Tips for pruning your Cornish garden in March
Late spring, traditionally Lent, is the time to get your garden pruned and into shape for the summer ahead. But where to start? Duchy of Cornwall Nursery's Head Gardener, Becky Martin, gives her top tips.
Hydrangea pruning has to be one of the most satisfying jobs in the garden. It’s easy, there are no prickles, no ladders, and the shrubs look smart and tidy instantly.
Work out what kind of hydrangea you have
They divide into three different groups!
The first group is Hydrangea macrophylla, the common hydrangea (the “ordinary” one) with either mophead or lacecap flowers, and Hydrangea serrata. [Like the blue Hydrangea Zorro below left]
These hydrangeas flower on old wood, that is stems that grew the previous year, or years.
- Identify and remove any dead, diseased or damaged wood.
- Reduce remaining stems by about 30cms, cutting above a pair of fat buds. These buds will develop into flowers in the coming season.
- On mature hydrangeas it is a good idea to remove some of the oldest stems to make room for new growth. Cut them off right at the bottom.
Those of you who are familiar with Trebah will know there are two acres of hydrangeas in the valley. The late Mrs Hibbert who lived there for many years pruned these herself in Lent. It took her all of 40 days and she described it as her Lenten penance.
The second group of hydrangeas include Hydrangea arborescens (such as Annabelle) [the delicate white one, above right] and Hydrangea paniculata (such as Limelight). These flower on wood that grows in the current year. They are pruned by cutting the whole plant back to the lowest pair of healthy buds. This will mean removing all the stems almost to ground level and creating a short stubby framework. This can be done in early spring before growth commences. If the plant is not pruned, or is not cut all the way back, there will be more blooms which will be smaller and higher up.
The third group includes Hydrangea aspera, H aspera Villosa Group, H quercifolia and H sargentiana.
These do not require regular pruning. Minimal pruning to remove dead, damaged or unruly stems can be done in spring.
Other notes on hydrangeas
Remember that hydrangeas do not have to be pruned, and nothing terrible will happen if they aren’t. It’s a way of controlling the way the plant flowers and getting the best performance to fit in with our gardening standards.
Old, neglected hydrangeas can become very tall and untidy, but all is not lost; cutting the whole plant right down to the base and starting again is the best option, though you will get no flowers in the coming year. It is good practice to apply some general purpose fertiliser as you prune. We use a handful of chicken manure pellets for each bush.
Clematis pruning is something that often worries people, maybe because the plant label refers to a pruning Group, or Code, and this creates uncertainty. It is, however, quite logical and straightforward. Group 1 are the first to flower, early in the year. Group 2 are next to flower in the summer, and Group 3 are the last to flower later in the summer.
Head over to Becky’s post on the Duchy website if you want help identifying which clematis you have! (or wait til June and it flowers, then take a pic and head to the nursery for their assistance).
Group 1 clematis flower on stems which have grown the previous year. They do not need regular pruning, but wayward stems can be removed as the flowers go over. C montana [below] is very vigorous and sometimes gets too big for its space, in which case it can be cut hard back, even to ground level, just after flowering, but this should not be done on a regular basis.
Group 2 clematis start to flower in late spring or early summer, and have a long season, especially if well fed and cared for. The flowers come from growth made the previous year, so they are pruned in late winter or early spring (February is ideal but March will do!) by cutting back the old growth to above a pair of strong buds.
Group 3 clematis are the later flowering varieties and all flower on growth made in the current year, so need to be cut hard back in the spring to a healthy bud at about knee height. It is tempting to leave all the higher growth which may already be showing signs of healthy new growth, but if left unpruned all the flowering will be way up on the plant, out of sight.
Finally, it is a good idea to feed your clematis at the same time as pruning. A high potassium fertiliser (such as rose or tomato food) applied around the base of the plant will assist flowering.