Print Page | Close Window

Clematis House

Printed From: British Clematis Society Forum
Category: Clematis
Forum Name: Postings
Forum Discription: General chat and help about anything Clematis
Printed Date: 21 Sep 2020 at 9:02pm
Software Version: Web Wiz Forums 9.06 -

Topic: Clematis House
Posted By: digger
Subject: Clematis House
Date Posted: 21 Feb 2008 at 2:44pm
LOL hello to everyone, I am fortunate to have a new greenhouse arriving soon and I wanted to use it for keeping clematis, where can I find information about specific requirements for them like temperature,air movement etc.? or will it be okay to have it toatlly unheated? at the moment my cle,matis seedlings and cuttings are in my current greenhouse and they are taking up too much room , I will have electricity in the new greenhouse so I can use it for propagating cuttings.

Posted By: bcollingwood
Date Posted: 21 Feb 2008 at 5:12pm
Hiya Digger,
If you want to ring me let me know and I'll email the number.

B. R. Collingwood

Posted By: digger
Date Posted: 21 Feb 2008 at 5:46pm
 Brilliant Brian thank you so much for your kind offer I shall check out your website, I must say i wish I could have a 51 feet x 24 feet clematis house. I have sent you a private message.

Posted By: bcollingwood
Date Posted: 21 Feb 2008 at 10:48pm

Plants sprouting now in the houses, fortunately the days getting a little longer too.

B. R. Collingwood

Posted By: Nunn00123
Date Posted: 22 Feb 2008 at 12:13pm
I agree that generally no heat is required in the greenhouse, large vents with auto controls are essential.
Notes on propagation;


 Notes from a Workshop at the Alpine Garden Society meeting in 2003

Much has been written about hybridising and growing clematis from seed, but what to do when you have produced a plant worthy of further development, keeping for yourself, passing to friends, or ultimately passing on for commercial production. It cannot be expected to produce an exact copy from seed and therefore some form of vegetative propagation will need to be carried out, in order to produce some exact copies of the original plant. A few plants may be produced by layering stems to the ground, but where stems cannot be bent down air layering can be used. The method mostly used is to produce copies of plants from cuttings.

My first attempts to take clematis cuttings resulted in 100% failure, I found myself in a dilemma, as to whether I should give up this process or should continue until I was able to have a reasonable success rate. It took me several years of trial and a great deal of error, before I started to have acceptable results. It is rewarding, when I now get 100% take in a batch of cuttings, to think of how I struggled in my initial attempts. I still have my failures, but now it is more because of unsuitable materials taken at the wrong time of year, or of plants that refuse to produce roots or top growth together, e.g. C. texensis.

 1) Compost, equal parts, Fine Composted Bark (Cambark), or Melcourt Propogating Bark.

Horticultural Sand, or Silver Sand,

Fine seed grade Perlite.

Incorporation of 5% Slow release fertiliser to the above mix seems to help the process along.

Many other compost mixes are used for taking cuttings, but as a general rule the more misting that is carried out the more well drained the compost needs to be. The compost mix must be kept moist, but must not be allowed to become dried out or waterlogged.

2) Containers, I use seed trays. Many other containers may be used, but it is important to use containers that are about the depth of a seed tray, in order to exploit the benefits of bottom heat. The seed trays stand on a sharp sand bed, which incorporates heater cables and a thermostat which controls the temperature. Drainage of this medium must be very sharp, the bed incorporating a large number of drainage holes in its base.

3) Temperature, I aim to provide bottom heat at 20 degrees centigrade which seems to be the optimum temperature. Temperatures 5 degrees either side of this norm seem to be detrimental to optimum root and shoot formation.

4) Light, It is important to protect cuttings from excess light and temperature by shading from the sun. More light may be introduced where mist propagation is used,


but bear in mind that direct sunlight is likely to be fatal.

5) Humidity, The leaves and stems of cuttings must be kept from drying out, but must not become saturated. This can be achieved by the following methods.

Covering the cuttings with a plastic membrane to control humidity.

Plastic propagators may also be used, opening or closing vents to control humidity.

Shading membranes are also used, but this method will generally require additional misting to keep the air humidity levels at optimum levels. I have found that these methods work provided that you have time to check the humidity levels and adjust shading, open up membranes and hand mist to provide optimum humidity levels.

I now use an automatic misting unit, fitted with a (leaf) controller to control misting to a suitable level. Once set the unit will provide an optimum level of humidity no matter what the light levels are. Also a there is a cooling effect provided by the misting, which helps to prevent overheating in hot weather.

6) Protection from fungus attack. Cuttings are soaked in a fungicide before they are placed in the trays and the compost will need to be sprayed with fungicidal solution after the cuttings are introduced to the compost tray. Also if hand spraying is carried out fungicides will need to be incorporated in all or most of the damping down processes. I no longer soak cuttings in fungicides, but drench the whole tray of cuttings after sticking.

Note some fungicides have been found to be detrimental to the formation of root growth, none of the fungicides listed as suitable for taking cuttings are available to the amateur.

I now exclusively use a Traditional Copper Fungicide for all cuttings and spray with fungicide once a week, as there seems to be much less of a need to spray with fungicide when using and automatic misting unit. Note that some other fungicides will not be tolerated by New Zealand cuttings, when used at full strength. I have previously, successfully used these fungicides at half strength.

Note that since using mist propagation I rarely use fungicides after the initial drench.

7) Hormone rooting powder or gel may or may not be used, I use a Hormone rooting Gel (Clonex). Hormone gel or powder must be replaced at the beginning of each cutting season, as the effectiveness of these materials decreases with age and use.

Before use always pour a little rooting medium into a shallow container, I use a screw on plastic milk bottle top, which has been thoroughly washed and disinfected in bleach solution. After taking cuttings any excess rooting medium is discarded. This should keep the remaining rooting medium free of contamination.

8) Tools, A stainless steel container or glass jar for dipping cuttings into fungicidal solution. A small shallow container for hormone rooting medium. A number of curved scalpel blades and a handle, or a knife, I use an Opinel knife which I think to be the best shape for taking cuttings. Secateurs for roughly cutting material and a pair of small pointed scissors for trimming material ready for soaking in fungicide. A small dibber for dealing with soft or short material, I use a 80mm copper nail, but most material should be able to be pushed into the rooting medium without resorting to the dibber. A small A4 size Hobby Cutting Mat.

Clean all utensils and tools with a 5% Sodium Hypochlorite Bleach Solution. Note that a scalpel may be used for taking a few cuttings, but a knife is to be preferred for

taking larger quantities, but it must be very sharp. Invest in a Arkansas or Wash*ta slip stone and a leather strop and seek advise on how to get a really sharp edge on your

knife. A carbon steel blade is much better than stainless steel as it will sharpen and retain its edge much better, but steel must be protected from rust. A guide to the sharpness required is indicated when the hairs on your arm can be shaved. A blunt knife damages the tissue by crushing instead of cutting. I cut onto a hobby cutting mat, as my knife is too sharp to be used to cut against ones thumb.

9) Types of Cuttings.

Softwood (Semi-ripe) Cuttings. Inter-nodal Single node (node above compost level), Single node (node below compost level), Nodal Two node, Two node (Japanese style).Softwood (Semi-ripe) Inter-nodal. [Single node cuttings], where the node is positioned above the compost level [Fig. 1a], this is recognised as the normal commercial method in this country, which seems to work on 90% of clematis varieties.

Single node cuttings, where the node is buried below compost level [Fig1b], I have found this method reasonably effective for some of the species in the Viorna section, which are difficult to produce roots and top growth simultaneously and then to produce subsequent growth in the following year after the cuttings have taken.

Note bear in mind when taking internodal cuttings that the area around the node is the most conducive to producing roots, therefore keep cuttings no more than 25mm from its node.

Two node (Japanese style) cuttings [Fig.1c], I use this method for evergreen varieties, New Zealand Clematis, and some of the varieties that have short stems between each pair of nodes. Used for Atragenes and New Zealand Clematis

Two node cuttings [Fig 1d], used for hollow stemmed Clematis, such as rehderiana, ranunculoidese and heracleifolia.


Hardwood, always taken as two node cuttings, taken in the late Autumn [Fig. 2. This method can be effective on species such as, Montana, Alpina, Machropetala, Koreana and Heracleifolia. Place cuttings in sand or well drained soil in a cold frame located in a shaded position. Cuttings taken in autumn should have rooted by the late spring or early summer. Giving bottom heat to C. fruticosa hardwood cuttings is also effective.

Layering (usually carried out in-situ with the clematis planted in the ground), As new growth develops in early spring, two or three of the new shoots should be trained as near as possible to horizontal, so that in late spring to early summer these stems can be buried about an inch below soil level at a node. Rooting may be encouraged by scraping the stem for 20mm on either side of the node which is to be buried. The node can be pegged down with wire, but I prefer to use a house brick or a stone block of similar size, as this helps keep the stem moist. Rooting is likely to take place by the Autumn or in the following Spring, when the rooted layer can be dug up and separated from the parent plant. Cut off the layer one node below the rooted area and leave two nodes on the stem from where growth will appear. Pot the layers into suitable sized pots and grow them on in a sheltered position (cold greenhouse or a cold frame) until large enough to be planted out.

Air Layering, For stems that cannot easily be bent down to ground level or where the parent plant is grown in a pot I have successfully air layered stems, into a mix of moss and compost, either in pots split to fit round the stem or by wrapping polythene or cling film around the compost at the stem, damaged by scraping away the surface layer. Hormone rooting medium may be used on the damaged stem to encourage rooting. When roots are seen, either protruding from the base of the pot, or under the polythene film, the layer may be separated from the parent plant and potted on as for layering.

Root division. Some clematis produce runners, which can be separated from the


parent plant, with a section of root and stem with a pair of nodes or some top growth, which can be potted on to produce additional plants. There are a number of plants which have this habit, some that I have successfully divided to produce a few extra plants are; heracleifolia, cirhossa Balearica, the viorna section, integreifolia, ladakhiana, marmoraria, marata and some of the New Zealand hybrids, such as Little Runner.

Root Bud Divisions. (Fig. 4) I have had some success in producing root bud divisions of those clematis in the viorna group which will not propagate by conventional means, such as texensis. This will only produce about two or three plants from a root per season. In late winter examine the junction between root and stem for the presence of any developing growth in the form of developing buds, when these are present, turn out the plant from its pot and wash off the compost from the roots. Inspect the area around the buds to assess the best way of cutting the crown so that these buds can be separated by division of the stem with a some roots intact. In some cases this may involve splitting the stem or stems in two in order to get potentially two plants from one stem. A sharp knife is required for this process, but I do not us the same knife as use for taking cuttings, instead a fine pointed scalpel blade seems to work well. Any cut surfaces should be treated with a dusting of sulphur and each individual plantlet should be potted up individually into the appropriate sized pot, into your normal potting mixture, but with 20% silver sand added. I also dress the top 20 mm of the compost surface with a 1 to 1 mixture of Cocoa shells and medium composted bark. This should help prevent lichen or moss growth and keep the area between the root and the bud reasonably open and relatively dry. It is advisable to add a fungicide to the first watering, but watering should be kept to a minimum until growth starts to appear.

10) Suitable material for cuttings. Cut off and throw away the tip and the first two nodes of new fast growing stems. Cut off this material to about six nodes down from this, being suitable cutting material. This material should be converted into cuttings immediately, wherever possible. Otherwise material should be placed in a plastic bag with a piece of dampened tissue wrapped around the base of the stem. The material being kept in a cool dark place until this can be converted to cuttings.

11) Timing. Cuttings are generally taken in spring, when most of the new fresh growth is available. High Summer and Winter are not generally good times to take cuttings, but Autumn is a good time to take cuttings of New Zealand Clematis, as there is generally more suitable growth available at this time. For the amateur it is worthwhile trying to take cuttings when the material is available, for example I have sometimes acquired a somewhat rare plant in autumn which has suitable growth for taking cuttings, on occasions the parent plant has not survived the winter, but the cuttings have been grown on and subsequently planted out into a suitable position.

12) Grafting. Grafting was used extensively for the commercial production of Clematis plants, this method is only used in a few nurseries now, it does have the advantage that plants can be produced more quickly for sale, but greater skill is required in producing successful grafts.


I have tried grafting onto seed grown main root stems of C.vitalba but with no success. I have subsequently tried some of the easier cuttings onto the thick single root

stems of a large flowered hybrid with some success [Fig. 3]. I will be trying the same technique with some of the impossible viornas this year, using some of the thicker rooted varieties in this group. I place my grafted plants in the misting unit until root and top growth are taking place, subsequently moving them to the potting bench in the greenhouse until they can be potted on into firstly 90 mm pots, then into 1litre and on to 3 litre pots before they can be planted out. Note subsequently grafting onto vitalba root has been successful.

13) Micro propagation. This process is being used for commercial production of mainly the large flowered hybrids. It is possible that some of the more difficult, to impossible, Clematis could be produced in this way, but doubts about the commercial aspects of producing species Clematis for which there is generally little demand.


Best bwishes

Roy Nunn

Posted By: digger
Date Posted: 22 Feb 2008 at 2:56pm
Wow what a fantastic response, I really appreciate the time you guys are spending to teach me the "ropes". I had not even considered the depth of pots or trays that need bottom heat and yet it now seems fairly obvious that a tall deep pot will not obtain the bottom heat efficiently. I hope you don't mind that I have printed this reply of yours so that i can read it several times. I will not use it for anything other than me reading it and I will not pass it on to any other party/person. Thank you so much for taking the time to write regards digger

Posted By: Ron.G.Carlile
Date Posted: 23 Feb 2008 at 6:00pm
Hi Digger
I do not think there is any need not to circulate the information Roy has sent you I can imagine half  the readers of this site will have down loaded the information by now, which is very informative . The one thing I have noticed from ny screen it looks as thou Roy has the same trouble as I do in down loading Photo's , I still have not got the nack . There use to be a tree at the top
but it may be in a anothere place .
Best wishes and great success with your greenhouse


Posted By: digger
Date Posted: 23 Feb 2008 at 6:51pm
Hi Ron, I have used a photo site called photobucket to download pictures on another sitemaybe it will work here?. I thought I would mention that I had printed the article just in case, I think legally the author of the work has something called "intellectual property rights" and if these are breached the chap who has downloaded it can be in deep trouble. However I am sure that you are right loads of people will have printed/downloaded info from here. I have yet to order the greenhouse I am going for the biggest one I can afford once ordered it is delivered within seven days. I am eager to get the clematis house up and running.

Posted By: richardh
Date Posted: 24 Feb 2008 at 7:21pm
Most important,Digger,is to coat the outside of the greenhouse every Spring with Coolglass as the heat can be quite intense under glass in Summer. Most of this usually wears off by the end of the year and allows more light in to the greenhouse in winter.
Also far better to leave doors and vents open as much as possible to allow plenty of air movement. This helps to keep mildew at bay.
Better also to keep all plants on the wet side instead of allowing them to dry out which tends to encourage red spider mite.

Posted By: digger
Date Posted: 24 Feb 2008 at 7:55pm
Thanks Richard, i am getting some very good information from here I really appreciate it.

Posted By: digger
Date Posted: 05 Mar 2008 at 8:51pm
Hi everyone, just a few lines to keep up to speed, the greenhouse has been ordered and should be here soon, it is roughly 8x10ft ish, clear polycarb sides and twinwall poly roof.
I will get the ground levelled up tomorrow, and order in some flags from the local builder merchants. I can't wait to get going.

Print Page | Close Window

Bulletin Board Software by Web Wiz Forums® version 9.06 -
Copyright ©2001-2007 Web Wiz -