I love propagating plants. Actually that’s something of an understatement – at this time of year it’s more of an obsession. The garden and nursery are heaving with potential cuttings material and the seed harvest is taking off in earnest. I hardly know where to start. So I’ll start at the plant nearest the back door, Clematis wilsonii. It’s easy when you know how. Here’s the quick version if you just want the basics:

Choose a healthy length of stem, this year’s growth, preferably without flower buds.

Note which way is up – the two little buds in the leaf joint are always ‘up’. (Click on the picture for a better close up)


Starting from the bottom of your length of stem, cut as follows for each cutting. I like to use a slim pair of deadheading snips – easier than a knife.
– 2″ below the leaf joint
– just above the leaf joint, taking care not to damage the two buds
– snip off one leaf completely
– snip the middle leaflet off the remaining leaf.

and your cuttings should now look like these.

Mix up a very open compost – mine is peat free multipurpose with the bark bits left in, a bit of grit sand for grittiness and a good proportion of vermiculite. I like to set them out across the pot, thus avoiding the tricky problem of leaves hanging too much over the edge of the pot. Push the stems all the way in until the leaf joint is sitting on the compost surface.

Put somewhere warm (bottom heat is good), in the light but out of direct sunlight, keep moist and wait 6-8 weeks.

So that’s a basic ‘how to’. And in case you were wondering…

Is early June the ideal time to take clematis cuttings?
Yes-ish. The plants are putting on good extension growth so there is plenty of material available. But they are quite slow to root and it can be tricky to get newly rooted clematis cuttings through the winter. So about now is the latest I would take them.

Does it matter which plants you take the cuttings from?
Possibly yes. Shoots from young plants seem to root better than the same-looking shoots from old plants. The biological age of the plant can affect rooting ability.

Shouldn’t you make the bottom cut through a node for best rooting?
Yes, in an ideal world because cambial cells are clustered at the nodes. But with clematis and other climbers the cuttings would be unfeasibly long, as you must cut above a node to get growth shoots. There are enough cambial cells in the stem for internodal cuttings to take.

Why do you snip off all of one leaf and part of the other one?
Since I have cut off the cutting’s roots it can’t support much leaf area. I therefore reduce the leaf surface area by 2/3 making as few tiny snips as possible, causing as little damage as possible to the remaining leaves. The reason for leaving any leaf on at all is so that the plant can still photosynthesise.

Why don’t you put the cuttings around the edge of the pot?
There is only any point putting cuttings around the edge of unglazed clay pots as they are air porous. Roots need oxygen to respire and grow. The edge of a plastic pot is not a great place for a root to grow – less oxygen and prone to great heat changes

Do you use rooting hormone powder?
I do when I’ve got it to hand, for clematis. But it’s important not to over-use it as too much can inhibit rooting. Just touch the cut end onto a small amount and flick to remove surplus. On balance, it’s probably best to use it for clematis.

I’ve read that commercial growers root them in pure perlite – why don’t you?
Mainly because I don’t like the stuff – it behaves weirdly, floats and won’t stay still. It also dries out in no time. Probably fine if you have a full time job propagating clems and are onto them all day, but I’m busy. I need a compost that will stay reasonably moist for at least half a day at a time, if not longer.

Where exactly should I put them now?
Ideally, the cuttings should be somewhere warm (20-25C), not subject to a draught or too much temperature fluctuation. The air around them should be consistently humid to reduce stress on the rootless cuttings. It should be light, but shaded from direct sunlight. Warmth from below will speed up rooting. I put mine in a large home built propagator. The floor is a sand bed with a soil heating cable going through it and a sheet of weed control fabric on top.

Any notes on aftercare?
Don’t reach for the watering can if the top of the compost looks a bit dry. Check the pot weight and if it seems heavy, mist the cutting instead. The root area doesn’t want to be soggy and wet.

It is important to keep the humidity high around the leaf area. The cutting cannot pull up moisture to cool itself and keep the leaf turgid. High humidity reduces the stress on the leaf.

Resist the temptation to tip the cuttings out and check for at least six weeks. It will probably be about 8 weeks before they’re ready to pot on. If they aren’t ready by mid-September leave them until March. Really. They are more likely to survive.

June 13, 2011