Posted: 26/08/2012 at 19:02
Give them a good drink and a tonic of liquid tomato food or seaweed now so their roots get plumped up and healthy as these are the plants' engines. Keep them watered and fed till late September when you can plant them out in the garden.
Make sure you dig a good deep hole, twice or three times as deep and wide a syou think they need. Return the soil after improving it with well rotted manure, good garden compost or bought soil conditioner and some bonemeal worked into the soil. Make sur ethe roots of the clematis are thoroughly wtared before transferring them from their pots to the ground and make sure they're buried at least 6" deeper than they were in their pots as this helps encourage new shoots. Water them in well but don't prune at this stage.
Ville de Lyon should be pruned back to about 9 to 12" high every spring in March. It will then produce new stems which flower in mid summer.The President is a bit trickier as it's a group 2 which generallly means it flowers on old wood between May and June. You then dead head, prune back any unwanted growth and feed it and it produces a second flush of flowers at the end of the summer. However it can be treated as a group 3 and pruned in spring like the Ville de Lyon. I would recommend this for next spring and then you can choose in subsequent springs when it's recovered and established itself.
Either way, feed both generously every March with clematis food plus a handful of pelleted chicken manure or blood fish and bone. Scatter organic slug pellets at the same time as slugs love new clematis growth. Keep them fed regularly till late June and make sure they don't dry out in droughts.