have set up in the attic and I’m concerned that they may not receive the light they need to grow well. But why do we need light in plant cultivation? The major horticulture issues are:

• photosynthesis — converting light, air and water into carbohydrates and oxygen to support plant growth.
• chlorophyll synthesis —building the plant cells that perform photosynthesis.
• photoperiod — sensitivity to the length of day.
• phototropism — movement toward a light source.

Back in my days at Opax Farm we had a number of lighting systems for a range of plant growing tasks. Strings of ordinary tungsten bulbs had been used by the previous owners to control flowering in crops like Chrysanthemum. This plant requires a very specific day-length to flower and if you need to produce flowers throughout the year you will at times have to completely block out the light, while at other periods of the year create light. Plants that bloom in the winter, such as Christmas cactus, poinsettias, gardenias and chrysanthemums, don’t flower unless the nights are longer than the days. They are referred to as long-night plants and for the most sensitive long-night plants even one minute of bright light during the night is enough to prevent them from blooming. In general, long-night plants need a maximum of 10-13hours of light per day to flower.

Last year's Begonias

Plants that typically bloom during the summer don’t flower unless the nights are shorter than the days, so they are called short-night plants and include many bedding plants and vegetables. Short-night plants need 14-18 hours of light per day in order to flower. Other plants bloom regardless of the length of the photoperiod, so they are called night neutral plants. Many of these plants are sensitive to temperature variations however, and bloom when the nights are cooler than the days. For early growth and development, plants need the opposite photoperiod: young long-night plants should have long days for the first month or two to encourage full growth before blooming, while young short night plants should have short days. Day length can be manipulated for other reasons, such as the selection of male or female plants early in the cycle, by inducing flowering.

We had a number of growth rooms at Opax in which we germinated seed in optimum conditions. Some plants need light to germinate while others prefer the dark. Trays of recently sown seed went into different growth rooms depending on their requirement for light and heat. With sufficient light levels it is possible to grow plants without any natural light.

Greenhouse lighting

Several of the plants we grew were needed early in the season when light levels are low: we started sowing Begonia sempervirons for bedding plant growers before Christmas. These plants were placed in an area of the greenhouse where we had lighting to supplement that of the sun, ensuring good, strong, compact growth at the darkest time of the year. Attempting the same thing in our attic later this month, I have assembled a lighting rig to increase the light levels for the seedlings I will grow there. This structure incorporates a number of domestic halogen lamps which I trust will provide a useful boost in light levels but be inexpensive to run. I’ll let you know how we get on. I did have a quick look at the new LED Grow Light units currently being promoted for indoor growing but the cost was far too high for me to justify on my hobby, so my Heath-Robinson construction will have to do for now.

Several Garden Design Academy courses look at the complex subject of plants and light, also considering the types of light most suitable for horticulture by cost, light spectrum, heat emissions and other factors. Some of our RHS courses and the Certificates / Advanced Certificates in Horticulture, are particularly good on this.

Something for nothing again – Thompson & Morgan seeds.

I’m a great fan of growing plants from seed and have been using Thompson and Morgan in the UK for years. Now based in France, we use the T&M Worldwide site at http://www.tandmworldwide.com from which this screenshot is taken and who have agreed to provide a prize to readers of this blog.

On offer is a £20 parcel of seeds including the T&M Flower of the Year and Vegetable of the Year as illustrated here.

To win this box of goodies please “Like” this blog post and leave a message including your email address, name and address and a winner will be picked out of the proverbial hat at the end of the month.

Thompson and Morgan would like to send you occasional newsletters and offers but please tell us if you do not want this and we’ll make sure you are not bothered.

I already have seedlings of Sweet Pea Ballerina but there is still plenty of time yet. The rest of my sowing will start in January, with the Begonias and Geraniums, using a heated propagator bought from T&M last year.

With the co-operation of suppliers I hope to regularly run competitions and give-aways, so have a go at this, our first and watch out for more in future posts.

To have a chance of winning this box of seeds please “Like” this blog post and leave a message including your email address, name and address and a winner will be picked out of the proverbial hat at the end of the month.