How to grow clematis

Clematis Florida Sieboldiana (Image: Archant)

Clematis are so popular that you may think that there is nothing left to say about them. I disagree for I think it important to warn prospective clematis owners of one or two salient points for their cultivation. They prefer to have their heads in the sun, or partial sun and their feet in the shade as they like a cool root-run. As most clematis are likely to be planted at the base of a wall of fence, probably facing somewhere between south-east and north-west, keeping their roots cool has to be a contrivance on the gardener's part.

This is partly achievable by deep planting. Take out a hole deep enough to allow an extra 15 cms of soil above the crown of the plant. Not only will this help to keep the roots cool, it can sometimes be a saviour if the dreaded, fungal disease, (Phoma Clematidina) or clematis wilt strikes. When this occurs, one or more shoots wilts suddenly. These should be removed at ground level and burnt, the parts of the plant below ground level are often unaffected and can rejuvenate either later in the season or even the following year.

Placing a paving stone over their roots is another ruse, for the soil beneath will stay cool but, my favourite method is to use a 10cms mulch of gravel for this breathes and remains reliably cool and moist thanks to condensation and being permeable, it is easier to irrigate. Always incorporate some organic matter when planting, I love well-rotted, farmyard manure but failing that pelleted chicken manure or PlantGrow are equally good. Replace the soil that you have enriched with the above and irrigate administering 10 litres of water, no need to firm the soil. Finally, top-dress with Blood, Fish and Bone meal or a slow release fertilizer and a 10cms mulch of gravel. You can now rest assured that you have done your best but watch out for marauding molluscs!

East Ruston Old Vicarage opens for the season on Saturday, March 2 on Wednesdays to Sundays, and Bank Holiday Mondays, 12–5.30pm.