Gardening Notes

HEAD Gardener’s NOTES

Andy Eddy, Head Gardener at Osterley Park & House, writes

“Over my whole gardening career I have been asked many thousands of questions but the one that pops up most regularly is how do I prune my wisteria? At Osterley we have a marvellous specimen on the south side of the mansion which is 138 feet long and gives us a spectacular show every spring with the typical mauve flowering racemes and of course a magnet for bees! It does however need regular pruning. Wisterias put on a lot of long, whippy shoots every year which need to be pruned back to keep them under control. So as to be able to complete this satisfactorily it is advisable to do it twice a year – once in late summer and again in winter when the plant is dormant. In the summer cut back to four or five buds – it doesn’t have to be too precise as the final prune in winter is far easier with bare branches and no leaves in the way. The final prune can take place anytime when the plant has no leaves and you should cut back to two buds as this will promote flowering ‘spurs’ – i.e. buds that produce flowers. Of course if you have a newly planted wisteria you will need to train and tie in many of these whippy, new shoots to make the framework for your eventual display. There is a wonderful white flowering variety that can also be grown and this makes for a stunning alternative to the usually grown type. One other thing that is worth mentioning is that you should always plant a wisteria that has been ‘grafted’ – this can easily be seen by the large bulge on the stem a couple of inches above the level of compost in the pot when first buying, this will ensure that you get a true specimen that will flower in its earliest years and with those lovely, long flowers that we all desire.”