Pruning Heracleifolias and Winter Flowering Clems.
Now is the time to give your Heracleifolia clematis their hard prune. The Heracleifolia Group are those clematis which are considered as herbaceous sub-shrubs, they are clump-forming and have strong woody stems, in fact they are most unlike what we traditionally think of as clematis.
Image of Cassandra.
In the previous blog ‘Clematis Pruning’ I suggested that you semi-prune these, just enough to remove about half last year’s growth to tidy them up a little. I always prefer to prune this group of clematis in two stages because I have found that the Heracleifolias will tolerate a late frost better if you have left some old wood on them. The dead leaf also makes a good cover over the crown of the plant through the winter, protecting the plant from getting to wet at the base of the stems.
So about early April is a good time to give these their final prune for this spring and all you need to do is prune off the old stems just above the highest new shoots and remove any dead leaves that might still be lingering around the clump, as this will help to deter slugs and snails from setting up home there.
Image of Heracleifolia Before.
Image of Heracleifolia after.
Now give them a good single handful of bonemeal and work it into the soil around the base of the plant, then add slow release fertiliser and water it in if there is no rain forecast for a few days. There is nothing more to do now except wait for their lovely display of flowers in late summer. These are such an easy, worthwhile group of clematis to grow - they will cheer up any border of the garden and, especially as several of them are fragrant!
Over the next few weeks, is a good time to reduce some unwanted growth from any of your winter flowering clematis, namely the evergreen Cirrhosa Group (balearica, ‘Freckles’, ‘Jingle Bells’, ‘Wisley Cream’ etc.), napaulensis and ‘Winter Beauty’. Their pruning, if it is needed, can be carried out any time after they have finished flowering, indeed, the same will soon apply to the Armandii Group, ‘Apple Blossom’ and ‘Snowdrift’ etc. They will now be at, or coming to their peak of flowering, so their pruning should be delayed a few weeks until all the flowers have finished.
Basically, with any of these evergreen clematis, they do not have to be pruned, but only when the gardener feels it is necessary, for instance, if the plant has more than filled its allotted space in the garden. Really, the most that is normally required is to prune off any excess growth to keep it within bounds, nothing more than a good ‘hair-cut’!
You will then find that in a few weeks the plant will make some fresh growth that can be trained in, where you want it to go; maybe to fill in any gaps in the old stems and generally to make the clematis look better.
If, for any reason you need to cut down into the very old woody stems, most of these evergreens will cope with this quite well, apart from the Armandii Group which can take exception to very severe pruning and refuse to reshoot. So be careful with these, my suggestion is to cut no lower down the stem than where there are leaves. Cutting above leaves should encourage the clematis to reshoot, but perhaps the safest is to avoid having to severely prune the Armandiis. Therefore, if growing space is somewhat limited, it would be better for the plant to be cut a little back each year, which should hopefully avoid the need for more drastic measures in the future.
Late April or early May is the time to start liquid feeding container grown clematis – Tomato feed is excellent. Once a fortnight should be enough to encourage a really dazzling display of flowers.
Look out for new stems that are waving around in the air. They grow so fast at this time of year, and they can be broken off in a strong wind, so make sure to train them in or tie them to their support carefully with split rings.
Image of Armandii Apple Blossom.