I.Cl.S. - Collecting and Growing Clematis Seeds


It is the right time of year in the Northern Hemisphere to be collecting Clematis Seeds and we have had a number of queries recently. Many of you are keen to have a go at growing your own so we hope that this page will help.


Identifying Viable Seeds

Clematis seed head

Any seed you collect needs to be 'viable', that is it has the potential to germinate. Generally viable seed will be visible in the seedhead, this is particularly true of species. If you can't see any seeds, however small, then probably none have set and so there is nothing to germinate.

With some varieties you'll find only a few of the seeds in the seedhead are viable and so you'll only be able to see a few seeds. But for all varieties, wait until the seeds go brown before you collect them as this is the most common indication they've ripened and dried and can be safely stored.

It is easy to identify seeds in large flowered hybrids as they have large 'heads'. Hybrid seed probably won't grow true to form, often producing a plant which is reluctant to flower at all. However this is how many new clematis are produced, though breeders go to great lengths to make sure they know exactly the parentage of all of their seedlings.

The picture above shows Clematis heracleifolia with some seeds that have 'set' and others that have not. Remember if you are collecting seeds, the I.Cl.S. Seed Exchange would love to receive some, please see below for details.

Fiona Woolfenden, Great Britain.

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Germinating Clematis from Seeds

Clematis seeds may take up to three years to germinate, but you should get some germination in about six months to a year. Collect ripe seed in the fall and plant in sterile seed starting mix, covering seeds with a thin layer of sand. Place the container into a zip lock polyethylene bag and place it outside in a shady spot (or a refrigerator) for several months during the winter so that they go through several freeze/thaw cycles.

Then place the covered container in a warm location out of direct sunlight and wait for your first seedling. As the seeds germinate, the small plants should be pricked out of the germinating container and planted into a small pot using a sterile soiless mix. Be very careful as the root will be a single long root in the beginning. As it grows larger it will need a larger pot, fertilizer and constant moisture. When the plant has three sets of leaves, pinch out the growing tip to promote branching.

Seeds collected from hybrid clematis will usually not breed true to the parent so you might create a new and exciting cultivar that may be named after yourself or a loved one. The chances of getting a new winner are about one in 200, but acceptable smaller flowers of little commercial value will result. They make great gifts to fellow gardeners if you get too many.

Your seedling will take at least a year to offer its first bloom and another three years to become a mature plant. I usually wait until it blooms before planting it out in the garden. A greenhouse helps. It is a labor of love! Good luck!

Bill Bird, USA.

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The Society's Seed Exchange

The seed exchange is a vital part of our Society and one of the main benefits for Members who live all over the world. The seed exchange enables Members from different parts of the world (but see below for restrictions) an opportunity to obtain seed of Clematis plants which is difficult to find in their own countries.

The best seed to donate to the Seed Exchange is from species as these are most likely to germinate true to type. Seed collected in the wild, specially from expeditions, is much appreciated by other members. Varieties common in one country are often difficult to find in another.

The seeds that you donate to the Seed Exchange should be 'viable', generally the seed in the head will be visible, particularly with species. If it is not then the seed has probably not 'set' and will not germinate. On a number of varieties you find one or two seeds are viable and the rest are not. The seeds should be well ripened and dry, this usually means that the seed head will be brown.

We would appreciate if you can put the dry seeds in a paper envelope and mark the outside with the name of the Clematis hybrid or species that you picked them from. If you collected them in the wild please add the name of the place that they were collected from.

Send the seeds to:

Marita Opalka
Wagnerstr. 7
OT Schwarze Pumpe
D-03130 Spremberg
GERMANY
Tel No: Germany 03564-22181

If you believe that you will be able to donate some seed but that it is not yet ripe, please contact Marita and let her know. The seeds are collected this year and early next year the Society will send its Members a list of the seeds available. Seeds are free to Members but we ask that if you would like to donate some money towards the running of the Seed Exchange that you add a little extra to your Membership Fee.

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Seed List 2007 Additions

The following seeds have been received by the Society Seed Exchange but after the 2007 Seed List was posted to all members of this Society as part of the January 2007 Newsletter mailing. If you would like any of these seeds, please contact Marita Opalka, stating which ones (number and name). If you have already requested seed from the 2007 Seed List, please mention this so that all seeds can be packaged together. Marita will delay sending any seeds out until the end of February in case people who have already ordered wish to add to their request.

Please note, the Seed Exchange is ONLY available to members of this Society.

All the following seeds were donated by Ton Hannink, The Netherlands, for which we are very grateful. I think you will find them very interesting.
48C. alternata
49C. buchaniana
50C. connata
51C. koreana 003
51aC. koreana 004
52C. kweichowensis
53C. rehderiana
54C. ranunuloides
55C. serratifolia
56C. trichotoma
57C. urticifolia
58C. 'Floris'

The Society makes no charge for seed to its members. However if you wish to contribute to the costs of the Seed Exchange, particularly postage and packing, the Society would be grateful. Some members do this by adding a modest amount to your membership renewal payment.

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Complete Seed List - April 2007

The following is a full list of seed currently available FREE to members of this Society. Growing clematis from seed is a very satisfying way of increasing your clematis collection, and currently we have a very interesting selection of different seed available.

If you would like any of the seed listed below, please send your request, preferably by email, to Marita Opalka, stating clearly which seed you want, by number, year of list and also by name.
2007 Seed List
1C. addisonii
2C. alpina 'Blue Princess'
3C. 'Pink Flamingo'
4C. sibirica
5C. angustifolia
6C. viticella subsp. campaniflora
7C. chiisanensis
8C. 'Columella'
9C. crispa
10C. crispa, addisonii, viorna, small flowered hybrid texensis
11C. crispa 'Prince Charles'
12C. × diversifolia 'Heather Herschell'
13C. 'Fascination'
14C. fusca
15C. fusca var. ianthina
16C. 'Hendersonii'
17C. hexapetala
18C. hirsutissima
19C. integrifolia
20C. 'Alionushka'
21C. integrifolia Mix
22C. 'Rosea' (integrifolia group)
23C. intricata 'Harry Smith'
24C. ianthina var. kuripoensis
25C. 'Jackmanii'
26C. 'Jackmanii' 'Perle d'Azur'
27C. japonica
28C. koreana
29C. koreana var. lutea
30C. ladakhiana
31C. macropetala "weiß"
32C. montana
33C. napaulensis
34C. patens
35C. pitcheri
36C. 'Propertius'
37C. recta
38C. recta 'Rubra'
39C. repens
40C. versicolor
41C. viorna
42C. viticella
43C. viticella (dark purple)
44C. 'Étoile Violette'
45C. 'Little Nell'
46C. 'Minuet'
47C. "no name"
48C. alternata
49C. buchaniana
50C. connata
51C. koreana 003
51aC. koreana 004
52C. kweichowensis
53C. rehderiana
54C. ranunuloides
55C. serratifolia
56C. trichotoma
57C. urticifolia
58C. 'Floris'
2006 Seed List
3C. campaniflora
4C. chiisanensis 'Lemon Bells'
7C. mandschurica
10C. 'Heizawa'
11C. heracleifolia
18C. montana var. rubens 'Odorata'
20C. montana var. rubens 'Vera'
22C. napaulensis
25C. recta 'Purpurea'
26C. repens
28C. vine ('Henryi')
29C. viorna
30C. viticella
31C. viticella (dark purple)
32C. viticella ('Minuet')
33C. stans (3 types)

The Society makes no charge for seed to its members. However if you wish to contribute to the costs of the Seed Exchange, particularly postage and packing, the Society would be grateful. Some members do this by adding a modest amount to your membership renewal payment.

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USA Restrictions

The US Federal Government had introduced legislation that prohibits the sending of seed to the USA unless it is accompanied by a phytosanitary certificate from the country of origin which for small Societies such as ours would be too expensive.

This restriction has now been lifted for small quantities of seeds. The Society has completed a test sending successfully and so we are now able to resume sending seeds to our US members.

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@ K.Woolfenden

All information contained at this site is personal to Ken Woolfenden and
does not represent the official view of the International Clematis Society.
@K.L.Woolfenden